Tips, tricks & tinkering

Contents:
Contents:

Preventing problems - taking care of your Brompton


Riding issues
Folding and unfolding issues
Carrying or rolling issues
Taking a Brompton aboard motorised transport
Regional information concerning folder transport
When and how to leave your Brompton unattended
Transporting (more) luggage with a Brompton
Trailers
Bicycle computers, mirrors...
Quick repairs on the roadside
Beautifying a Brompton
Warning! There's no way back after this!
Maintenance at home
Spotlight on tyres
Spotlight on wheels (rims, spokes and hubs)
Spotlight on brakes
Spotlight on lights
Spotlight on the seatpost and saddle
Spotlight on handlebars
Spotlight on the (hub) gears
Spotlight on the rear sprocket
Spotlight on the chain
Spotlight on the front chainring
Spotlight on the bottom bracket
Spotlight on pedals
Genetically Modified Bromptons

Preventing problems - taking care of your Brompton

When you just purchased a (used) Brompton

Tips, tricks & tinkering - A little modification I made to keep water out of the brake cables

Retension spokes

if you are not a lightweight person, to prevent Tips, tricks & tinkering - Broken spokes

Toss out abbrasive brake blocks

Unless you're planning to regularly perform Tips, tricks & tinkering - Basic brake care, read about Tips, tricks & tinkering - Alternative brake blocks.

Grease

Regular checks

Tips, tricks & tinkering - Adjusting Sturmey Archer hub gears

Basic brake care

Larry Chinn - The Freewheel, Sep 1999:
If you look at your rims, you will see bits of aluminum looking like tiny bits of glass impeded in the pad. File them down until they look clean. Sandpaper your rims similarly removing all remnants of dirt and rubber.
You need be much more vigilant about clean rims and pads on a bike with fenders
Also quality of the pad and rim make a big difference much like tires and anything else on a bike. Despite the fact I have Shimano XTR V-brakes and Mavic MA-2 rims on my 700 cm hybrid, I sandpaper the rims and file the pads to prevent squealing and improve braking, especially in the rain.

Infrequent inspections (but do it sometimes!)

Replace the brake cables

The pre-March 2000 brakes with pear shaped cable ends break easily (Tips, tricks & tinkering - Brake cables) Don't risk it!

Check the handlebars

Before they break (Tips, tricks & tinkering - Broken handlebars)

Check the frame clamps

Check for frame cracks

Check for loose pivot bolts

They are threadlocked, but can work loose under heavy use. If they are, hurry to the dealer or carefully do the reverse of Tips, tricks & tinkering - Removing the rear triangle.

Check the front carrier block

Tips, tricks & tinkering - Front bag jumping off: front carrier block maintenance

Check suspenion block pretension

Tips, tricks & tinkering - Creaking

Check rim thickness

before you suffer from Tips, tricks & tinkering - Rims worn out

Check for handlebar cracks

before you suffer from Tips, tricks & tinkering - Broken handlebars

Grease the front hub and tighten its cones

Tips, tricks & tinkering - Loose/worn front hub


Riding issues

Problems covered elsewhere:

How can I go faster?

To improve transmission efficiency, from muscle to movement:

Rolling resistance tests

Stein Somers, May 1998:
With a fresh pair of primo's (mail-ordered from and then taken back to England...) I cycled around until I found paradise: a low traffic, wind shielded stretch of smooth tarmac descending steeply and then rising gently, with well spaced road markings starting at the perfect place. One problem was I didn't have a pressure gauge... Anyway I let myself roll down and up again without peddling and counted the road markings, for different bike configurations. The results are in the table below the load of text I will now produce.
While establishing the accuracy of the test, as well as a measure for the 90psi still left in my rear Raleigh Record, a puncture crossed my way... down to the 70psi my compact pump can deliver, at least given enough human power.
First test: the best coasting gear of my five speed. Corresponding to the sound (and feel, I used to wonder?), I found 2nd gear is best, 4th worst and the others lie somewhere in between. Sometimes 3th gear is as silent and as smooth as 2nd, sometimes it seems something inside sticks and 3rd makes more noise and the bike doesn't roll as far. All the same, I conclude that the circle around the 2 on the five speed gear controller means not only "adjust the rod in this gear" but also "0th gear" for peddleless cruising.
Second test: I exchanged the rear Raleigh for a Primo, and... my goodness, it clearly slowed me down! In retrospect the difference wasn't that great and I'm sure my arms didn't quite push up the psi in the Primo as they did in the punctured Raleigh.
I then set my hopes on the front tyre. This was still a Raleigh set a low pressure because lately I had been riding through the cobblestone infested centre of Ghent. What a relief when this proved to be the place where a Primo scored! Particularly if you inflate them at a moderate pressure.
Just in time the idea occurred to relate these results to other topics of riding efficiency. Here we go. The Gain/Loss numbers reflect the extra distance I could roll compared to the reference. This is definitely not a linear measure!
Reference = Standard T5 = Raleigh Records at (very roughly!) 60psi, coasting in 2nd gear, upright riding on the standard best folding handlebar position, pannier clipped in the front luggage block, 95kg total load, tall 1m96 rider. Anything else? I carried the same amount and shape of load on all tests and repeated every roll several times (I even postponed organic waist dumping for the sake of science! I did sweat under the midday sun though...).
Change Gain/Loss (accuracy: +/- 0.5)
Rear 40psi Primo -1
Rear 60psi Primo 0
Deflate front Raleigh to 40psi -2
Front 40psi Primo +1
Front 60psi Primo +2
Handlebars raised 15cm via curved bar ends (very upright and comfy) -1
Lie down on handlebars (very aero and uncomfy) +5
Lift legs and align on main tube (scooter like, still comfy) +1
Tie pannier to rack +1
Coast in 4th gear instead of 2nd -1
Engage Nordlight dynamo -1

Suspension versus efficieny (biopacing?)

How can I improve comfort?

Discussed elsewhere:

Changing the Brompton's gearing set-up

Three things you might desire: For opinions on what is a suitable range, see The first steps to folding wisdom - Reduced gearing.

What are gear inches?

Peter Amey, Jul 1998:
Gear inches are the diameter in inches of wheel that would roll as far in one revolution as the bike would travel for one turn of the pedals in a gear of the same number of inches. Imagine an "ordinary" (or penny-farthing) bike; a 90" gear is the same as riding one with a 90" front wheel.
Metric gears are usually in terms of the actual distance travelled for one turn of the pedals. i.e.
pi * GearInInches * ConversionFromInchesToMeters
Ruud van Tol, Jul 1998:
In other words: it's the (imaginary) size of the wheel when there wouldn't be any gear.

Is it normal for the hub gears to go "tick-tick-tick" when you pedal forward?

My heels hit those darn castors!

Custfold:
[The rear castors, at the front of the rear rack, are] odd shaped rollers that used to catch my heels (usually its women who have the problem as they cycle with feet closer in). You can experience the same problem with luggage: Tips, tricks & tinkering - Heal hindrance.

Waggly rear ends

Roland Elsenberg, Aug 1998:
[...] I found it less precise in steering. This is probably due to a worn hinge between the main frame and the rear triangle.

Adjusting suspension

If the suspension is too weak for your weight...

Rear mudguard too short (the mud striped back syndrom)

Loose frame clamp

Custfold, May 1998:
I've been experiencing a loose main frame clamp with annoying regularity lately. This ocures even when I'm positive that it was fully tight at the start of my ride.
It may be that the clamp plate has stretched - I'm checking with Brompton for a service gauge measurement to determine when a plate should be changed (e.g. the gap between clamp seat and frame plates). It may be movement in the frame fretting at the joint.
The indicator when riding is the distinctly unnerving floppiness in front end response when braking hard.

Loose chainguard

Undesirable sounds

This is not the most common complaint, but a frustrating one. It seems all sounds can be supressed, except those coming for the hub's internal gears. Some report they rattle, some hear no more then the normal ticking in high gears.

Localising the nosiy culprit

Clanking

Nico van Beek, Aug 2000:
I bought, some one and a half year ago a T3. Great fun. Everybody wanted folding demo's. However, after some time a vague clanking started in the neighbourhood of the back-wheel. Couldn't find exactly where. I performed greasing and tightening of screws and nuts. Didn't solve the problem. So: back to the dealer, who checked the bike. "Did you solve my problem"? No, that appeared to be not really possible. Had to do with something within the nave of the back-wheel. A common Brompton problem. Dismantling the nave would not give any solution. Not very satisfactory! The rattling became worse (and in Holland we do not have tarmac everywhere as in California). So I wrote to the factory. Answer came from the main distributor in Holland by telephone. A nice chat about grease, oil, tirepressure etc. However it may be: a well known problem! Had to do with the general construction: only one hinge between back and front parts and therefor no possibility to spread the rumour over the total frame. Again, not satisfactory. I'm now in the stage to advise others not to buy Brompton, unless they can cope with a lot of, now very noisy rattling. I took the nave completely apart, greased, oiled, well did everything, but the problem still exists.
Freewheeling on, let's say, rough surfaces, is the main problem. Has nothing to do with little wheels but with the inside of the SA nave.

Squeaking

Stein Somers:
My new T5's has been taken over by a mouse. It hides inside the suspension block and produces noises that make the Brompton sound like a rusty old bike.

Creaking

Cracking

Custfold:
The other day I noted that the paint at the n/s (left) joint between the chainstay and pivot hinge plate had lifted. My concern was justified, when the 'crack' noises which had been up to then untraceable revealed their source when the chainstay split neatly around the circumference at the high stress point where the thin walled tube is brazed to the thicker pivot plate - modern Bromptons do try to spread this load by having a slightly different design to the first machines produced, which had the benefit and weight of the substantial integrated carrier and reaer frame. With the tie between the rear triangle and the main frame, the bike remained rideable with care to limp back to base, albeit with the key clue to any incident like this, the unnerving crab wise travel of the main frame when compared to the road, as one looks down - fi your bike starts doing this look carefully at the frame for any damage..
Note that with the rear frame securely lashed to the main frame seat tube, I have 'ridden' a bike with both chain stays fractured after a particularly severe bout of damage. The n/s stay rarely goes in normal use, as the o/s is the one subjected to cyclic compression & tension loads, but the attachment of a trailer will obviously affect this - especially if the load is all going through the n/s of the triangle to the rest of the frame.

Ticking

Don't be alarmed by the normal ticking of hub gears (Tips, tricks & tinkering - Is it normal for the hub gears to go "tick-tick-tick" when you pedal forward?).

Clicking

David Goldfarb, Jun 1999:
My Brompton seems to have developed a click that occurs when pedaling with some resistance (i.e., no click when coasting, so it's not from the wheels), at a rate of one click per crank in any gear (so it's probably not the gears). Anyone else have this? The bike is pretty new (maybe 3 months, 400 mi. or so) for bearings to start wearing out.

Screaming or scraping

Richard Lighton, Jun 1999:
At the moment my problem is a scream (not a squeal or squeak, a full blooded traffic stopping scream) from the front brakes. I've cleaned the (fairly new) brake pads, adjusted them, aligned them, cursed them. They still scream, mostly in low-speed braking. The back brake with the same pads is as silent as one would expect. Any ideas anyone?

Rattles from the rear

Norman Tulloch, Nov 1997:
On road surfaces which are less than perfect (e.g. on country roads which are tarred but not exactly silky smooth), I get an annoying and persistent rattle from somewhere at the back of my Brompton T5. I cannot reproduce the problem when the bike is stationary,

I have tried tightening all the screws and so on at the rear but this has made no difference. (I have not tampered with the rear hinge screws since the Brompton owner's manual emphasises that these should be left alone.) At one time I suspected that the mudguard might be vibrating against the luggage rack. I therefore put some pieces of foam rubber between mudguard and rack but still the rattle remained. I have wondered whether the source of the problem might be the castors on the rear rack, but if I try riding with my feet on the castors on the front of the reack (don't try this at home, children), the blasted rattle is still there.

Has anyone else had a similar problem? I so, how did you cure it, or did you just hurl the bike over a cliff, driven into an irrational rage by the rattle?

Noise from the front

Willi Mindak, Jun 99:
For a couple of weeks now my T5 has developed an irritating noise that repeats itself with every turn of the front wheel. I suspected the wheel bearings or the cones, but when I examined them they looked o.k. to me. The bearings showed no wear at all (at least I could see none), and the cones had just a small, uniform line of wear were the bearings are running. This 'line of wear' is visible, but you don't feel anything when you run you finger over it. Regreasing the front hub brought no improvement, neither did turning the wheel back to front. The noise only appears when the bike is ridden. When the front wheel is spun without load all is quiet. Can the noise be caused by uneven spoke tension? Any ideas?

Silencing a whiny generator

Channell Wasson, Jan 1998:
Try this
  1. A little oil around rotor
  2. Check alignment of rotor to side wall
  3. Super glue two o rings on rotor. ( Be sure not to get "s/glue" on rotor shaft area) [or get a regular dynamo cap from any (European?) bike shop]

Why is the Brompton's steering sensitive?

Riddell, Toby, Jun 2000:
Is this anything to do with the frame geometry, in particular the trail?
I have noticed that when pushing my Brompton along, holding it just by the saddle and steering it by leaning it one way or the other, it is less responsive than other bikes, that is say the amount of turn is small for a given amount of lean. I think this reflects a shorter trail. And this in turn is reflected in the fact that it's harder to balance the bike when riding it hands free, there is less self-centering.
Does this make sense?
When researching folding bicycles I came across a report concerning a particular model of Dahon. It had a geometry which meant that there was no self-centering effect. A case came to court because someone was riding one when he looked over his shoulder and took one hand off the handlebar - because of the lack of self-centering he could not tell with one hand which way the front wheel was pointing and it turned to 90 deg. and he was deposited on the deck. So presumably this Dahon had no trail at all?

Riding on the sidewalk - is a Brompton a children's bike?

Wobbles and top speed


Folding and unfolding issues

Covered elsewhere:

Handlebars suddenly flipping open while folded

Doug Faunt:
The bike folds fully, and the clip fully engages, it just doesn't hold under any kind of stress. It's pretty loose, in the best of circumstances.

Frequent Folding fosters Frame Flange Failure?

john blackburn, Feb 1999:
How many times can you fold a Brompton? Each time the screw is tightened in the frame folding flange, the threaded hole gets a little more worn. It would be better if the wear occurred in the bolt alone; this could then be replaced as required.
As an experiment, I got a new bolt (M8 x 75mm, high-tensile steel to spec 8.8), and 2 8mm full nuts and changed the system to a captive thumb-wheel that runs along the bolt, which is screwed and locked into the threaded hole in the frame. One of the 8mm nuts is nested in the hex hole in the thumb-wheel (the existing M8 x 50 HT bolt can be eased out carefully), and the other 8mm nut is used as a lock-nut to stop the bolt rotating. The existing washers were retained and used exactly as before.
The result is a captive thumb-wheel that cannot vibrate out or be stolen, and a bolt that can be tightened as often as necessary without damage to the frame.
It doesn't look too good; maybe there is a better method of more elegant appearance. But the existing system - screwing a screw into a tapped hole in an expensive frame thousands of times and not expecting trouble - doesn't seem too good either. Nor does the idea of folding the machine dozens of times a day and leaping onto passing buses. Now if it were made of magnesium alloy with nylon wheels and weighed 3kg...

Is there a preferred gear to select before folding?

Robert Payne, Mar 1999:
I've heard many different statements about what gear to leave your bike in when folding (2, 3 and 5).
Which one is optimal?
I've been leaving the bike in 3rd when it is folded. Is folding in 5th going to save me trouble with adjustments?

Coping with passers-by: "how much does it cost?"

Peter O'Reilly, Jul 2000:
While with the Brompton, I am frequently asked the question, "How much does it cost?" It is by far the most common question asked. At first it was a bit humoring to see the incredulous expression on ones face when they find out it costs more than say a couple of hundred dollars (or any bicycle for that).
Frequency aside, I do mind it a bit when asked such by a stranger on the street. "Bike jacking" is not such an uncommon thing here in NYC. It's not the only thought that pops into my head when asked. Your opinion may differ, but asking indiscriminately such a question to me is like asking "How much money do you have in your wallet?" Yes, I am aware, for most it is out of genuine curiosity, but it seems rather crude to ask. When asked sometimes I will tell the true cost other times I will give a low ball figure.

Carrying or rolling issues

Techniques for carrying a folded Brompton

See also: Tips, tricks & tinkering - The Brompton folding pedal folding too far

Stop your rear end from sagging

When you lift an unfolded Brompton, the rear triangle hangs down. This is good when you're parking or folding the bike and you swing the triangle completely under the frame. But if you just want to carry the bike, for example up stairs, unless you're quite tall, the triangle will scrape the ground and make carrying a nuissance.

Put your bike on a diet

Carrying assistants

Tips, tricks & tinkering - Improving the castors, Tips, tricks & tinkering - Rolling on the castors, or...

Collapsable luggage racks

Straps to help you carry a Brompton

Bags to carry a Brompton

See also Tips, tricks & tinkering - Suitcases to serve and protect a Brompton

Rolling on the castors

Some folks including myself are disappointed that it is impossible to roll a folded Brompton around on its castors, and impractical to apply the official pulling method, i.e. lifting one side of the package with the handlebars.

Improving the castors

Removing the original castors - they're stuck!

Alasdair Baxter, Sep 1998:
The original front castors are fitted using Loctite or some similar compound and, try as I might, I couldn't budge the cheese-head screw with an ordinary screwdriver. Ka Lun Tam, Dec 1999:
I have my power screwdriver at maximum torque and it's just not budging. In fact, it's starting to strip the screw head so I'd better find the right solution soon or I'll have nothing for my screwdriver to connect to! Stephen Hosking, Sep 1998:
I didn't have any problem removing the old castors. [Neither did I]

Alternative castors

Using improved castors

Broken castor

Andras Toth, Jan 1998:
I would like to draw everybody's attention to the danger of jumping off your bike in a rush. A few days ago I was hurrying to catch a suburban train, so I stopped at the station the following way: at a more or less reduced speed (I was already on the sidewalk) I braked and jumped off the bike in the same moment. Result: since my weight was not keeping it down any longer, the rear wheel assembly swang around and swapped into parked position with such force that when landing a piece of one of the small plastic wheels broke off. I wonder why these small wheels are made from plastic and not rubber, in which case not only would they not break so easily but it would be also more convenient to drag the bicycle in a folded position. I wonder also why the Brompton manual does not warn the user to be careful when stopping. So when you stop, don't get off your bike until it is in a completely stationary position.

Bent rear castor wheel stays (L-model)

On all Bromptons, the front castor pair is mounted on the rear frame triangle. On T models, the rear castors are mounted on the rack. On L models, the rear castors are mounted on special stays.

Bent front castor wheel stays (T-model)

Anthony Cartmell:
The curved frame tubes on the rear frame which support the little wheels closest to the suspension rubber have got bent on my Brompton. I think it was caused by my sitting on the folded package while waiting for trains. I have managed to straighten them a little but they must still be a bit on the weak side. The result is a not-quite-so-stable parking position which can cause problems with a heavy front bag!

Taking a Brompton aboard motorised transport

Ensure your luggage is not considered a bicycle...

...because transporting a bicycle is usually more expensive than an equal amount of anonymous luggage. This is also usefull for bringing your folded bicycle into places where bicycles are banned (Tips, tricks & tinkering - Forced separation - when folders not welcome) or for insurance matters (Tips, tricks & tinkering - Legal matter - is it still a bicycle?).
The advice is to hide the folded bicycle under its cover (Tips, tricks & tinkering - Covers); if an official gets suspicous, deny it is a bicycle.

Can we sit on a folded Brompton?

Andras Toth, Mar 1998:
I have read on several occasions in this mailing list that sitting on the folded bicycle could modify the way the handlebar slips back to its place to the point of not being able to fold the bicycle correctly. What is the truth about this? Does it happen automatically, or is it exceptional? Sometimes the urge is just too great to sit down on it while waiting for the train. Also, I had to put a sign saying "DO NOT SIT ON IT" on the frame after somebody used my folded bicycle as a seat in a crowded conference room.

A Brompton in a bus

Alasdair Baxter, Nov 1998:
The last time I took my Brompton by bus, I put it in the largeish luggage/pushchair compartment at the front. However, when the bus driver braked sharply, my bike had an undignified fall to its side. I could have put it against the front wall of the compartment or facing the other way but it would still have fallen on its side in a violent manoeuvre by the bus.
It occurred to me that, if I could get a strap fitted with Velcro and some 10 to 12 inches long, I could fix the bike to the horizontal tube forming a wall of the luggage compartment and the bike would stay upright. What I have in mind is something about the size of a small dog collar but with Velcro instead of a buckle.

A Brompton in front of a bus

Dave's trailer equipped with a bike rack, holding another Brompton Custfold, Jun 1999:
I work with Sportworks on bringing their [bike carrying] racks into Europe, and have had the Brompton on racks regularly - the Moulton may fall foul if it has front rack fitted. 16" wheels do fit but MUST be put in such a position as to ensure maximum pull on spring in retaining arm - one way is to hook over the luggage block - but usually its as easy to fold the bike!
The Sportworks rack is fitted to around 20% of US urban bus fleet at last count and carries over 250,000 bikes/month on recent estimates from user feedback.

A Brompton in the trunk of a car

Legal matter - is it still a bicycle?

Don't lose your bits

The problem

The cure

Another bit not to loose

The Brompton comes with a platic cap over the left front wheel nut, protecting the frame (when folded) from the sharp edges of the front wheel nut. To prevent you from loosing it, attach it to the frame with a zip tie as demonstrated on this bike from Velodroom (who always do this).

If you have lost it or you want a second one to protect the world from the other wheel nut, try... R.Hainsworth, Aug 2002:
[...] the plastic screw top from one of those 1 liter tetrapack cartons which are used for orange juice and similar. The carton is the one with a "gabled" top, ie. /\ with a screw cap one of the "roof pitches" and the screw cap fits the B wheel nuts perfectly when properly trimmed.
A further advantage is that the top comes in a different colour according to cartons contents so an approximate match or psychadelica can be achieved for the discerning B owner.

Bromptons on commercial air flights

Testimonials

RL Bob Morgan, Oct 1997:
I'd be interested to hear from folks who travel with their Bromptons on regular old commercial air flights (we all know that it's the official bike of private pilots ...). I think Channell told me once that he has taken his as carry-on and put it into the overhead bin. This seems attractive, but I can imagine the airlines taking a dim view and grabbing it from me as I try to board the plane, throwing it into the luggage compartment and smashing it to bits. Do people really do this regularly, or do they shell out for $150 hard cases? Does the story vary by airline? Does it help if you disguise it?

In the cargo, do I need to let some of the air out of my tyres to prevent them from bursting?

Packaging a Brompton - coping with evil baggage handlers

Suitcases to serve and protect a Brompton

See also Tips, tricks & tinkering - Bags to carry a Brompton

Suitcases that turn into trailers

The traveller's dilemma

Richard Lighton, Oct 1998:
I had vaguely hoped that the hard-sided travel case that Channell Wasson sells came with a trailer conversion kit so that I could tow it if necessary, in the manner of the neat thing that Bike Friday sell.
Sadly this is not so.
So the problem is: I somehow pack my Brompton and arrive at an airport and am delivered thousands of miles away with said Brompton and luggage. Sooner or later I will want to fly back. Meanwhile, how do I move the luggage and whatever carrying case I used if my means of leaving the airport is Brompton? You may assume I travel light, and that anything I'm carrying will fit into the Brompton case (once the Brompton is removed). You may also assume I have ten miles (16km) to go before I can leave the case somewhere.
Possible solutions I see are:
  1. Bike Friday travel case (I don't think the Brompton fits)
  2. Bykaboose trailer (How small does it fold? How do I transport that?)
  3. Cardboard disposable packing case. (One came wrapped round my bike when it was delivered, but what do I do on the way back?. Do airlines provide on-the spot packing? Are these really robust enough to stand up to passenger airline baggage handling with a very high probability of the bike being instantly rideable on arrival?)
  4. Some way of attaching a (now loaded with other stuff) case that held the Brompton to the Brompton.
If solution 3 is the way to go, how much time do I have to allow to sort out the hassle of getting the case, packing the bike, etc? I can reasonably assume I can pack everything else in a way that I can carry on the bike.
(Getting the bike to the departure airport is assumed not to be a problem)

Inflatable Cases?

David Dodson, Apr 1998:
How about someone making inflatable cases? To a first approximation this would be like wrapping the folded bike in an air matress. On leaving airport: let air out, roll up; At last garage before arriving at airport (or by hand pump in emergency): unroll, inflate.
Careful design could allow a neat hinged box shape with ample pneumatic padding all round. Important: several separate air compartments are needed to allow effective padding to be maintained in spite of some puncture(s). Use same puncture repair kit as for inner tubes?
A challenge for all kit makers! If you read it here first, make a Brompton pneucase first...

Floating cases

JP Desbruèhres, Oct 1998:
Flying is interesting but you are making no serious effort on your private folding plane containing your fodable bike the trailer of which can easily carry your toothbrush and the folded plane.
I am working very seriously on the foldable boat containing the folded Brompton and vice versa. The reason which started the whole process was a metaphysical question I could not answer:
"Why cross the river on the bridge ?"
If anyone has a better answer I would like to know.
If not visit the Nautiraid Website: http://www.nautiraid.com E.mail: phguyot@nautiraid.com

Regional information concerning folder transport

Aboard ground public transport

(planned for a nearby millenium: a clickable map to index this list :^)

Custfold, Sep 1998:
The Bikemap.com site run from Philly is pretty good at giving details on bikes with most forms of transport too.

Belgium

France

Germany

Netherlands

UK

Hungary

Europe

USA

Covers


When and how to leave your Brompton unattended

Take your Brompton inside or leave it outside?

Forced separation - when folders not welcome

Dave H, Jul 1998:
I would be interested to know of instances of anyone being ejected from an establishment for the crime of carrying a folded Brompton. I was recently asked to leave Washington Union station by a police officer for wheeling an unfolded Brompton and when I asked the reason I was advised that bikes looked unsightly in the attractive station! I promptly folded the machine before her eyes which she seemed to grudgingly accept. I was later ejected from a Washington museum for wheeling a folded Brompton into the entrance to make an enquiry at the reception desk!
I believe that considerate use/presence of any bicycle should be permitted in any situation where other people are not put to undue inconvenience (eg soiling carpets or danger (eg grazing shins) - including supermarkets, railway stations and public houses. I tend to assume that my machine (folded or unfolded as suitable) will be accepted and then attempt to negotiate with any official who gives me grief, if necessary asking to speak to someone senior. You can also deny your luggage is a folded bicycle: Tips, tricks & tinkering - Ensure your luggage is not considered a bicycle....

Some Bromptons are not mistaken for wheelchairs

Locks

Osbert Lancaster, Jul 1997:
I'd originally assumed I wouldn't need a lock as I could always put the Brompton inside - but I now realise I'll be going to places where this is possible. I don't want to walk around the Botanic Gardens for instance, carrying it.
Any suggestions for a suitable lock? I assume the issues will be security, weight, stowage (I wont always have the pannier with me), and of course cost.

Transporting (more) luggage with a Brompton

The Brompton rear carrier

Stowing luggage on the rear carrier

The rear carrier's bungee straps

Ann Jones, Apr 1998:
Having very recently become the proud owner of a brand new T3, I had my first excuse to take the bike out (thanks to all the lovely weather we've been having) and use the rear carrier.
I tied my stuff to the rear carrier using its own straps, and put the bungees on just as a bit extra support. What I was carrying was *not* anything sizeable by any stretch (pardon the pun) of the imagination, merely a small package. 3 miles later the bungees had stretched badly and had the elastic properties of something not very elastic. Now the damn things won't hold themselves to the carrier...
Anyone else had this problem?

Weight capacity

Heal hindrance

David, Nov 1997:
using the rear rack means you have to pedal with your heels or they can bump against what you are carrying... small irritant in an otherwise fine object...

Adding a rear carrier to an L-model

Reparing the carrier

Alternative front/rear luggage racks

Stowing luggage on the front

The Brompton front carrier block

A standard Brompton accessory to easily mount the cloth pannier or shopping bag.

The Brompton cloth front pannier

You also want the front carrier block to fix it (Tips, tricks & tinkering - The Brompton front carrier block).

Is it waterproof?

Making it waterproof

Brompton touring bag

Other panniers on a Brompton

Front bag jumping off: front carrier block maintenance

David Edge, Sep 1998:
On two occasions recently I have had the standard front bag jump off the front. In both cases the bag was fully laden to 15kg and in both cases I was traversing speed bumps in industrial premises which were a bit steep. Nonetheless, I had slowed to about 8mph, it wasn't as if I was caught unawares at high speed.

A laptop in the front bag

Saddle bags on a Brompton

Storage of emergency equipment inside the frame

Baby-seats on a Brompton

Hans Langen, Aug 97:
Is there a safe and simple way to use baby-seats for bikes on a Brompton?

Dave Holladay

Dave Holladay (<<CUSTOM=FOLDER>>)
PO Box 15174 Glasgow G4 9LW
0141 332 4733 Phone/Fax
is extraordinary enough to deserve his own section. He comments on products he developes, uses and sells:

I ride 100" fixed wheel on 27", and used to ride up to 128" including up moderate hills with a geared machine - I have sheared 4 TA cranks off at the axle socket in 15 years, and frequently fractured chainstays, seatstays - the only crank axle housing which has survived without 'belling out is the Nervex on the Scot, all others have to use cartridge bearings. [...] I broke an AW axle aged 14, and continue to bend all but the best quality solid rear axles, and break SA hollow, slotted ones. [...] My weight 95Kg - say 210lb, plus occasional 60lb pack, and up to 250lb on the trailer, and the front pannier......
My original 1989 front forks (about the only original bit on the bike) appear to have given up the ghost - I'm wary about riding it with the trailer (although the last trip -walked home with 70 sheets of hardboard (at least 150Kg)), once I get both brakes up to scratch. The problem is that the forks 'knock' from side to side, suggesting that the steerer has fractured and the steerer bolt & wedge are the only things holding the whole lot together. Not bad considering that I've seen out at least 3 sets of frame units (front/rear) and 4 or 5 rear triangles - interesting that the current rear triangles seem to be lasting with no problem, now the pivot spindle must be wearing more (going by the wear on previous exchanges).
I used to build 36 spoke 27" wheels in the 50 minute train trip between Edinburgh & Glasgow, and usually reckoned to fix a puncture in the 8 minutes between Paisley and Glasgow.
The main tube meets the rear wheel assembly (triangle), adorned with Dave's replacement suspension unit, retaining strap, and half of the skatewheel conversion kit. Also a Blackburn MP-4 pump fitted through Dave's adapter instead of the standard mini pump.
Hinge connecting the front wheel assembly (left) with the main tube (right) including Dave's clamp plate retaining kit to secure the plate and bolt (far right).
Nordlicht dynamo fitted on front fork, B&M Lumotec Plus front light, and V-brakes!
T-model rear rack with a B&M Toplight and a 4D-Lite Plus on the mudguard, and the other half of the skatewheel conversion kit (notice the alu extensions).
With Dave's custom carrier fitting to the standard Brompton luggage block, you can move a lot at once...
And since that's not enough, Dave is developing a trailer built around a waterproof box...
... or around a bike carrier. Notice the chopper handlebars on the black Brompton and a smaller custom version on the white Brompton. The black Brompton has two chainrings and a simple freewheel. The white one features an early version of the castor kit.
Shopkeeper to Dave's business partner:
"Your husband will call in?"
"Yes he's coming through on bus"
"Oh but it's heavy, he'll need a car"
"He'll decide when he arrives"
At the shop:
"Oh your wife said you'd be bringing a car"
"I don't have a car and I don't have a wife."
"How can you take the package?"
"Just put it on the carrier" and leaves the bemused shopkeeper.
One PC & 17" monitor. Note that the bike is now fully HS 33 hydraulic braked - nice daglo casting finishes. The led lumotec conversion is fitted in its wooden plate, as is a freecoaster hub (1-speed) and a SON 80 dynamo. First of 2 Secutec B&M experimentally mounted on rear rack stay. Note how using the Smartbox on rear kept heel clearance for my size 11's. Sorry about the pedals - need to get new set...

Estimated GVW based on riding over weighbridge (digital 0kg-50,000kg) at Dover Eastern Docks with a similar load is c. 200kg including 100kg of me. Very smooth ride, no major problems apart from limited handlebar swing.

A Cresswell Micro equipped with, among other stuff, a Brompton luggage block.

Trailers

De Clarke, Feb 2000:
http://www.ucolick.org/~de/AltTrans/trailers.html tells my short history with trailers so far and what features seem to me to be good/bad.

Trailer reviews

See also Tips, tricks & tinkering - Suitcases that turn into trailers

S'Cargo

Deborah Eacock, Mar 2000:
During a San Francisco folder ride a couple of years back, Len Rubin had a wonderful little trailer called an S'Cargo.

Bykaboose

Bike Hod

Folding cargo trailers

Child trailers

The trailer's tyres

David Hansen, Aug 1997:
I'm thinking of buying a Bike Hod trailer to use on a Brompton and other bikes.
Has anyone had experience of the brave new solid tyres that are fitted to new Bike Hods? I hear that they are not a good idea on cycles, does this apply to trailers as well? Would I be better off with conventional tyres?
The Bike Hod will be used on roads to transport light and heavy items.

davidh@spidacom.co.uk, Sep 1998:
[...] what would happen when I tighten up my Bike Hod fixing to the post. This deforms metal seatposts, will it shatter a carbon fibre one into a thousand expensive pieces?


Bicycle computers, mirrors...

See also:

Bicycle computers on a Brompton

Bicycle computer technology

Harris Cyclery recommends that the magnet mounted on the front wheel spokes be placed as close to the hub as possible, is this right?

Wireless bicycle computer on a Brompton

Dave Horne, Aug 1997:
Who makes a wireless that can work with 16" wheels?

Wireless bicycle computer installation

David Cox, Aug 1997:
At the risk of sounding really thick, does a front pannier full of stuff inhibit a wireless computer ? It is 35 years since I did O level physics and the empirical test would be a bit expensive.

Bottle cage

Doug Faunt:
Any suggestions for mounting a bottle cage? I'm thinking about trying to positions one on the steering post, so it'll still fold.

Horns

Clive Page, Dec 1997:
Does anyone have a suggestion for what the law calls "audible warning of approach" (around these parts). Ideally it should be loud enough to penetrate the cab of a 40 ton truck (or a sports car where the in-car entertainment system is going "thumpa-thumpa-thump" at full blast) when they are still over a hundred metres away.
For a time I had an old style hooter with a rubber bulb, but it was hard to mount it so it was easy to use without fouling the folding of the handlebars and eventually the reed got corroded and lost its voice.
More recently I got a battery-operated device called the "Megahorn" which emits a high-pitched shriek (not unlike the warning noise from a reversing bus or truck). It's almost deafening when used indoors, but outside it doesn't even bother some pedestrians as they step off the kerb without looking just a short way in front of me. And recently I've found several cases in which I was in danger from motor traffic where the driver didn't notice I was there. So obviously I need something louder.
A horn for a motor-cycle might be loud enough, but I'm not sure where one could be fitted while keeping the bike foldable (and I don't know how much power they take). I'm not too worried about weight, as I try not to carry my bike folded more than short distances.

Air Zound 2

Dog deterrents

Mirrors


Quick repairs on the roadside

Repair toolkit

Lucas Fletcher:
I would like to assemble a toolkit that makes sense for the Brompton. Can everyone list the "must have" tools to perform all possible roadside service?

Mini pump

Pre-2000 Bromptons

Peter Lawrence:
There was nothing wrong with the pump as such - but I couldn't unscrew it fast enough to avoid all pressure leaking out. In the end I could only use the pump to detect leaks and I had to use petrol station air to pump up the tyres for real use.

MK3 Brompton's mini-pump

Alternative mini-pumps

Avoid car pumps

Nico J. de Boer, Aug 1998:
Since Bromptons by default come with car-type valves, I thought the idea to use an automatic car pump might be too obvious,
[...] I put the dial of this car tyre machine at 55 psi, and then the tyre wall already separated from the inner steel cord (probably this machine was ill adjusted?).

Fixing punctures

Changing tyres


Beautifying a Brompton

Mudguards

brammonique, Jun 2000:
I am an avid user of the brompton T3, and I like the looks of the bike's design (all black), but there is one thing I hate to look at. And that is the incredebly dull looking gray/silver mudguards . I like to replace them for some carbonfiber look black ones.
Is there anyone who knows where to get them?

Damaged Brompton sticker

Mark Maier, Aug 1998:
My Brompton sticker on the main frame was damaged severely so I took it off. Now the bike looks nice and "clean", but I started getting questions like "Is this a Brompton?" with a sceptic glance I interprete as "Is it stolen?" so I am thinking about putting it back on. Is there any scource for these stickers? If possible, I would prefer it smaller than the standard +/- 30 cm long one...

Paint job

National colours

Nico J. de Boer, Aug 1998:
It appeared that blue+black is a custom colour in the UK, while it is one of the "standard" colours in the Netherlands. The Dutch "special" red+black edition of my girlfriend happened to be a "standard" colour in the UK! [...] UK standard colours apparently are all black, and red+black, the Dutch are blue+black and red+white.

Frame numbers

The frame number is on the little platform linking the seat tube and the rear triangle hinge.
S.J.Canfer, May 2000:
BS6102 is the British Standard for cycles.

Warning! There's no way back after this!

Anything you do to your Brompton is likely to void warranty on the entire bicycle, even if there is no causal relationship between your modification and the failure your Brompton suffers lateron.

Caution: think before you tinker

Channell's bike

Channell Wasson, Oct 1999:
It started out 5 years ago as an L3 bought in London in a fit of instant enthusiasm for the design and fine workmanship. I had been riding Moultons for the prior 20 plus years. Mine has every variation I have been able to come up with. After a year I converted the bike to a complete T5 model. (not a recommended project). I then started experiments with front derailleur systems. On mine I currently use three chain rings on front, but there are chain length problems and chain alignment problems at times. The final system which I sell as an add-on kit uses a dual chain ring of 53tt and 39tt. All components are Shimano hi end pieces. It works well and is reliable but expensive, however, I have heard few, if any, complaints. The key to success of the system is the bracket we developed for the front gear changer and cable management. As for brakes I've never had a problem with them, but on the other hand I was always on the look out for better brake pads or brake blocks. The brake mechanisms are a good side pull design that has been used for many years on bikes. However, it is much more difficult to stop a smaller wheel than a 26" or 28" wheel. Eventually I developed our v brake system for front brakes only. It makes a big diference.

For the moment my frame builder, who made this part for me has dissappeared and I must find a new source for v brake forks. My Brompton has served well in daily vigorous use by a heavy rider (215 lbs). I often pull a loaded trailer, Sometimes including my Lab pup Brommie! She rides in the Bykaboose perfectly contented. Over the years I have worn through one rim, cracked a front frame member, (it's made stronger now) and had a crack failure in chain stay member of rear triangle. This was "mig: welded immediately at my favorite muffler shop which was only a block away when this problem occured in San Francisco. Brompton replaced the part with the new triangle which was made stronger as of three years ago. Mine was made before the upgrade. Yes there are improvements going on behind the scenes. My feeling is that these problems could occur with any bike you might own.

Other changes have also been effected by me, but any changes we have made have not been approved or authorized by Brompton Bicycle Ltd.. Anyone that buys custom made changes from C.M. Wasson Co does so at their own risk and peril. The availability and high cost of liability insurance surely limits inovation and forces adhereance to tried, true and approved systems.


Maintenance at home

See also

Removing a wheel

Peter Amey:
If you have to take the wheel off it is not as hard as the manual makes it appear. I do it as follows:
  1. Undo the gear cable at the adjuster - if you do this by slackening the knurled lock nut by the very tiniest amount then you shouldn't lose track of the gear adjustment when you put it back together.
  2. Pull off the black plastic bit with the pulley.
  3. Undo the first wheelnut you find; this will allow you to remove the piece of bent metal which holds the thing referred to in (2) and also the chain tensioner.
  4. Undo the wheelnut now exposed and the one on the other side - the wheel can now be removed. It is not necessary to unscrew or remove the bit of chain dangling from the hub as long as you are careful not to catch it on anything while mending the puncture.
Replacement is basically a reversal of the above but take care:
  1. That the support washers either side of wheel slide all the way into the fork slots and are flat against them.
  2. The bit of bent metal that holds the plastic pulley thingy has its tab aligned with the direction the gear cable must go.
Once the wheel is back on the only thing left is to reconnect the gears. Providing you undid the knurled lock nut the tiniest amount it should be ok to screw the cable back on until it almost touches the locknut and then tighten the locknut against it; this will leave the gear adjustment correct without any special setting up. NB. If you hear graunching noises from the hub or find it switches gears on it own then you must re-adjust according to the manual; however, I have never had to do this using the above procedure.

Rear wheel removal

Removing the rear triangle

Check out Tips, tricks & tinkering - Waggly rear ends before attempting this!

Bike repair stand for Bromptons

How to apply the right torque?

Andrew Brooks, Jul 1998:
The Brompton manual, along with my new mountain bike manual, gives torque settings for various fixings. Can anyone tell me how you set a torque with an Allen key? Is there some special tool?

Adjusting the stearing bearing

Disassembly of the steering column

Ron Colverson, Sep 1999:
This fitting is the same sort of thing that's found on a regular bike that has a normal traditional type of stem. The bolt (which is long) screws into a 'wedge' which clamps the stem (the tube immediately below the hinge) to the steerer tube (the tube extending upwards from the forks). The stem tube fits inside the steerer tube. Not easy to describe, but obvious when you've seen one dismantled.
Before you dismantle anything, draw a picture of where the cables go, particularly which side of which tube they pass. You'll need this when you put it back together, I guarantee!
To remove the forks, first fold the handlebars down to expose the binder bolt but don't clip them. Loosen the bolt about three turns, tap it gently with a hammer to release the wedge and pull the stem tube upwards to withdraw it and the hinge and upper parts all together. You know when the wedge is released 'cos the bolt will drop back down to seat on the hinge casting and be very loose, and you will then be able to twist the handlebars relative to the forks.
Then you can dismantle the headset as normal (this means dropping the ball bearings everywhere) and take out the forks.
If you don't feel confident with all this, I'd say take the manual's advice (don't touch it) and get a mechanic. Still draw the picture though - just in case!

I've taken out the allen bolt to remove the stem - now what? It's as solid

as a rock.

{Susan Mathis, Apr 1999} I'm in the process of installing Channell's new front fork with the V-Brake and I'm having a heck of a time tapping out what I assume is the "expansion bolt" that keeps the steering column attached to the bike. I've loosed the 6 mm bolt in the unfolded steering column. It doesn't clear the frame so the bolt can't be hit directly. I cut a block of wood to fit and really gave it a good hit or two (or 10!) and the bolt hasn't budged.

Headset lubrication (or not)

Spare parts you may need one day

The Brompton spare packs

Channell Wasson, Jul 1997:
Here is a list of items found in the Brompton Spares Pack.
Contents of Main Spares Pack:
  • Seat post quick release fitting
  • Raleigh 16" x 1 3/8" tire
  • Raleigh tube 16" x 1 3/8"
  • Handle bar catch
  • Rear triangle roller
  • 3 speed axle nut
  • Hinge clamp T-bolt assembly
  • Brompton suspension block
  • Cables and housing for front and rear brakes
  • Gear shifting cable
  • Instructions for replacing cables
  • Two brake blocks
  • Rear sprocket (13t)with dust cover, spacers and chain guide disc
  • Instructions for installing rear sprocket and spacers
  • Chain tensioner assembly (complete)
  • Spokes: set of front 14g and rear 13g
Contents of Additional Spares for T models
  • Tail light (with wires)
  • Head light
  • One rubber roller for rear rack
  • 2 elastic cords for rear rack
  • Dynamo
  • Detailed instructions for installing tail light, head light, dynamo and wiring to these items.
Prices:
  • Main Spares Pack $128.49
  • Additional Spares Pack for T models $40.86

Spotlight on tyres

Preventing punctures

Is it worse on a Brompton?

Cause analysis

Airless tyres (Greentyre): a scientific analysis

Summary of cures

Tyre liners (Mr. Tuffy and allies)

Slime

Airless tyres

Tyre pressure

More: Tips, tricks & tinkering - Tyre pressure

Time

Insanity

Bob Gelman, Nov 1998:
I recall a mention of a Mr. Tuffy type of tire liner to help lessen/prevent punctures. It is called SpinSkins (http://www.spinskins.com/spinskins.nsf/). The product is very light. It is only sold in sizes too large for most folders and was not thought to be sizable for folders. I have no experience with the product but I am plagued by "puncture vine", a/k/a Tribulus Terrestris, which is rampant in this area.
The following may be of interest:
Dear Spinskins,
I use a Birdy folding bike which has 18" x 1.5" (80 lb psi) tires made specially for this bike. Is there any way I could use your product on this unusual size tire?
<Spinskins> That's no problem. We do have to give you a special size but we can work that out. Just call our toll-free hotline at 1-888-477-4675 and ask for John. He can make the arrangements for you.
A post of mine to another group suggests an alternative solution to this problem which appears to be quite amusing, e.g., get people to eat the stuff:

I've been doing some web research on the evil weed that plagues many of us in the Western United States with flat tires. Tribulus Terrestris; aka Puncture Vine; aka Goat's Head. I was MOST AMUSED, after seeking more infomation by search engine on Tribulus that it is:
TribolicTM - 250 mg Genuine Bulgarian Tribulus terrestris.
Commonly known as punture vine - A herb used as an European remedy for impotence and as a stimulant that increases libido (sex drive) and sexual performance in men and women. It is also reported that Tribolic (Tribulus terrestris) is the closest and strongest all-natural herbal alternative to synthetic anabolic hormones.
Medical studies showed Tribolic (Tribulus terrestris) significantly elevates the levels of several hormones: testosterone, luteinizing hormone(LH), follicle stimulating hormone(FSH) and estradiol. Further studies showed that when taking Tribulus terrestris in just five days testosterone levels increased by a significant 30% or more.
TribolicTM - Competitive Edge
Bodybuilders and other athletes like the former Soviet union and Bulgarian athletes used Tribolic (Tribulus terrestris) for strength and conditioning. U.S. Olympic coach Dragomir Chioroslan of the American weight lifting team gives his approval for Tribulus terrestris.
TribolicTM - Male Performance
Tribulus terrestris having an effect on reproductive functions: * An increase in spermatogenesis (formation and development of sperm) * Improvements in the quality, mortality and survival time of sperm. * Improves strength of erection.
Dr. Robert Fraser, Researcher and Herbalist writes Tribulus terrestris has no adverse effects on the central nervous or cardiovascular systems and that it is said to have a mild diuretic effect.

The above was taken from: http://www.paramountnutrition.com/

The plant has been well described elsewhere by Jobst Brandt:
The plant is called puncture vine (tribulus terrestris) and it grows primarily on barren ground, ground that has either been sprayed with herbicides or is otherwise bare in arid regions. It does not compete with grasses or other roadside vegetation so it is easy to see. Know thy enemy and I think the major problem of flats will be solved. You can see this plant at: http://www.fortnet.org/CWMA/puncture.htm and http://chili.rt66.com/hrbmoore/Images/T-Z/Tribulus_terrestrus.jpg and http://gnv.ifas.ufl.edu/~fairsweb/images/lh/lhp58.gif

Jobst Brandt


Now, if we could all just eat this plant whenever we see it we could increase our strength, improve our conditioning, enhance sexual drive and improve sexual performance (in both men and women!) AND ELIMINATE MOST OF OUR FLAT TIRES TOO !

Alternative valves

Fat or slim tyres?

Stephen W. Butler, Sep 1998:
If I heeded the masses of youthful riders, who believe speed is the one and only design criterion for bicycles, I would have ceased to be a bicyclist many years ago.
Fat aggressive tread tires are preferable because:
  1. they absorb more road shock,
  2. they are much less susceptible to flats,
  3. they have greater stability in rock and gravel,
  4. they are easier to balance on in near stop condition,
  5. they have less sink in sand and/or soft mud,
  6. for any given distance of travel, they afford slightly more exercise,
  7. they have better start/stop traction on ice or other slick surface.
I also wonder, are fat tires kinder to spokes?

Alternative tyres

Before 2000, there were only two serious contenders: Raleigh Records (all black, fitted as standard) and Primo Comets (light coloured sidewall, almost slick). It seems there used to be Michelin Universal tyres that fitted the Brompton.
The year 2000 brought several new models of tyres: two specially made for Brompton, and a 37-349 version of the Schwalbe City Jet.

Schwalbe

How do the Schwalbe tires fit on the rim?

That is, is it easy to remove and install them?

Brompton Mk3 tyre

Riding feeling

Do slicks slip?

Which one is quicker?

Which one lives longest?

How do they resist punctures?

How hard is puncture repair?

How do they cope with tyre-side bottle dynamo's?

Is there a difference between Primo and Pr1mo?

Tyre pressure

Optimal pressure

Maximal pressure

How does over inflation contribute to rim failure?

Tyre sizes


Spotlight on wheels (rims, spokes and hubs)

This chapter about the solid part of the wheel. Covered elsewhere:

Broken spokes

The problem

Replacement spokes

WheelLengthGauge
front152mm14 (Ø2.0mm)
rear 13 (Ø2.25mm)

The cure?

Rim design: is the spoke angle wrong?

Rims worn out

As on many bikes, the Brompton's rims not only make up a wheel structure. They also offer a surface on which the brake blocks operate.

Some have complained about the rapid wear of their Brompton's rims, and potential accidents when the wheel suddenly "explodes" under the tyre's pressure.

To avoid it: Tips, tricks & tinkering - Basic brake care

Victim's accounts

Explanations (anodized rims, brake blocks etc.)

Alternative hubs

Rear hubs: Tips, tricks & tinkering - Sturmey Archer

Pantour suspension front hub

See www.pantourhub.com, review in Velo Vision issue 10 (June 2003)

Loose/worn front hub

Problem

Cure: adjust for wear & grease the bearings occasionally

Ditch the cage

New bearings

Alternative front hub

Alternative rims

Alternative wheel sizes

Front hub width = 75mm, rear hub width = 115mm.

Building a (small) wheel


Spotlight on brakes

Stock brake effectiveness

In the early years, CLB brakes were fitted until supply dried out. From around 1996 to March 2000, the Brompton came with Saccon City 2 brakes. Since then, a brake is custom made for Brompton and can be retrofitted to older models.

How to improve brake power?

Brake blocks

My '96 Brompton Owner's Manual suggests Saccon PT 205 brake blocks. My '96 models came with Saccon 176 A brake blocks. '98 models come with Saccon 400 blocks.
According to many, the early blocks are or become too abbrasive and could cause rim failure (Tips, tricks & tinkering - Rims worn out), unless regularly cleaned. This probably depends on local road condition: dirty, muddy, wet cycle paths.

Alternative brake blocks

Brake cables

Break not brake (old models)

Quite a number of reports on cables breaking at the pear-shaped nipple. This problem is solved in the Mark 3 Bromptons and brake upgrade kit introduced in March 2000. The new brakes have barrel type nipples.

On these old Bromptons, you may want to replace the handles to upgrade to barrel nipples.

Replacing the brake cable (old models)

Andrew Brooks, Oct 1997:
[...] spent an incredibly frustrating hour poking the brake cable ends up into the levers trying to get them to locate into the brass swivelling slotted bit inside. It's just impossible. Both times I managed it but only when for no apparent reason it just sort of clicked in to place. And only after me having been right on the brink of trampling the whole bloody machine into flatness. There MUST be some technique to it. It just can't be that difficult.

Replacing brake cables (new models)

Peter Amey, Dec 2004:
There has been a small ripple of messages on uk.rec.cycling about brake cable inners for the B. Following applies to dual pull calipers as currently fitted (or in my case as upgraded).
Someone asked about the length of the barrel on the cable end that fits the brake lever - he had bought some that were shorter than the originals. So had I and it bothered me. FWIW, I have checked with the Brompton factory and they confirmed that the barrel should be long enough to engage in the side plates of the yoke attached to the brake lever. Typical cables brought from bike shops have shorter barrels that slip down between the side plates and put the pulling load into the piece of metal that bridges them; loads that this piece of metal is not designed to take.
Worth bearing in mind if you are buying replacement inner cables.

Alternative brake handles

Alternative brakes

John Blackburn, May 1999:
What I would like somebody to explain is why some types of cable-operated brakes are claimed to be better than others. There are only three things to consider:
  1. The mechanical advantage. The term is used here in its engineering sense - the ratio of the movement at the brake lever to the movement at the block. For example, if the lever is moved 20mm and the block moves 5mm, the ratio is 4, which means that the block is pressed against the rim with 4 times the force that the hand exerts. This is a useful improvement.
  2. "Stiction" - general friction and stickiness in the cables, pivots
  3. The accuracy with which the brake can be adjusted. For example, if the blocks could be reliably located 1mm from the rim, then a mechanical advantage of 20 could be used (a 20mm pull at the lever would move the block into contact). This is complicated by the fact that the block is compressible.
So, instead of merely asserting that one type of brake is better than another, I would like to know WHY it is better.

Better calipers?

Stein Somers, Mar 1999:
It has been claimed that the Alesa caliper that used to be fitted to Bromptons was better than the current Saccon. I wonder how? The mechanism and leverage is identical. It's not that the caliper legs were freewheeling on ball bearings and are stuck with glue now. Isn't the cable much more of an issue?

Dual-pivot brakes

Fitting the Brompton dual pivot brake upgrade

V-brakes

Magura hydraulic rim brakes

Joerg Scheiner, Oct 1998:
[...] my local dealer told me the Magura oil tubes are not designed for daily bending that happens when folding the Brompton and thus will break and leak very early. Is this true?

Coaster brake

O'Reilly, Peter, Mar 1999:
Coaster brakes being the ones whereby you apply pressure to the pedals in reverse to brake and are commonly used for single geared bikes. I have one on a 3 speed (Shimano hub) tandem bike and it brakes reasonably well to me. Rarely do I use the front brake lever for the drum equipped brake.

Hub brake

As for hub dynamo's (Tips, tricks & tinkering - Hub dynamo (BromSON)), the front fork measures only 70mm compared to the standard 100mm or more. Standard hub brakes won't fit. Sturmey Archer does mention 70mm hub brakes, but they refer to the diameter!

Changing brake cable routing

The Brompton brake cables enter the caliper upside down. This makes the cable longer and there's concern this allows water to penetrate into the outer cable. Some candidate replacement brakes don't allow the cable to be routed this way. So why wouldn't you change the routing back to normal? And why and how would you change it?

A little modification I made to keep water out of the brake cables

Erwin de Vries, Jun 2000:
When servicing my B. I noticed some rust on the inner front brake cable, in the bend where any water that gets into the outer cable will collect. This can happen easily, as has been pointed out before, because of the upside-down arrangement of the brake cables.
At my local bike shop I found small plastic and rubber thingies made to keep water and dirt out of the brake cables on mountain bikes. As you know on many of these bikes bits of cable with and without outers are interspersed, so there are lots of places where water can get inside the outer cable.
This device consists of a tubular bit of plastic that fits over the end of the outer cable, and then narrows to a diameter slightly larger than the inner cable. The inner cable runs through a narrow gap in a rubber bit, which fits, but freely moves, over the narrow end of the plastic bit, thus keeping the water out.
Through my lack of knowledge of bike-tech English, this might be somewhat hard to understand, but any decent bike shop that sells mountain bikes will sell this item, and once you see them, it is immediately obvious how they are to be installed (if not, I could be persuaded to take a picture and send that to those interested).

Getting the brake clearance equal

Chris Newport, May 1999:
Invariably I find after adjusting a caliper and then applying the brake that the clearance on each side is unequal.
Is there a way to align and then fix the return spring so it applies equal force to both sides (and stays that way)?

Do the 'toe in'


Spotlight on lights

There's plenty of information about bicycle lights on the net, including Andrew Henry's Bicycle lights FAQ. However the Brompton's compactness imposes some limitations with respect to other bikes.

What lights to I need - overviews.

Front light

Space beneath the panier is 90mm, enough for most lights. Brompton fits a simple, effective, lightweigth Soubitez. I have replaced this with a halogen Axa Hilight myself.

Front light and standard pannier conflict

How visible is the light while the bag is fitted?

Front light lens falls off

John Yeates, Sep 1997:
[...] the front pannier frame seems to rub against the front light somewhat, causing the cover to come unscrewed - it's fallen off three or four times already!

Rear light

Front spotlights

Electrical power supplies

Battery power

Batteries versus original Brompton lights

Rob Cope, Jan 1999:
I still have the lights fitted, alongside battery/LED combination. Has anyone experience of running the supplied system off batteries?

Tyre-side bottle dynamo power

See also Tips, tricks & tinkering - How do they cope with tyre-side bottle dynamo's?

Axa IQ

This is the standard T-model's dynamo since around '97.

Axa HR

Nordlicht dynamo

Busch & Müller Dymotec S6

http://www.bumm.de/index-e.html

LightSpin

Rim-side bottle dynamo

Bottom bracket dynamo

Hub dynamo (BromSON)

Willi Mindak, Sep 98:
Is there a hub dynamo that fits the Brompton, or is the space between dropouts too small? All hub dynamos I came across need 110mm between dropouts, and the available space is only around 90mm.

Dynamo charged battery backup

Wiring

Where to mount a bottle dynamo?

A T-model (The first steps to folding wisdom - C or L or T model) is equipped with a dyanmo mounted on a purpose added stay on the rack (a rather weak stub)

Slipping tyre-side dynamo

Auto-engaging bottle dynamo

Doug Faunt:
I've noticed another deficiecy with the stock dynamo, too. It turns itself on, sometimes just riding down a bumpy street.

Blown tail lights


Spotlight on the seatpost and saddle

(Mis)using the saddle adaptor pin

Robert Payne, Nov 1999:
The Brompton owner manual says not to put the seat adapter on pointing to the rear of the bike. Has anyone tried this anyway? Any damage to the bike?

Keeping it up

So now we have a seatpost extracted to the right heigth, how do we keep it there? Depending on your weight, the weather and the way you open tincans, it has a tendency to gradually slide down the frame as you ride.

Is tightening the quick release seat clamp bad?

Getting it up or down

David Cox, Mar 1999:
The Brompton owners manual says never put lubricant on the seat pillar and I have found the pillar slides down gradually if you use WD 40 to clean it.
However, I have now twice been embarrassed to find that my Brompton would not unfold because the pillar has stuck. The problem relates I think to getting the bike a bit gritty on the canal towpath and then putting it away wet.
I struggled to raise the saddle the other day [...]. The natural temptation is to swivel the saddle to try to get it moving. The basic problem is that the plastic sleeve in the frame has moved so that its gap no longer meets the gap in the frame. I managed eventually to yank the pillar up and because it had to perform several more times that day I went straight to a motorcycle dealer and sprayed it with a lubricant !
I have now taken the pillar out (I had to use another pillar as a drift and a rubber hammer) cleaned everything up and moved the sleeve back into position. It seems to work OK but a Brompton that wont unfold is a very frustrating object.
I rang Neil Gascoigne at Gascoigne Bros in Olton to order a new plastic sleeve. He said that to fit this the whole bike had to go back to the factory for a new sleeve to be reamed and glued in. Apparently even dealers dont have the kit to do this.
[...] A precaution for Bromptons used in all weathers is to keep the pillar clean (but not lubricated) and perhaps dry it when folding the bike. Swivelling the pillar once is gets stuck aggravates the problem.

Crunchy sound while retracting the seatpost / stuck post

Removing rust spots from the seat post

Osbert Lancaster, Apr 98:
I've got some rust spots on the seat post. Probably caused by riding in pouring rain then folding the bike and not riding it for a few days - so the seat post didn't dry off properly.
How can I clean the seat post and get rid of the rust - and prevent further spots? The manual gives dire warnings about putting oil anywhere near the seat post.

The rubber bong: an invention to keep your seat post clean

A wish by Peter O'Reilly and a suggestion by Ka Lun Tam, led to this invention:

{Erwin de Vries, May 2000} Here's how I closed the underside of the seat tube from water and dirt getting in:
I took a conical rubber stopper, the top of which just fits into the seat tube, and inserted it into the seat tube. I then marked it and cut off most of the rubber protruding from the seat tube, and attached the top of the stopper to a short piece of cylindrical rod *, which just fits into the seatpost (diameter approx. 1mm smaller than the inside of the seatpost). A bit of elastic cord** is attached to the rod, and to the top of the seatpost. The elastic should be tight enough to keep the rubber stopper against the seatpost when this is lowered below the frame. When the saddle is raised, the elastic is stretched, and the rubber stopper is drawn against the underside of the seat tube, keeping dirt out. The bit of rod is rounded off at the top, so that when the saddle is lowered, the rod easily enters the seat tube. Because the stopper is only marginally wider than the seat tube, it doesn't get caught anywhere in the Brompton Triangle, and even passes the LSD without problems.
There are a few things to be borne in mind though, if you attach this thingy to your Brompton (I imagine this could also work for other folders):

*Actually, I sacrificed the top of my old broomstick, when I found how neatly it fit into the seatpost (ever heard of Chuck Yeager? ;-) . [Later...] And that's where I went wrong, so I'd like to warn you. I thoroughly washed the bike, causing the bit of wood to get wet and therefore EXPAND while the bike was folded. It got stuck in the seatpost, and I had quite an enjoyable time getting it out so I could unfold the bike again (of course this didn't happen at home where I have all my tools) I've now replaced the wood by a bit of PVC rod. That won't get stuck unless I blow hot steam down the seatpost I suppose ; )
I don't think the length is very critical; on my bike it's about 1 inch.
**I didn't use a spring, fearing it'd make clanging noises inside the seatpost when riding over bumpy terrain. Apart from getting stuck, the stopper works beautifully. No more scraping noises from the seatpost when (un-)folding the B.

Replacing the seat post's sleeve in the frame

Keeping it straight

Telescopic seatpost

Andrew Brooks:
What is this and how does it work? My image is of something like a radio aerial with a quick release at each junction - something a bit flimsy and swaying and a nuisance to put up and down.

Adjusting the seat post after unfolding

Rail saddles on a telescopic seatpost

Telescopic seatpost versus long seatpost

Can one shorten a Brompton seatpost?

There are three reasons to do this:
  1. The telescopic seatpost needlessly sticks out ± a centimeter at the top of the folded package, and scrapes the ground on the bottom.
  2. The flare at the bottom of the lower or only tube, which keeps it from being raised to high, also makes removing the tube - for even more compact folding or cleaning - difficult; it has to be guided through the bottom after the clamp or saddle on top has been removed.
  3. Taking off a tiny bit (±20g) of dead weight.
With a cheap small blade I sawed off a ring. I sawed a tooth and bent it outwards as a replacement for the flare. Just bending the tooth a bit it not enough: it gets bent back each time you raise the tube. I had to bent the tooth 90 degrees outwards and cut off most of it.
An unforseen fortunate effect of replacing the flare by a tooth was that it now allows the tube to be taken out easily from above. I just turn the tube to where the tooth fits in the gap in the frame's clamp (the gap allows for the quick release to tighten the clamp around the tube).

How to make your own telescopic seatpost!

Len Rubin, Nov 1999:
Seatpost diameter is 1-1/8" (or 31.8mm) Custfold:
I obtained some thick walled s's tube, exactly right for the post diameter, and with a large steel 'cannonball' bearing ball and 7lb hammer, [later he wrote: a 4" ball and 14lb whack] belled the end out to match the Brompton original. This tube was cut to fit just above the frame when the bike is folded, and a cannondale MTB clamp used to hold the USE shimmed seatpost for the top 12" extension.

{Custfold, Aug 1997} [Second stage is a standard 1" seat tube] - the first version of the extending seatpost - my concept to accommodate a 6'6" rider with 38" i/l (I ride a 29" frame on a standard bike, with bars and seatpost well out), I found that the USE seatpost system offered a 1" seatpost with shims up to 1.25" at least.
My reason for the seatpost was 3-fold (sorry)
1) With the Mk 1 extension (a cut down seatpost, with a q/r clamp from the Bickerton on the top section of a Brompton seatpost) the leverage bent the top back & forward until it snapped off,
2) The weight & leverage on the standard tube size bent the seatpost, where it enters the frame, and made the post stick.
3) The saddle adjustment (normal grip plates) could not be kept tight, or adjusted finely enough.
USE are 2-bolt micro-adjust posts, up to 18" long, and some versions even have internal suspension. I got a sample length of 31mm (1.25") stainless tube, with generous wall thickness, and a USE shim fitted perfectly, as well as the tube fitting the Brompton perfectly. To use a seatpost larger than 1" does not give enough 'meat' for the clamp/shim in this style, so I expect that Brompton found a similar problem, and fittings are available for 1" seatposts.
Caveat with USE. The adjustment for Brompton 'frame' angles is on the limit, and if the seat starts to creak beware. One of the bolts will soon fail through fretting fatigue - catastrophically (ouch), and you have to ride home with no saddle, or do him big buggerup repair job
PS a USE rig is expensive (in the UK) c.UKP40 for the post & shims and a cheap clamp. Specialised 1.25" clamp c.UKP20.

Alternative seatposts

Ultralight Titanium seatposts

See also Len's Ultimate Folding Bike project (Tips, tricks & tinkering - Leonard Rubin's UFB ("Ultimate Folding Bike" or "Super-Brompton") project). Leonard Rubin:
The seatpost has an integral, very robust, quick-action, micro-adjust head, permitting very fast saddle removal, while retaining angle adjustment, for airline overhead baggage stowage! It is available in any length (within reason, of course, for practical and safety considerations), and two wall thicknesses. The strength-to-weight ratio of Titanium is phenomenal, and it will never rust, corrode or become horribly scratched, as with other post materials.
The weight savings over the original Brompton steel posts range from 125g to well over 250g! Combined with the saddle upgrade, this can easily save a pound! Also a much greater range of fore-aft adjustment is possible, and in most cases, that heavy, scary extender gizmo is no longer needed (saving even greater weight savings.)
As an added benefit, titanium is naturally springy, resulting in a more comfortable ride! The prices range from $100 to $115, depending on length and wall thickness. Your inseam and weight will determine exact specifications. I can make these for Moulton owners (and others) as well.

Carbon fibre seat post

Comfy saddles

Alasdair Baxter, May 1999:
Being somewhat heavy, I find that the original saddle becomes quite painful on the nether regions after a few miles. This is doubtless due to the concentration of my great weight on a relatively small area of my body.

Terry

Brooks


Spotlight on handlebars

Broken handlebars

Victim's accounts

Theories

The different faces of Aluminium (scientific)

Given that handlebars and rims are both aluminium, why are there relatively many instantly broken handlebars, while rims, subject to the same forces, even weakened by abbasive brake blocks, are so reluctant to give up in a streak of death?

Cures

Alternative handlebars

Rotating the handlebars

Bar ends

Ka Lun Tam, Feb 2000:
Bar ends refer to additions made at the end of mountainbike ( or other straight) handlebars. Essentially, they are extra lengths of handlebars that point forward at the end of the handlebars, giving the cyclist more hand positions with which to ride.

Handgrips

Twist-grip or other gear changer for the 5 speed hub

Stem (steering column) failure

The breaking of a Brompton's front stem appeared in a tale of horror (Treats to ride your imagination wild - Catastrophic failure of Brompton in traffic). Here's useful information from the discussion that followed:

Spotlight on the (hub) gears

See also:

Sturmey Archer

Brompton's have either a fixed gear, or a 3 speed (SA-3) or 5-speed (SA-5) Sturmey Archer hub gear (The first steps to folding wisdom - 3 or 5 gears).

Jane Thomas, Mar 1998:
I've also got a lot more info from the nice man at Sturmey-Archer, and have added servicing information for the 5-speed hub to my webpages.

Malcolm Lyon:
I can recommend an excellent book on the history of them by Tony Hadland called 'The Sturmey Archer Story ' ISBNO 9507431 3 5. It was published in 1987 [by Cycling UK] but does not cover the latest Sprinter hubs but it is an excellent reference book.

IHPVA discusses hub gearing, and Sheldon Brown 3 speeds.

Custfold, Oct 1997:
[...] an SA 5 star dealer was at hand when my hub s/d'd and having a dud wheel with a good hub, I went in to ask for a switch - either the guts, or build the good hub in the good wheel. The units were an SA 5, and a 5-star which I now know have incompatible guts, and would have expected the SA trained LBS to check for/know before doing the swap. So remeber there are at least 3 types of 5-speed SA hub you can have in your B
The system lasted about 1 week, and then seized solid because the pawl sizes were slightly different. Needless to say the mechanic got his ear chewed very hard. So even with Shimano Approved Dealers (SAD LBS?) and other nice decorations it is still caveat emptor in the service dept. Andre Phillips, Dec 1997:
I have just received a nice letter from Sturmey-Archer in Nottingham, advising me of their Australian agents. In fact it's the address of the Sturmey-Archer importer who also has a knowledge of who's who for gearbox servicing in Oz. The Downunder Sturmey-Archer agent is:
British Trading International Pty. Ltd.
69 Powers Road
Seven Hills, NSW 2147
ph: (02) 9674-4566
fax: (02) 9674-3854

Gear calculators

Is it normal to feel a lot of resistance pedaling backwards?

Robert Payne, Feb 2000:
I realize this is not a huge problem since I spend 99.9% of my time pedaling and riding forward, but...
On my T5 the chain encounters a lot of resistance when pedaling backward. The resistance increases as I go up in gears. In first I can pedal backward without problem but in fifth the chain gets all bunched up.
Also when I roll my T5 backwards the pedals move in a jerking motion.
Could these be signs of any particular problem or are they common/normal with the SA hub?

Hub gear troubleshooting

What to do when gears don't seem to work properly? Typical problem reports involve: first gear not engaging while shifting down from third or higher gear, first gear engaging allright but slipping when pedal force is reduced, horrifying crashing and grinding noises, or worse (like Treats to ride your imagination wild - Savi's SA-5 saga).

Adjusting Sturmey Archer hub gears

The funny roller thing

I.e. the selector guide system according to Sturmey Archer or the guide roller GRA according to the Brompton Owner's Manual.

Custfold, Oct 1997:
I has a Sprinter 5-speed, and the changer uses a split slider system with 2 springs to make the relevant dog clutches move in sequence. This is very fragile, and I much preferred the simplicity of the 2 cables. I broke mine fairly quickly, but not before experiencing some hiccoughs with the gear change.
The seating of that funny roller thingy, cruuuucial. and if this is misaligned (and on a B this is easy to do or have done with a slight knock) then the indicator rod will not run smoothly, and can become bent - my gears packed up partly through the rod sticking, because it had become bent, because the roller thingy got knocked and put a bend on the indicator... stil eventually the sliding dog completly fell apart [...]
the main reason for the roller thingy - the pull on Sprinter is much longer than a normal 5-speed, so the rod comes out further.

Hub gear breakdowns

Failure design

R.E.Burton, Sep 1997:
Why are hub gears so designed that when the control cable or toggle chain breaks one is left in top gear which is unpushable rather than bottom gear which would always allow one to get home however slowly?

Hub internals explained

7 or more speed hub gears

Hub gear efficiency

Why is highest and lowest gear in a 5 speed less efficient than highest and lowest in a 3 speed?

Lubrication

1 speed

Custfold, Nov 1998:
My favourite Brompton to ride of the fleet is the 1 speed with gearing around 70 inches (61-14). It is actually a bit undergeared for my liking but no- one's offered a 64/65 ring yet and that is about the limit on size before the front forks foul the ring.
1 speed has shed around 3 lb from the bike and the complexity of another cable, a trigger etc and it has minimal loss from hub inefficiency. Ideally of course I'd ride 61-13 fixed but the Brompton doesn't work with fixed gear ... unless you get the chain setting exactly right in the unfolded state, that would get rid of all unsightly cables between front & rear frames, about 10 oz of brakes and a brake lever. The 1 speed like the 1 speed Micro is a light and joyful machine KISS as they say. In riding a lighter bike the effort to climb hills and accelerate is less so you can use higher gears.
BTW note that in fixed one tends to be able to ride higher gears due to the assistance of inertia - my standard bike on one of 3 frames has a 100" fixed gear, and rides up all but the worst hills.

5 speed versions

Today's Sturmey Archer 5 speed is called Sprinter and has a single cable. Before there far the 5 Star...

Spotlight on the rear sprocket

Jammed sprocket

Megan Lynch, Sep 1997:
I noticed that the thin aluminum ring that separates the back chainring from the hub had gotten bent. In fact, it had gotten severely bent. The chain had actually gotten back onto the chainring again, but it had a third of the aluminum ring between it and the chainring!

Replacement rear sprockets

Lighter

Bigger

Turning a 5 speed into a 10 speed

John, Jan 2004:
Further to my previous postings regarding conversion of Sachs 3 speed to Sturmey Archer 5 speed with two sprockets to make 10. I have done it. It works.
Ingredients required.
How to do it.
Take a 15 or 16 tooth Shimano cassette ring and mark three lugs which match the Sturmey Archer sprocket tabs. File away all the others. File to make fit the S/A hub (the) three remaining tabs. Fit to S/A hub. Remove the FIRST cog (it must be the first. This will be a 13 tooth. File down the tabs as mentioned above-much harder as this sprocket is hardened. Fit to hub. Now make sure the chain which must be a narrow deraileur type fits OK. Now fit the wheel into the Sachs Brompton. Fit 5 speed lever, set up as usual. Now make sure the dual cog shifter shifts correctly-if not adjust as per Brompton instructions. Hey presto a 10 speed Brompton without the need for a front changer and dual chainrings. Gear ratios now are:- 35-40-42-48-53-61-67-77-79-92. Congratulate yourself for all your hard work.

Pictures to show the finished item are here www.pbase.com/john28july. Look at 'Latest pictures section'.

Is it normal that the sprocket looks loose and wobbles?

Rear derailleurs


Spotlight on the chain

When to replace the chain?

Willi Mindak, Apr 99:
When is it time to replace the chain? Is the damage to sprockets/ chainwheel a result of a worn (lengthened?) chain, or is the chain worn because of wear to sprockets and chainwheel? Should one replace the chain more frequently, or is it best to replace the whole drivetrain at the same time?

Chain lubricants

White Lightning

Chain falling off while riding over bumps or while unfolding

It's not often reported, but is no fun to put the chain back.

What to do when it happens

Why it happens and how to avoid it

  1. Is the chain lubricated? Check for stiff links.
  2. Phil Gough, Jul 1999:
    I have known mud and crud buildup on and around the sprocket to lift the chain up off the teeth of the sprocket. But you have to really neglect cleaning the bike to get it this bad.
  3. Chain is strechted or simply too long for the current chainring and sprocket. When the Brompton is unfolded, the chain tensioner arm shoud be almost horizontal, slightly downwards. Replace the chain if it is stretched 1% (unless you have your own chain replacement policy). Check if you could remove a link from the chain while the bike is unfolded (the maximum chain length required is when you start folding the rear wheel assembly).
  4. Can the chain tensioner (the arm with idler pulley) rotate freely, apart from the spring force?
  5. Is the chain tensioner properly seated? Are all chainwheels in line? Sprocket spacers assembled in the right order?
  6. I've replaced the standard 13 tooth sprocket with a 14 tooth (see Tips, tricks & tinkering - Replacement rear sprockets). Now the idler wheel is so close that it seems the chain cannot jump off there at all (but someone claimed it did). I couldn't notice the slightly reduced gearing, which really was too high anyway.
  7. David Edge, Oct 1998:
    If all else fails you can buy 'half' links to tweak the tension.
  8. Phil Neff, Nov 1999:
    After dirtying my hands numerous times, I decided to let Channell, the USA distributor, see what he could do. Though he could see nothing amiss, he replaced the chain and chain tensioner and I haven't had the problem since. Channell charged nothing!

Chain skipping in snowy/icy weather

Narrowing down to 1/2 x 3/32 chains?

Super link in the chain

Richard Lighton, Jun 1999:
The instructions on chain replacement say:
"The joint in the chain must be made without using a link/spring clip."
Is there any objection to using something like the Craig Superlink?
http://kato.theramp.net/craig/slmain.html

Guarding the chain from road spray or yourself from greasy chains


Spotlight on the front chainring

Does the Brompton use a special crank, or can I find a suitable replacement at any decent LBS?

Is the chainring integral to the crank, or can I replace just the crank arms?

What special tool or tools do I need?

Is there also any routine servicing I should do while I have the crank arms removed?