Page last changed December 28, 2004

Spotlight on the (hub) gears

• Spotlight on handlebars - Twist-grip or other gear changer for the 5 speed hub

Sturmey Archer

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

• Bob Gelman, Aug 1998:
  For those of us with weird (?) wheel sizes like 16", 17", 18", 20" who are frustrated by the lack of gearing charts for wheels other than 27", there is an excellent automated program online at :
  http://www.arachnoid.com
  Look for bicycle analyzer on the left side of the title page.
• Gear calculators and much more at http://www.machinehead-software.co.uk/cycling.html

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

• Probably related to this, is that while coasting there's more intense ticking in high gear than in low gear. On a 5 speed, coasting in 2nd gears is most silent and drags less (verfied in Riding issues - Rolling resistance tests).

Hub gear troubleshooting

• Somewhere after 1998, the 5 speed was equipped with a ball-locking mechanism. It can be recognized by the blue ring on the indicator chain, as opposed to the red ring on older models. This make quite a difference with respect to troubleshooting.
• Don't forget you have to stop pedaling or even backpedal an inch while shifting down
• Spotlight on the (hub) gears - Adjusting Sturmey Archer hub gears
• Cabling:
  • Graham A. Patterson:
    What you describe looks like uneven wear, which could be due to a slight mis-alignment in the cable and the cable guide on the axle.
  • Channell Wasson, Oct 1997:
    [...] may be resulting from a kinked cable. I had a similar problem once and solved it by changing the cable. I used the same cable housing though after I made sure it was clean. Then I lubricated a new cable and installed it making sure all was properly adjusted per Sturmey manual instructions for Sprinter 5 Speed. That cured my problem then.
  • Alan rowe, Mar 1999:
    I have found that the gear cable, along with the brake cable have split the outer plastic casing where they fold around the rear hinge. This means rain & salt & rust are able to get into the cable, and consequently shifting is impaired. The real problem with this is that the cable does not move the same amount consistently, and this is essential for operation of the hub. The solution is to replace the cable with one of good quality, and keep it well lubed. When changing the cable, also check that the rod which runs into the hub is free to move, and not obstructed with any grit, and re-grease if necessary.
  • Jim McLaughlin, Jul 1999:
    I read on a Sturmey-Archer web site that Sturmey hesitated to go with a single shifter on a 5 speed due to the stronger spring return pull required. I believe that the longer cable casing on a Brompton adds enough stretch to cause it to pull out of first more than on a conventional bike with short cable casings and a pulley. Before I switched to a coated cable (maybe teflon or goretex, I'm not sure what my mechanic put in) I used to just keep my thumb on it in first. But now I can back off on the adjustment enough that it pretty much stays in first. Maybe a good greasing would do as well as the coated cable wire.
• Indicator rod:
  • Mark James:
    I discovered why my gears were dodgy for a while. It was a couple of twisted links in the SA thingy that goes into the hub, so take care when you adjust the gearws or else you end up not getting good changes and no first gear.
  • David Hansen, Mar 1998:
    While negotiating one of the dafter so-called access controls in Edinburgh yesterday, I bashed the right side of my rear wheel against a large lump of metal.
    My gears did not seem right despite some fiddling yesterday and this morning. I seemed to have lost a gear.
    It was only this lunchtime that I realised what is wrong. The indicator rod is bent at the end and so will not slide properly into the gearbox. This prevents fifth gear being selected and I'm stuck in fourth.
  • Custfold, Mar 1998:
    
    1. Yes you can bend the rod back - my rods frequently bent on the Sprinter hub because they have to travel so far out, and lack the chunkiness of the old AW style rods.
    2. Most common failure is however the pull chain. The Sachs system of ratchet clasp to adjust and much less flimsy chain (and 1 link more) can be adapted by removing the chain from the rod and 'screw' and re rivetting to SA parts. The Sachs' rod will hovever fit AW hub, so only the screw needs changing, unless you decide to switch totally to the Sachs system.
    3. The thread of the sliding dog to which the indicator rod is attached is if I recall correctly 13 or 14g spoke threaded - hence the useful get you home option of screwing in a spoke, and bending it to lock into a lower gear, if cable of indicator fail
    Dave - who is far more pleased with his Shimano where the gear cable stays connected permanently, and if you use a friction lever, can be disconnected without major re setting issues anyway.
• Alignment of the GRA: Spotlight on the (hub) gears - The funny roller thing.
• Anthony Cartmell:
  Are the wheel bearings on the hub loose? Try to rock the wheel sideways on its axle. If there is any play this can also cause Sturmey hubs to slip between gears, even if the gear cables seem to be adjusted correctly. To fix you will need to remove the wheel and re-adjust the bearing cones.
• Peter Amey, Jul 1999:
  I rebuilt [the hub] about 6 months ago changing the selector key and a few pawls which improved it markedly for a while but it has started again.
• Phil Gough, Jul 1999:
  Generally pawl wear is indicated by slipping under high load, and being OK when just doddling along. This suggests that It is possibly the dog clutch which is disengaging under light load, which on the old twin cable type which is what I have been using for many years, would be caused by too much tension in the left hand cable or somehow sticking due to inadequate lubrication or weakened low gear clutch spring.
• Ted Lawson, Jan 2000:
  I was climbing a steep hill on my 1996 T5 just before Christmas when the gears started slipping something terrible. Changing gear made no difference. Back on the flat, the bike was just about propellable but any significant load and there'd be a horrible grinding noise from the rear and we'd slow to a halt. The chain path was ok and everything external looked fine, so I assumed the Sturmey Archer had packed in, and phoned up our local Brommie dealer, Bicycle Doc, in Rusholme, to order a new back wheel.
  Two weeks passed Bromptonlessly - which, annoyingly, meant staying sober during the New Year celebrations, because I had to drive, rather than cycle, back home afterwards.
  The wheel came, but without a cog, so I set about transferring the one from the old wheel. It was then I noticed that the cog had a radial spit in it. Never in many many years of bicycling had I seen such a thing. Cogs with missing teeth, cogs with their teeth worn down to stubs, but never a cog with a spit in it. And it turned out that it was the split, allowing the cog to expand and slip round the Sturmey Archer axle, and not the Sturmey Archer itself, that had caused the problem.
  Bike Doc fitted a new cog straight from their stock to the old wheel in 30 seconds, for about 3 gbp, i.e. 1/30 of the price of the new wheel.
  Moral: don't jump to conclusions, especially about Sturmey Archers, which must rank as the most robust piece of complex bicycle technology ever invented.
  (Bike Doc, much to the credit of their reputation, took the new wheel back, refunding the full cost, though they would have been perfectly entitled to keep the deposit.)
  • Custfold, Jan 2000:
    The 13 tooth cog used to ger up the brompton is particularly prone to fracture - I have broken 4 or 5 in the 11 years of riding Bromptons, as size which is usually used for smallest is 14 teeth. The failure is a pig when it happens, but often one can limp home with the gear skipping on the flat/downhill and just walk up hill.
    Changing a cog is easy provided you have spring steel thumbs and a screwdriver of appropriate size, to flick the circlip out and back in - the hub body is rarely damaged.
    You can usually see the split as the cog is rotated by backpedalling to inspect it
• If all fails, perhaps you had a Spotlight on the (hub) gears - Hub gear breakdowns or Spotlight on the rear sprocket - Jammed sprocket.

Adjusting Sturmey Archer hub gears

• For single cable 5 speeds: gear down into 2nd speed, do not park or fold, get down on your knees, adjust the indicator rod until the red ring just pops out of the axle.
  • Andy Follis, Apr 1999:
    You don't need to get down on your knees. You can balance a Brompton on its nose so that the rear wheel is comfortably up at chest height while you check the gear alignment. You may look silly (and your bike sillier still) but it keeps your trousers clean.
    Turn the handlebars to 90 degrees, tip the bike forwards (over the front wheel) until it rests on the side of the front wheel and one handlebar end.
    Maybe this only works with a T-type because you are resting the corner of the rack against your chest and the weight of the rack holds the rear triangle in the unfolded position.
• Malcolm Lyon:
  On the old style hub (S5/2) - you adjust the right hand rod so that the shoulder on the rod is in line with the axle end in middle (direct drive) position - this is in effect the overall 3rd gear postion. The left side indicator rod engages and additional gear train which gives an overdrive effect to give you a super low and super high (1st and 5th) gears. This side is easy to adjust - it is either in or out.
• Ken Twydell:
  One other thing to check is that the indicator rod does not pull right out to the end of the wheel nut when in first gear. - or to put it another way, it doesn't run out of chain. The Sprinter 5 speed uses a fairly long pull of the control and this must be catered for. The end of the axle should be only just visible in the 'window' in the wheel nut. This can be achieved by placing a suitable spacing washer between the wheel nut and the anti-rotation washer.
  I hope that this makes sense - the concept that I'm trying to explain is very simple but my words seem clumsy tonight.
  Another critical part on Sprinter Five speeds is the cable. I replaced mine with a high quality outer that had parallel strands rather than a helix. This was not on a Brompton but a Moulton APB.
• Custfold:
  The chain thingy is called the indicator, because it has a lining up (red line of Sprinter, flat = end of axle 3/5spd) in mid gear or other (Sprinter). The Sachs system is miles simpler with adjustment in top gear - take out the slack, and clip cable on, for SA adjust in mid position, and grip indicator against turning of adjustment nut/lock nut.
  Fitting a Sachs chain (better quality) to SA threaded adjuster can make improvement. Alternatively switch to 1 speed rear hub and front changer for 2-3 speeds (you'll need at least 54 t for normal riding, and 60+ for top gear)
• Susan Mathis, Mar 1999:
  When you adjust the cable correctly so the gears are in perfect working order, make sure you tighten the locknut really securly. I learned from working in a bike shop to use two plyers and tighten the threaded lockut firmly using the plyers for an even better grip. It sounds like your gears get out of adjustment so quickly because things are not tightened firmly enough. I've always thought of the Sturmy Archer three speed as the workhorse of hubs. Well cared for they should last practically a lifetime.
  • David Edge, Mar 1999:
    Indeed, but put the pliers on the long threaded part well aback from the joim, i.e. don't crimp the threads like I did!
• Custfold, Jun 1999:
  The long thin indicator rod with the red paint in the groove is used on the single cable SA 5 speed hub (Sprinter)
  The old SA (AW unless you have a really old one) 3 speed and the SA5 and other 2 cable 5 speeds use the flat face of the indicator rod formed where the top is milled away to fit the chain link to the rod. When in second/direct drive (3 speed) and direct/third (5 speed) this flat face can be viewed through the nut with the hole in as it lines up flush with the end of the axle to indicate that the unit is in direct drive (2nd/3rd gear).
  Alf Scroat however uses a far simpler technique wiv yor old traditional (they don't make'em like that any more missus (AS)) trigger control for 3 or 4 speed (if you really have an old one). For a 3 speed move the trigger mid-way between 2nd & 3rd and adjust the cable to get 'neutral' or no drive position when attempting to pedal. At this setting the indexing (indexed gears since 1930's with SA - stuff your Shimano puff (AS)) of the gears should come out just right.

The funny roller thing

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.

• Ken Twydell, Oct 1997:
  My Moulton APB3 had a Sprinter 5 speed fitted by its previous owner. It dosn't have the roller thingy but the standard right hand Sturmey nut as seen on three speeds since the begining of time. It seems to work well and is obviously more robust. I do keep the toggle chain greased and ensure that the indicator rod is screwed fully home and then unscrewed a touch to align with the cable run. One problem I did find was that it ran out of toggle chain when in first (ie the indicator rod reached the end of the nut). This was cured by having a spacing washer under the nut.
  [...]
  There is about 1mm of the end of the axle visible through the 'window' in the axle nut so adjustment is possible. When in 1st, there is half a link or so of the toggle chain still in the exteded portion of the nut. An extra pull on the cable gives a futher 1mm of free movement which is the limit of what can be pulled out of the hub anyway. My (early) hub has no red line, as such, but a raised collar that should be adjusted so that its centre is level with the end of the axle when in second. I have painted the collar red in order to ease adjustment.
  This setup works very well except.... sometimes when I have changed into 2nd from 1st, all is well until I 'honk' up a hill, when there can be a single slip of the gear. Tightening the cable adjustment makes this occurence more likely. This leads me to think that the problem could be the gear selector key or its slot in a sun pinion being rounded off slightly rather than the low gear pawls slipping. (I should add that the previous owner was unable to get the gears to work satisfactorily due mainly to a grosely over tightened cable - I suspect that the bike was often ridden with slipping gears) The problem does not seem to occur as often (if at all) when I have changed from 3rd to 2nd which leads me to suspect that the cable is also not running as free as might be - hence my interest in the roller. In use, I now tend to over shift from 1st to 3rd and back up to second. This seems to stop the problem but I also tend to avoid 'honking' in 2nd so it is less likely to occur anyway.
  I must get around to a full disassembly in order to check my theory re the gear selector key / sun pinion. Meanwhile the cable adjustment is very critical - but I can get by.
  I have the HSA488 Gear selector guide (roller) and the HSA 128 Axle nut. All I need is the HMW150 lockwasher and the HSA480 Gear selector guide support washer.

Hub gear breakdowns

• Custfold:
  I've been riding 1-speed Bromptons for almost as long as having ones with working gears. The current Sprinter went grind crunch about 6 months back, and when I took out the body, the high/low gears fell out in pieces. I knew the remaining life was limited, and the stresses set up in a hollow axle with a long slot in it are formidable with my riding (Transporting (more) luggage with a Brompton - Dave Holladay). So I visited my friendly wheelbuilder, and took away a 28 hole hub with sealed bearings, split down a SunTour 5 cluster (relatively thin for a freehub), and screwed the 14 (or it may be 13), hard on to the shoulder - et voila, a 3x 28h single speed hub. which is a delight to ride, apart from the fact that the biggest ring I could get in town was a 54. I think I can get a 60 from Middleburn ex stock, but suspect that a 64-66 would be ideal, to have as high/low on a front changer. Shimano/Sakae crank (130 pcd?). It is wonderfully light and whizzes along if only I could pedal fast enough.
  SA's can occasionally be 'sticky' especially it seems on the Brompton as the pedals often drag round when they could be freewheeling. In excess this force would appear to be low enough to resist by holding the pedals back, but sufficient to force the drive against the sprocket, and in the manner of a fuse (with a relatively small sprocket for the hub - compared to manufcturer's normal fitting for 26" wheels) the sprocket breaks.
• ____HPVert Alert____, Aug 1998:
  The Star 5 hubs [older SA5 model] were introduced in 1991, and I had the misfortune of getting one in my Brompton in 1992. In 1994, after 2 years of light use, and less than 1000 km ridden, the hub developed annoying random, but cyclic[sic] "clicks". I could not find a qualified SA mechanic locally (Stockholm, Sweden), so in the end I had it opened up and examined by a Sachs technician. He could not find the cause of it either but remarked that the pinion cogs looked well worn out. Anyway, I'll spare you the gory details, but the gist of it is that I had to decomission the bike, and, unwilling to throw good money after bad, am sitting here with --to me-- worthless [GBP] 500+ Brompton frame.
  Rumor has it that, because of the notoriously malfunctioning Stars, he Sturmey Archer has been known to replace them free of charge with the newer Elite 5's (which are an entirely new construction, ergo should be better). But of course this doesn't apply to those in faraway countries on the continent, because my faxes to SA about it weren't even replied to. And the Brompton apparently washes its hands as well. Not their problem.
  Lest you'll think that I am making this all up, let me quote verbatim from the book "Sturmey-Archer, The First Ninety Years" by P.M. Read (emphasis mine):

  TYPE '5-STAR' 5-SPEED WIDE RATIO (MK.1) (1991)
  RATIOS = -33.33% / -21.1% / D / +26.6% / +50%

  This is the new ( N.I.G. ) 5-speed which is of a totally new design concept, (even though the ratios are exactly the same as the previous S5/2 system) and the only part of this hub internal which partially resembles original S.A. hub gears is the gear ring. This design incorporates a new type of semi-planet cage/ platform with the low gear pawls operating from a 'Spring-ring' system on the lower edge, which is not unlike the internal pawl and ratchet system of Shimano hubs. The planet pinions are cantilevered out from the centre and held in place by new pattern pinion pins which have a grove cut in the lower end so as to engage on the pawel spring ring which protrudes through the pinion pin holes in the cage/ platform. There are other improvements such as a new type of clutch as well as a new type of driver with it's[sic] own set of pawls and anti-lock-up device but in spite of all these improvements, this hub gear is already suffering from 'teething problems' and complaints are already coming in from customers concerning rough running as well as main axles breaking across the key-way. These faults could be caused through the tolerances of the components being too close or the hardening of the components being at fault but whatever the problems are, something will have to be done soon before a repeat of the 'S.W.' disaster of 1955 rears it's[sic] ugly head again and does more damage to Sturmey-Archer's reputation.

  This is what I mean by dreck. The Elite 5 had better be good.
• Custfold, Mar 2000:
  The 3 speed AW has essentially been in use almost unchanged since the early 1930's with many pre-1939 3-speeds stil chugging along (please can I get a fixed one someone! as these are no longer made).
  The current AW model is the survivor of a much larger range which included close ratio and fixed gear.
  The simplicity is that through a slot in the axle a dog clutch locks elements of an epicyclic gear unit. On the 5 speed an additional bit of slot has another dog clutch, which switches basic hi-lo gear - which on the 2 cable SA hubs was operated from the Left side. In their wisdom designers found that by making a split part in the dog clutch which reacted to its position against the 3 speed stops, the 2 speed change could operate on the overtravel of the indicator rod as the gear cable was pulled.
  All sensible equipmant works on the KISS principle - hence reliable Dutch roadster bikes have 1 gear and coaster brakes - no cables to snap - no brakes to wear out rims etc.
  Weighing 95 Kg and generally finding the standard Brompton rather low geared (i use a 56 tooth ring on 1 bike, and a 61 tooth on another) I also discovered very early on that the bigger slot in the 5 speed axle and tiny bits of the gear change did not last at all - axles snap, toggles fall apart etc. So for a good basic reliable bike get the 3 speed, and if possible get the old metal trigger - the new one is rubbish, and does not easily allow the old trick of setting up the gears by holding the trigger mid-way between 2 & 3 and locating the null spot.

Failure design

• Custfold, Sep 1997:
  In terms of safety the failure of a gear indicator chain, or cable, will cause the gear to immediately change. This would be mildly embarrasing at low speed if the gear suddenly becomes high (you suddenly find it very hard work, and stop). Now imagine instead the failure of a gear change when really pushing it at 20+mph in top gear and then shooting into bottom gear. On a cumbersome this can often result in rapid engagement with the crossbar (one reason why cable guides on the top are rather a silly modern idea, old frames had cables along the bottom edges of the top tube)
  It is a pain but one get you home trick is to use a spare spoke (which of course you carry inside the rear frame) and this will screw in to the hub. This is than pulled out and bent over in whatever gear you want. Another is to note that in bottom gear the indicator is actually about 1/8" proud of the end of the axle (the flat on the indicator shouls align with the end of the axle in mid-gear - that's why its called an indicator!). With a bit of care the indicator can be pulled out, possibly unscrewed a bit, and bent to jam in the axle in bottom gear. The 5 speed Sprinter has considerably more stiff bit to pull out and bend over - as it has a red line to set up the gears with.
• Jane Thomas, Sep 1997:
  My Moulton APB S7 has the new Sturmey Archer 7-speed hub gear, and it is designed to fail in first if the cable breaks.
  According to Tony Hadland's excellent book, Sturmey did make a hub in 1905-1908 that also failed in bottom gear. I don't know why they changed the design to fail in top. Also the BSA 3-speed hub failed in bottom gear.
• Custfold, Sep 1997:
  This it may do but I do wonder on the effect of a cable/chain failure when one is belting along in top gear - the Shimano Nexus incidentally does the same bottom gear = slack cable. A penny pinching idea is to use a friction lever, with all stops cut off, which I have used until I got the rapid-fire changer, but have yet to fit - getting rather used to fishing for gears, and the rapid change possible with the friction lever.
• R.E.Burton, Sep 1997:
  My original query was prompted by my experience with the hub gear on the Brommo. The incidents, and I wonder how common they are, consisted of a failure of the key *inside* the hub into which the toggle chain screws whereby the thread becomes worn so that the toggle chain slips out. The internal must be dismantled in order to replace the key. This has happened to me about four or five times over the years. I don't complain about cable wear and tear - that is only to be expected.

Hub internals explained

• Roland Elsenberg, Jul 1999:
  Surely You have a Sprinter 5 with one cable and one gear changer instead of the 5 StAr on older Bromptons with two 3-Speed gear changers.
  My B's Sprinter has this inconvenience too. Shifting from 2nd to 1st gear is, like shifting from 4th to 5th, done by locking the big inner gear on to the hub's axle instead of the small one used for 2nd and 4th.
  This locking is done by a small sliding key protruding from the axis fitting grooves in the two inner gears, the suns of the two involved planetary gears. Due to the different transmission ratios the two suns rotate in respect to each other. So it is likely that the key, coming from 2nd (small sun) tries to get into the big sun (1st) just between two grooves of 1st gear. Tightening the cable will then press it against a solid part of the gear. Therefore it is unable to move further. Only moving the pedals will turn the gear so that the key finds the groove and slides into it. Then the gear changer will not pop out of of 1st gear.
  Shifting from 4th to 5th is similar, but this is done by loosening the cable. A spring will move the key the next time a groove passes.
  Cure: Try to pedal idly while shifting into 1st.
• Ken Twydell, Jul 1999:
  To get into 1st gear you are selecting a different sun pinion to be meshed with the axle by sliding across a raised 'thingamy' located in a slot in the axle (in the Sprinter hub). As the two sun pinions rotate at dfferent rates, the chances of the slots in both suns being perfectly aligned when at rest are remote. Therefore, it is recommended that you are moving and pedaling gently when selecting 1st - as seems to be born out by your findings.
  
  When in first gear (ie actually engaged rather than merely selected at the changer), I find that the cable should not be too tight. A pull on the exposed cable should still allow a minute amount of movement at the toggle chain.
  When in 5th (again actually engaged!), the cable should be quite slack. The large amount of movement between 5th and 4th gear on the lever should take up all of the slack and still provide a fair degree of movement at the toggle chain.

7 or more speed hub gears

• Leonard Rubin, Oct 1997:
  The problem with the many new 7-speed (and higher) hubs is that they are all 135mm or so in width, and the Brompton's rear triangle measures 110mm. While it is possible to "cold set" (force bend to a new width) a steel frame a few millimeters to accomodate a different width hub, in this case the difference is far too great.
  For this reason, I have designed and built some prototype replacement rear triangles, in both steel and titanium to accomodate wider hubs, and, when combined with my weight-reduction diet (lots of tasty components and custom bits that I sell) the results are quite astounding!
• Leonard Rubin:
  This is not the only barrier to their use by any means, as limited spoke hole drillings, excessive weight, limited range, high frictional losses, noise, interference with the Brompton chain tensioner (clever derailleur-like thingy), cable-routing and shifter clearance challenges make them somewhat unattractive. I have heard rumors of an upcoming very light, high-performance 14-speed hub from Rohloff, and a design project along those lines from Spinergy, but in the 20 years I have been active in the bicycle business, I have become, lets say, a tad skeptical regarding the likelihood of true "high-performance" internally-geared hubs (read narrow, lightweight, efficient, wide-range, etc.) appearing in the marketplace, due mostly to reluctance on the part of investors, manufacturers, distributors and retailers to operate outside of conservative financial assumptions.
• Custfold, Oct 1997:
  Alternatively fit a Sachs 12-speed/Shimano 7 in a widened & strengthened rear frame, I've done the latter, but the brake has to come off to make it fit, and it weighs a lot more.
• Custfold, Nov 1998:
  I have done the conversion [to 7 speed hub] - it may be that we can offer this in the very near future as the 'prototype has now covered many miles at moderately high speed and loads
  One caveat though the spokes are well under 4.5" long and thus at seriously bad nipple entry angle and severe bend over the outside of the flanges - the bike also gains about 1.5lb IIRC. The wheel took 3 months to get finished but we got the basics worked out and swore a lot.
  The rear triangle is rebuilt but using essentially the same unit - new drop- outs shorter w/base (about 8mm) and for me extra bracing at weak pivot point - and the chain tensioner has to be changed as it don't work with the nexus unit.
  I'm working with a frame builder and also deal with the sub contractor who built many Aerobikes frames, and makes some of our accessories, so we may have something interesting soon.
  I would stress that
  1. the spokes are very short and hard to lace up
  2. the hub and extra spokes do weigh more (a fair lump more!)
  Still the 104" top gear is much more comfortable when I open up to speed in town
• Custfold, Mar 1999:
  I have been riding a Nexus 7 less brake with modified chain tensioner for over 1 year now - you saw it at Coach & Bus '97 IIRC - it was at Ventnor and appeared on FAQ pictures (bike was white - now red-ish with black & purple bits IIRC), and many Brompton users have seen (and some ridden) the bike - it has Cantilever brakes etc and we may be making some more conversion frames very soon - as the long term testing seems to be proving the unit - apart from a difficulty in getting spokes and reducing spoke breakage tendencies (although this is with me riding it) - could Mr Parry have had the tape measure out at Ventnor perhaps?
  The Nexus gear range is great and the hub is smooth (for me). Other pluses are that one does not need to remove the gear cable when working on tyres with the wheel out.
• VELODROOM -- urban mobility concepts, Mar 1999:
  [...] the gear ratios of the new SRAM Spectro (the hubgears formerly known as Sachs). So here they are:

  Gear#	Spectro T3	Spectro P5	Spectro S7	Spectro E12
  1	1:0,73	1:0,63	1:0,574	1:0,697
  2	1:1	1:0,78	1:0,677	1:0,851
  3	1:1,36	1:1	1:0,809	1:1
  4		1:1,28	1:1	1:1,179
  5		1:1,58	1:1,236	1:1,333
  6			1:1,476	1:1,481
  7			1:1,742	1:1,612
  8				1:1,766
  9				1:1,916
  10				1:2,061
  11				1:2,217
  12				1:2,364
  	186%	251%	303%	339%

  If you have any further questions (flange diameter, width, etc.) just ask(Where can I find out more? - Belgium), I got the technical documentation from SRAM.
• ____HPVert Alert____, Jun 1999:
  [For those for whom the Rohloff is something new, see http://www.rohloff.de/english/products/speedhub/index.htm]
  I was under a _clear_ impression, that the Rohloff Speed 14 hub was not _recommended_ for smaller wheels than 20". Something to do with the torque...
  http://www.rohloff.de/english/products/speedhub/kompatibilitaet/kompatibilitaet.htm
  just as elsewhere in the docs they clearly state the smallest PERMITTED sprocket/ largest chainwheel combinations etc. I have not followed it up closely but remember that even installing it in a 20" wheel required a specific (developed for Rohloff) Alesa rim or else the loads on the hub itself would become too great.
• Deborah Eacock, Feb 2000:
  An SA representative told me last year that they were working on a narrow model (probably without the brake) specifically to fit the Brompton. It seems that progress is slow at the SA works. A2B reviewed the SA7 in August 97, and compared it favorably against the Nexus and Sachs versions in December 1997.

Hub gear efficiency

• Phil Gough, Mar 1998:
  The usual wisdom when this topic is raised is that at the extreme ratios, lowest and highest, the efficiency losses are about 5 per cent, and on direct drive equivalent to a derailleur. But bear in mind that most derailleurs that one sees around are not well maintained or adjusted and are generelly filth-lade so in practice these must be loosing at least 2 per cent IMO. The Brompton chain tensioner must also impose its share of spring load and friction.
• David Henshaw, Oct 98:
  The 5-speed Sturmey is less efficient than the 3-speed in gears 1 and 5. Try riding up the same hill on a 3-speed in gear 1 and a 5-speed in gear 1. The lower gearing on the 5 gives no real advantage. I was sceptical until Andrew Ritchie, the man himself, demonstrated this. Now I believe it. And the 5 is very adjustment-sensitive, unlike the 3, which lasts forever and ever.
  On a 5-speed, I'd go for a 14-tooth sprocket, which gives about 8% lower gearing. But, please remember to change the shim pack - the 14T is thicker than the 13T... The 12% optional lower gearing is certainly worth fitting on the 5-speed if you want really low gearing, but I'm not sure about the 18% - a front changer is probably a more sensible option.
  I'm still happiest with a light, efficient 3-speed with standard gearing. My clunky old bike still holds the unofficial Brompton speed record, set at CycleFest 1996 by Richard Grigsby.
• a2bmagazine, Oct 98:
  Just to add fuel to the fire - the 5-speed seems to vary in efficiency, but I can't say I've ever noticed this effect with the 3. Many years ago, Sturmey used needle roller bearings in the pinions, but decided the cost wasn't worthwhile. Maybe they should go back to rollers on the 5 and 7-speed...
• Andrew Henry, Oct 1998:
  Chris Juden wrote an article on this sort of thing on the hardcore-bicycle-science list at cycling.org. The full article is at http://cycling.org/lists/hardcore-bicycle-science/hardcore-bicycle-science-archive-hyper/hardcore-bicycle-science.199704/0128.html
  [...]
  Hans-Joachim Zierke posted the following numbers to rec.bicycles.tech

  Sachs claims the following figures, in comparison to 98% efficiency of a "normal" drivetrain in new condition:

  1 -	93%
  2 -	93%
  3 -	96%
  4 -	97.5%
  5 -	95%
  6 -	93%
  7 -	92%

  They do not publish input power for measurement.

• Carsten Thies, Dec 2002:
  The article [that Carsten Thies summarized] from Radmarkt 12/1993 was republished in Pro Velo No. 5 pp. 16-20. under the title "Der Wikungsgrad im Fahrradantrieb". Although this issue is no longer available, photocopies are available for a small fee by editor Burkhard Fleischer (used to be DM 0,50 per page plus DM 4,- packaging and postage; EUR 1,- = DM 1,95583) at:

  PRO VELO Riethweg 3 D-29227 Celle fon +49 +5141 86110 fax +49 +5141 84783 Fahrradmagazin.ProVelo@t-online.de

• Willi Mindak, Nov 98:
  I received an e- mail today from Marketing at SA. This was in reply to an e- mail I send over a month ago. It says:
  

  Dear Sir
  The only information I have on this type relates to the 5 speed hub, the information is as follows:-
  Efficiency
  

  Gear	Ratios	Efficiency
  Super Low	0.667	89%
  Low	0.789	93%
  Normal	1.00	96%
  High	1.266	94%
  Super High	1.5	88%
  Efficiency Test Conditions
  Motor Torque Arm balance weight = 2.2Kg
  Motor Speed = 64 RPM
  No. of chainwheel teeth = 46
  No. of Sprocket teeth = 18

  
  I hope this information assists you.
  Yours faithfully
  Trevor Wilkinson
  Marketing Executive

  
  No surprises here. Legend had it that 1st and 5th gear were a bit harder to work. Third gear is best with no internal ratio; I take it the 4% are just bearing/ chain losses. I also asked for the 3 speed values, but no joy. Anyway, these values are in the expected range. They are actually better than I thought.
• Mike Hessey, Mar 2000:
  I have found the original 2-cable 5-speed of my Brompton T5 reliable - I only bought a single cable 5-speed recently (on a Micro, rather than a Brompton). On the older one, using the lowest gear feels like pedalling through treacle - ie inefficient, and only used in emergencies. The newer one feels much better in this respect.
• Carsten Thies, Jan 2003:
  In the 1998 catalogue, Sachs gave the efficiency of its three-speed hub as 94% in low gear, 97% in direct gear and 93% in high gear. This corresponds to the numbers for 200W input in the Radmarkt / Pro Velo article. At 100W, the efficiency is hardly 93%-96%-91%. AFAIK SRAM has not changed the internals of the three-speed hub (only 5- and 7-speed), so these numbers should apply to the present Bromptons, too.

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

• Stein Somers, Oct 1998:
  My guess: in the extremer gears, the planets in the cage roll on a bigger central fixed cog, hence they are smaller in diameter and make more rounds per minute. Both factors increase the friction at their (simple) bearings. Maybe on top more than three planets are needed to cope with the driving forces because the teeth on a smaller planet make less firm contact with the central cog.
  Come to think of it, the basic planetary system can only reach a 2:1 drive ratio using infinitely small planets. That's a 400% gear ratio, low to high gear. (SA-3 has 178%, SA-5 has 225%). So how does the illustrious Rohloff hub obtain more than 500%??
  • Carsten Thies, Jan 2003:
    It has two identical planetary gears in line, giving 7 gears^*, plus an additional step-down planetary gear for the lower 7 gears.
    * it's not 3x3=9 gears because step-up step-down or vice versa would give the same as direct gear.
• Custfold, Oct 1998:
  The reason for the extreme high/extreme low being accessed by pulling the second lever should give a clue - the old SA5 system used a second cable to pull the dog over on the LHS of the unit and engage a step-up ratio in the drive chain - otherwise the middle 3 were direct into the gear cage. This in turn means a bigger slot in the axle and extra little piece to slide in it for all 5 speed hubs. The Sprinter merely uses a longer pull stroke to operate a 2-stage little bit in a slot from 1 cable.

Lubrification

• Rob Cope, Oct 1998:
  Little mention has been made of lubrication. Sticky Sturmeys frequently free up if Sturmey oil is *carefully* injected into the hub. I do not like the 'greased for life' position now adopted by the makers - an excuse not to put proper oil seals in? Certainly 'grease' Sturmeys once oil injected tend to forget their housetraining for roughly a fortnight (and of course, once you switch to oil you have to keep to it). One reason I stick to an ancient twin-chain S5 is that it has a proper oil hole. Actually, its quite therapeutic dripping oil into it every month or so and I'm off to do so now. Amateur psychologists need not comment.
• Jane Thomas, Jun 2000:
  If you are taking the gearbox apart, it might be worthwhile getting the correct greases to put it back together with - I think the grease for the bearings isn't as important as the grease that goes inside, which is a very soft, non-sticky version.
• jamcl3, Jun 2000:
  I used white lithium grease from the hardware store for the internals, and sticky automobile wheel bearing grease for the bearings.
• Custfold, Jul 2000:
  According to SA 's Mr Wilkinson the grease (very thin & tenacious) is the same spec as that used by Mercedes Benz on some geared device.
• David Edge, Oct 1998:
  I had to withdraw my 5-speed for overhaul when one chutch stopped ratchetting. I think this was because some of the very sticky bearing grease I had slapped in had migrated to the ratchet. Maybe grease migration affects 5-speeds as they get older.
• Mike, Jul 2000:
  I have dribbled oil down the gear selection chain hole !
  • Peter Amey, Jul 2000:
    I think there are two possible problems with this:
    1) Once you start using oil you must keep using it (and regularly) because it washes the grease off. I understand that regular oiling is probably the best treatement for hubs (they used to have oiling points built in).
    2) If you lay the bike on its side the oil dribbles out again!
  • Mike, Jul 2000:
    
    1) I didn't put that much in ;) I hope it'll keep the grease "moist" Oil usually coats ("soaks in" to the microscopic pits) metal objects. Some oils do "wash" - the detergent oils as used in engines where recirculation pumps are used to maintain lubrication. The 3-in-1 (Esso Handy Oil) type things should be better.
    2) Does that not depend how soon after dribbling it in ? Anyway, lay it on the other side !
  • John Collier, Apr 2003:
    You should never use 3-in-1 oil in a SA hub!! The viscosity is too low and it has a very high acid content. It also becomes hydoscopic when exposed to the (localized) high temperatures in the SA hub. This will lead to corroded internals.

1 speed

5 speed versions

• Joel Parks, Nov 1999:
  In fact, there were at least two versions of the 5-spd SA with cables running to both sides of the axle. One used an indicator chain on both sides, the other used an indicator chain on the drive side and a bell crank driving a pushrod on the non-drive side. I (ab)used the former for several years while a student in Boston, only to retire it when I found the hub shell had developed 3 cracks in the axial direction from the drive side almost to the non-drive side. I was in the habit of flying off curbs at full speed, not to mention the bad roads and trolley tracks. I broke a couple of axles too.
• Roland Elsenberg, Nov 1999:
  I too have a Sturmey with two shifters, the kind Joel described with the two indicator chains. The hub contains two planetary gears which share the outer ring and the cage containing the planets. The right cable works like that of a 3-speed. The left one pulls a key through a slot in the axle and locks the small or the large sun-wheel onto the axle. Although the left shifter is borrowed from the 3-speed only two positions are used. This gives 2 * 3 = 6 possible combinations. When the small sun wheel is locked the right shifter works like that of a conventional 3-speed but with a faster 1st and a slower 3rd. Locking the big sun wheel also gives a 3-speed, but with a slower 1st and a faster 3rd. Like with the 3-speed, the middle gear has a 1:1 ratio. Thus both middle gears, small or big sun locked, have a 1:1 ratio. Therefore 6 positions give only 5 gears. Shifting through all 5 gears goes like this:
  • Start in 1st, left cable loose (2nd), right in 1st position
  • then 2nd gear: tighten the left cable (1st), right stays in 1st
  • 3rd gear: right shifter in 2nd position, left stays in 1st
  • 4th gear: right shifter in 3rd position, left stays in 1st
  • 5th gear: loosen left cable (2nd), right stays in 3rd position
  It is easier done than explained.
  To me shifting seems to be faster than with the sprinter. As the key is moved only from 1st to 2nd and from 4th to 5th most of the work is done with the right shifter. Like with a 3-speed it is possible to abuse the hub by shifting upward without taking force of the pedals. Since 5 months I have only ridden the Sprinter type because I favour the Schwalbes on the new bike, but this discussion reminds me of the merits of the 5 Star (two cable type). Perhaps I try tomorrow. Only disadvantages are: The axles left end sticks out about 1" and some people get confused by two shifters. Otherwise I would prefer it.
  It certainly is more tolerant [of misadjustment], since the indicator rod travels like that of a 3-speed roughly the same way for 3 positions where the Sprinters rod has 5 positions. The relative effect of misalignment must be smaller. On the other hand only the Sprinter has the trolley. When the cable of my Sprinter has lenghtened a bit the hub tends to stick in 4th gear when I put the shifter to 3rd. To give the same effect, the old 5StAr must be severely misaligned. The difference is minor to the difference compared to Sachs (now SRAM) hubs. All Sturmeys shift way faster than all Sachs I have ridden so far.

The Brompton Folding Bicycle FAQ - please comment