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 (Which model is meant for me? - 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 Stories featuring Bromptons (all true) - 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?


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...