Sturmey-Archer 4-speed shifter mounting

[rogerzilla]

Probably for hubgearfreak, this one

The 1960s 4-speed and, to a lesser extent the 3-speed, shifters are designed to be mounted on a curved section of handlebar. If fitted to straight bars - I'm thinking of a Brompton S-type here - the shift lever will hit the bars before it gets into "1", because it is designed to come lower than the bottom of the shifter. Any suggestions to get round this? I can see that I *might* need to remove the existing clamp by drilling out a rivet and then bolt the shifter body to a Brompton clamp, which holds the shifter in front of the bar to avoid such problems. I don't want to use a Space Grip or similar because it would probably mess up the fold and the shifter would be too hard to reach.

I want to use an FW on the Brompton (as well as an AW and an AM...the 4-speed shifter will work any of them).

[Mark R]

I am not 100% but I think there are two different 4 speed shifters.

The type fitted to bikes like 1950's roadsters definitely won't work on straight bars; I have tried, and, like you say the lever hits the handlebar so you can't select first.

I think the type fitted to f-frame Moultons is different in having a shorter lever and may be more suitable.

[hubgearfreak]

never tried it. sorry i can't help

[rogerzilla]

I am not 100% but I think there are two different 4 speed shifters.

The type fitted to bikes like 1950's roadsters definitely won't work on straight bars; I have tried, and, like you say the lever hits the handlebar so you can't select first.

I think the type fitted to f-frame Moultons is different in having a shorter lever and may be more suitable.

That's useful, thanks. The shift lever is solid and unbendable, BTW, even if I wanted to risk a rare NOS component!

[GrahamNR17]

Only just spotted this thread. Here's the four general models that were for four-speed hubs:

GC2 (3 & 4 sp) 1948-53
GC4 (4 sp) 1938-48 (Long Lever)
GC4A (4 sp) 1953-70
GC4B (4sp) 1956-? (Above-Bar mounting)

None currently in my collection, but I'd wager the earlier models won't hit the bar as they were designed for under-bar mounting so logically would be on a straighter part perhaps?

Apologies that I can't offer more.

[random37]

Graham, in a couple of days you'll have two. But only one that works.

The later one fits on flat bars.

[Spiny]

My suggestion:
Ditch the Brompton S bars (which, IMHO, are too short anyway) and replace with a flat mountain-bike bar, e.g. the Easton EA30.
Cut these down to a sensible 54cm length using a pipe-cutter (2cm per-side for the Eastons).
Get some curved or angled 'bar-ends’ to fit that will also carry the Sturmey 4 speed trigger. With the longer bars there should be no interference with the Brompton fold given careful choice of suitable bar-end and positioning of the trigger. Have fun with cable routing!

[Spiny]

Simpler alternative:
Change the Brompton bars for some with a slight curve, (e.g. shallow-riser MTB bars or cut-down 'North Road' bars - see LIttlepixel's 'Mercton') and fit the Sturmey changer to the curvey bit! May be more of challenge to position the trigger not to foul the folding though...

[SA_SA_SA]

Why not the FM for the Brompton?

Why did SA base all the 5 speeds on the FW not the FM, whose ratios seem more suitable?

Is there a technical reason why five speeds with constant 27/25% jumps (sachs/sram) and all 33% jumps (newest sunrace SA 5 speed), have only recently become available?

[rogerzilla]

Because the FM has a habit of exploding through its shell It's not as foolproof as an AM (which transforms a Brompton).

I thought about riser bars, but my stubby bar ends would (a) look naff and (b) probably foul the front wheel when folded.

I think I'm going to have to drill out the rivets holding the shifter body to the clamp, tap one of the holes and bolt it to a P-clipto hold it slightly in front of the bars - which is where a Brompton plastic shifter sits.

[spanner]

the sa sw which was brought out to replace the aw which was a tried and tested reliable hub also had a problem with exploding it only lasted about three years before sa went back to the aw and withdrew the sw hubs from sale
i have a trent tourist and the previous owner told me he had the hub replaced several times due to the hub problem he used it when he was at school for doing his paper round and paid the bike up on the drip as he called it i have the payment book somewhere, the bike needs restored and will do so one day hopefully sooner than later.

[rogerzilla]

The SW suffered from rapid wear to the "silent" crescent-shaped pawls, which led to slipping or jamming. The FM had a weak LH ratchet which was able to break and then burst the alloy shell.

[SA_SA_SA]

A pity they didnt fix the FM: it seems have more logical rations (three close and superlow).
Another pity they didnt base the 5 speeds on it, and fix its flaws then.

[rogerzilla]

Yes, the FW has a similar range to the AW but with slightly closer ratios. Assuming you gear it up for direct drive as the most commonly-used gear, say 60", you gain a lower ratio at the low end compared to the AW (40" vs 45") but lose a lot at the top end (68" vs 80").

The progression is a little odd too: 40", 47", 60" and 68". Big jump between 2nd and direct drive.

[SA_SA_SA]

You could try fitting a minoura lamp bar to the drops, and fitting the trigger at the end near and near level of the brake hood:

almost STI, I have done some thing similar with a derailleur thumb shifter.

Was there ever a 3 speed with +-25% or +-27% steps?