# Brompton gear systems



## Yellow Fang (27 Nov 2011)

I have been having problems with Brompton ever since I decided to replace the sprocket earlier this year. The hub came apart and it took me hours and hours of work trying to get it to function properly again. Even now it's not right. I get it working for a while, then it starts misbehaving again. I am thinking that next year I might get a whole new rear wheel but with two speed derailleur gears rather than hub gears. I think I can get away with two gears provided they're the right ones. I am also considering asking SJS cycles to build me a wheel based on the Sturmey Archer kick shift hub, but I wonder whether this hub is compatible with a Brompton. Would the back wheel lock up as you tried to fold up the bike?


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## GrumpyGregry (27 Nov 2011)

Couple of guys in the states are using the S2 I think, and I'm sure I read one report of an S2C (with the coaster brake). As it happens I run an S2C on a 700c wheeled bike. They commented you just need to be 'careful' when folding. But is the S2/S2C available in a width that will fit the Brompton rear triangle and if so, will the chainline be the same? Also the size of the sprocket may require a modified tensioner depending on how big you go.


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## Night Train (27 Nov 2011)

What' wrong with the hub gear? Maybe it can be fixed to make the ride better in the meantime.


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## Yellow Fang (27 Nov 2011)

It doesn't seem to let me select all three gears, no matter how much I push the little rod in or out. The chain was going a bit slack while coasting - definite sign something is wrong in the hub.


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## Twanger (28 Nov 2011)

If you've adjusted the indicator rod as per the instructions (1 mm sticking out when you look through the view hole in middle gear - there's a very clear picture in the user manual), and it doesn't work, then there is, as you said, something wrong with the hub. Changing the sprocket shouldn't affect the hub (I have done so on mine, an SRAM, and have had no probs). If the hub "came apart", I'd take it in for servicing. I wouldn't know how to begin servicing an epicyclic gear myself.

Is the lock nut locked, or is the gear cable slipping somewhere or need tightening?

Oh, and are you sure you have the right indicator rod? SA and SRAM use different rods.


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## SavageHoutkop (28 Nov 2011)

I have much more grief with my derailleur than with my hub, but again it's probably just that I don't care for it enough.
My derailleur doesn't like wet weather much, and I've also just noticed my cable has broken by the hinge (which is probably why it's not changing at the moment).In winter I pretty much ride 3 speed rather than 6. I also am not sure how the derailleur, even if it is working perfectly, would handle riding in snow (as I tend only to have 3 working gears in winter, I've not tried this!).

My hub is now working like a dream. I've never opened it up personally but I have had the bike shop open it up for me when there was noticable chain slack while freewheeling, it's been behaving ever since. Mr SHK's also had the chain slackening off problem but his also rides OK now (I think his hub is busted, personally - it feels rough, but it rides OK and selects all 3 gears). His has always been a harder ride than mine, which is odd as they were bought from the same shop less than a month apart. Neither of us have had gear selection problems though (aside from riding without the gear indicator rod correctly adjusted, of course) - TBH I haven't adjusted my rod in months and months.


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## Yellow Fang (28 Nov 2011)

Twanger said:


> If you've adjusted the indicator rod as per the instructions (1 mm sticking out when you look through the view hole in middle gear - there's a very clear picture in the user manual), and it doesn't work, then there is, as you said, something wrong with the hub. Changing the sprocket shouldn't affect the hub (I have done so on mine, an SRAM, and have had no probs). If the hub "came apart", I'd take it in for servicing. I wouldn't know how to begin servicing an epicyclic gear myself.
> 
> Is the lock nut locked, or is the gear cable slipping somewhere or need tightening?
> 
> Oh, and are you sure you have the right indicator rod? SA and SRAM use different rods.


 
I've never noticed a view hole - where's that? The lock nut was finger tight, as far as I remember. I've discovered it's not a good idea to overtighten it though. The indicator rod is the same as it's always been.


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## Yellow Fang (28 Nov 2011)

SavageHoutkop said:


> I have much more grief with my derailleur than with my hub, but again it's probably just that I don't care for it enough.
> My derailleur doesn't like wet weather much, and I've also just noticed my cable has broken by the hinge (which is probably why it's not changing at the moment).In winter I pretty much ride 3 speed rather than 6. I also am not sure how the derailleur, even if it is working perfectly, would handle riding in snow (as I tend only to have 3 working gears in winter, I've not tried this!).
> 
> My hub is now working like a dream. I've never opened it up personally but I have had the bike shop open it up for me when there was noticable chain slack while freewheeling, it's been behaving ever since. Mr SHK's also had the chain slackening off problem but his also rides OK now (I think his hub is busted, personally - it feels rough, but it rides OK and selects all 3 gears). His has always been a harder ride than mine, which is odd as they were bought from the same shop less than a month apart. Neither of us have had gear selection problems though (aside from riding without the gear indicator rod correctly adjusted, of course) - TBH I haven't adjusted my rod in months and months.


 
Sounds like I should stick with the hub gears then.


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## SavageHoutkop (28 Nov 2011)

Yellow Fang said:


> I've never noticed a view hole - where's that?


 
Er.. hang on. OK, read your post properly now. Which hub gear do you have - the BWR (i.e. 6 speed) or the Sturmey Archer close range 3 speed?

And while changing the sproket _the hub just came apart?!?_


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## Yellow Fang (28 Nov 2011)

SavageHoutkop said:


> Er.. hang on. OK, read your post properly now. Which hub gear do you have - the BWR (i.e. 6 speed) or the Sturmey Archer close range 3 speed?
> 
> And while changing the sproket _the hub just came apart?!?_


 
It was the Sachs 3 speed, which is part of SRAM now (I think). I think the bike was made between Sturmey Archer going bust and it being bought by SunTour.

The hub didn't fall apart. I undid various nuts and bolts trying to work out how to get the sprocket off.


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## GrumpyGregry (28 Nov 2011)

1625771 said:


> My understanding is that the hub dimensions are fine but the 36 spoke drilling is not because it makes getting a pump on the valve very tight.


90 degree adaptor perhaps....


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## SavageHoutkop (28 Nov 2011)

Yellow Fang said:


> It was the Sachs 3 speed, which is part of SRAM now (I think). I think the bike was made between Sturmey Archer going bust and it being bought by SunTour.
> 
> The hub didn't fall apart. I undid various nuts and bolts trying to work out how to get the sprocket off.


Ah.
Might be worth seeing if a LBS could fix it for you, else perhaps time to get a new hub? Might be worth upgrading to a 6 speed at the same time, if you're inclined. I've had 'brilliant' service from brilliantbikes; and they seem to have the rear (hubbed) wheels in stock; in both BWR and Sturmey flavours. What you can also do is upgrade to the 6 speed, and IIRC you can swap out the rear wheel for one without a hub, leaving you with a 2 speed.


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## Yellow Fang (28 Nov 2011)

I see Moulton do a kick-shift version of their bikes, i.e. the TSR2. They have small wheels. How many spokes do they have?


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## Yellow Fang (28 Nov 2011)

SavageHoutkop said:


> Ah.
> Might be worth seeing if a LBS could fix it for you, else perhaps time to get a new hub? Might be worth upgrading to a 6 speed at the same time, if you're inclined. I've had 'brilliant' service from brilliantbikes; and they seem to have the rear (hubbed) wheels in stock; in both BWR and Sturmey flavours. What you can also do is upgrade to the 6 speed, and IIRC you can swap out the rear wheel for one without a hub, leaving you with a 2 speed.


 
I'm not sure I need six gears. Most days I only use two: 1st gear for hills and 2nd gear for everything else. 3rd gear is too high geared even after having a larger sprocket put on the back.

Part the problem is I'm not sure I trust my local Brompton dealer to do a good job. I never rated their know-how before they started selling Bromptons. The local Evans appears to have stopped selling them. The shop I bought it from, who I did rate, closed down years ago. The nearest LBS I trust to do a good job is in Oxford.


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## GrumpyGregry (28 Nov 2011)

Couldn't you whip the wheel off and send it....


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## SavageHoutkop (29 Nov 2011)

Yellow Fang said:


> The nearest LBS I trust to do a good job is in Oxford.


 
Warlands? They were the ones that opened up my hub.


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## Yellow Fang (29 Nov 2011)

SavageHoutkop said:


> Warlands? They were the ones that opened up my hub.


 
That's the one.


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## Night Train (29 Nov 2011)

I have opened and repaired my Sachs 3 speed with no major issues. Mine wasn't shifting properly and slipping catching the wrong gears.

I found the little bar that the indicator chain screws into was cracked and then broke in half and the pawls for the freewheels inside were sticky.






I gave the hub a good clean and reassembled with a new part to replace the one that broke.

It now works fine.

To adjust the indicator chain you should have a black block of plastic on the end of the cable. It has a little metal trigger that catches the thread on the indicator chain.




Disconnect the indicator chain from the plastic block by pressing in the metal trigger.
Select 3rd gear on the shifter.
Insert the indicator chain into the plastic block, it should ratchet against the metal trigger. Stop when the slack in the indicator chain is almost all gone.
In third the chain should be just snug but not pulling and this should then work fine. If there is still a shift problem adjust the indicator chain, by only 1 or 2 threads in the plastic block, in either direction.

I have uploaded the Brompton manual. Gear adjustment is on pg15.


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## Yellow Fang (29 Nov 2011)

I had another go at it last night, but it's no better. It's not changing gear at all now. I suspect the sliding rod may be broken. I find one of the problems is that you just don't know how tight to screw everything up.


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## Yellow Fang (30 Nov 2011)

1625771 said:


> My understanding is that the hub dimensions are fine but the 36 spoke drilling is not because it makes getting a pump on the valve very tight.


 
There's a version of the S2 (without the coaster brake) which has 32 spoke drillings, but annoyingly it only comes in the larger size, There's a smaller size with an Over Locknut dimension of 110mm that looks like it might fit on a Brompton, but it seems like that version only comes with 36 spoke drillings.


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## Yellow Fang (2 Dec 2011)

I see the Sturmey Archer S-RF5(W) comes with a 148mm axle and a 111mm over lock nut width. It comes with 28 spoke drillings too.

I emailed Sturmey Archer's European office about the S2 duomatic spoke drillings issue. It worked with Schmidt and their SON XS dynohub for the Brompton.


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## Yellow Fang (5 Dec 2011)

It looks like the Sturmey Archer S-RF5 is a bit temperamental. So I'll drop that idea. Sturmey Archer say they have no plans to introduce a duomatic with 28 spoke holes, but just because the shell has 36 spoke holes doesn't mean you have to use them all, does it? Presumably you could still build a wheel with a 28 hole rim and a 36 hole hub.


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## Night Train (6 Dec 2011)

Yellow Fang said:


> Presumably you could still build a wheel with a 28 hole rim and a 36 hole hub.


You could but spoke measurment would be a bit hit and miss. It might mean some spokes needing to be filed down a little and others showing threads.


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## Yellow Fang (6 Dec 2011)

I'm going off the duomatic idea too. The gear ratios are 100% and 138%. I believe the gear ratios on my old hub were 75%, 100% and 133%. I rarely used 3rd gear (133%) because it was too high. I used 2nd gear most of time with 1st gear for hills. To fit a duomatic I'd either have to fit a much bigger sprocket or a smaller chainwheel, and both of these are quite new. This factor is putting me off the two-speed derailleur system too.

A couple of people from the Yahoo Brompton group have installed an S-RF5 hub in their rear wheel. I gather from other cycling forums that the S-RF5 is difficult to set up, tends to slip and requires lots of tweaking with the adjustment rod. I wonder if that's just the case for the narrower hub or for the wider hub too.

Edit: a potential way of getting around the gear adjustment problem is to install a barrel adjuster on the gear shifter.


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## Crankarm (25 Dec 2011)

Forgive me for being blunt but it looks like you should take your wheel and hub to some one who knows what they are doing .................... Talking about getting alternative hubs, gear systems might be a waste of money and time when the solution might be a lot simpler and cost effective by getting some one to look at your existing one and repairing/servicing it for you. Reading to Oxford is not so far.


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## Yellow Fang (25 Dec 2011)

Crankarm said:


> Forgive me for being blunt but it looks like you should take your wheel and hub to some one who knows what they are doing .................... Talking about getting alternative hubs, gear systems might be a waste of money and time when the solution might be a lot simpler and cost effective by getting some one to look at your existing one and repairing/servicing it for you. Reading to Oxford is not so far.


 
Could do, Warlands would do a good job. OTOH I could get a whole new back wheel from SJS cycles. I am not sure what rim life Brompton wheels have, but I've had the bike for about eight years now.


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## Yellow Fang (5 Jan 2012)

The new wheel arrived. The Sturmey Archer is physically much larger than the old Sachs hub. Annoyingly, it looks like I will have to send off for another part because the gear anchorage for a Sachs is different from a SA hub.

I notice the new wheel has a wear indicator groove in the rim. The tyre seems to go on much easier too. I recently switched over to Brompton Green tyres because they're easier to change than Schwalbe Marathons, but I bet even changing Marathons would not be so hard on these rims.


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## Roger Saunders (28 May 2012)

I had terrible trouble with my SRAM hub. Eventually took it apart sufficient to soak away oll the gunge in an oil bath then reassembled it with clean car oil as a lubicant. It is better than new now!

The problem was muck salt and grit which had got in during the bad weather.


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## Brommyboy (29 May 2012)

Spares for the Sram are not normally available but a new internal assembly is, and this is very easy to fit if your LBC does not understand hub gears. the Sram is a very effective unit: Heinz Stucke who has ridden around the world several times used them because he reckoned to get 50000km per unit despite carrying up to 70 kg load!


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## Roger Saunders (29 May 2012)

You can buy the wheel bearings too.


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## Rohloff_Brompton_Rider (29 May 2012)

if you don't want the wheel anymore i'll have for spares for my wife's older brompton.


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## Roger Saunders (29 May 2012)

If you get the wheel you could try my technique on it!


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