Brompton M3L gear problems

[LCpl Boiled Egg]

Hi,

My Brompton M3L is having some problems with the gears (Sturmey Archer hub). 1st gear is fine, but as soon as I change up there's noises from the rear wheel and the pedals slip now and again. It makes a sound like the gears aren't adjusted correctly, although I've checked the gear tensioner and that's OK, plus if I remove the gear cable completely so it's in top gear the same thing happens.

I thought it was the chain tensioner as the teeth on that looked very worn, so I changed that along with the rear sprocket, but that didn't fix the problem.

So, a couple of questions -

I didn't buy a new chain as the one I have isn't that old, but as I have changed the tensioner and the sprockets is it advisable that I get a new chain too?

If it's not the chain, could it be the chainring that needs replacing? I don't mind buying new parts, I'd just like to understand what the problem is first.

Anyway, if anyone can give me some advice that would be great. I hope there's enough information here, if not ask me some questions.

Cheers everyone.

 

[XC26]

Hi,

My Brompton M3L is having some problems with the gears (Sturmey Archer hub). 1st gear is fine, but as soon as I change up there's noises from the rear wheel and the pedals slip now and again. It makes a sound like the gears aren't adjusted correctly, although I've checked the gear tensioner and that's OK, plus if I remove the gear cable completely so it's in top gear the same thing happens.

I thought it was the chain tensioner as the teeth on that looked very worn, so I changed that along with the rear sprocket, but that didn't fix the problem.

So, a couple of questions -

I didn't buy a new chain as the one I have isn't that old, but as I have changed the tensioner and the sprockets is it advisable that I get a new chain too?

If it's not the chain, could it be the chainring that needs replacing? I don't mind buying new parts, I'd just like to understand what the problem is first.

Anyway, if anyone can give me some advice that would be great. I hope there's enough information here, if not ask me some questions.

Cheers everyone.

Problem occurs In 3rd with cable removed suggests the problem is with the gear hub or the little indicator chain that inserts into the gear hub's axle. Have you tried it in 3rd with little gear indicator chain removed? If problem still exists, it's the hub internals - could be a broken spring or worn out pawls.

 

[Rohloff_Brompton_Rider]

which hub? bwr,sa or sram?

 

[LCpl Boiled Egg]

Problem occurs In 3rd with cable removed suggests the problem is with the gear hub or the little indicator chain that inserts into the gear hub's axle. Have you tried it in 3rd with little gear indicator chain removed? If problem still exists, it's the hub internals - could be a broken spring or worn out pawls.

Hi XC26. Sorry I didn't reply earlier to this, as no-one replied for a month or so I had forgotten about it. It was indeed the hub internals, and as the rim on the rear wheel was looking a bit worn I just bought a new wheel. Unfortunately that was after I had bought a new rear sprocket, indicator chain and chain. Still, feels almost like a new bike now!

Oh, and it was/is a Sturmey Archer hub btw Bromptonfb. Thanks for your replies

(Apologies for replying to an old thread but thought I should explain the outcome in case anyone else has the same problem)

 

[XC26]

Hi XC26. Sorry I didn't reply earlier to this, as no-one replied for a month or so I had forgotten about it. It was indeed the hub internals, and as the rim on the rear wheel was looking a bit worn I just bought a new wheel. Unfortunately that was after I had bought a new rear sprocket, indicator chain and chain. Still, feels almost like a new bike now!

Oh, and it was/is a Sturmey Archer hub btw Bromptonfb. Thanks for your replies

(Apologies for replying to an old thread but thought I should explain the outcome in case anyone else has the same problem)

Thanks for the update. I think you chose a sensible option given that the rim was worn as well. It is possible to obtain new Bromtpon rims, gear hubs, etc and build your wheel up again but it may be no more cost effective than buying the whole wheel, as you did. Some folk prefer to delve inside the gear hub and replace, regrease the gubbins etc., deriving a certain satisfaction from fixing it themselves. SJS cyles will certainly supply you will with all the bits you could ever need, but it would require knowledge, time and experience, which is not always available.

 

[LCpl Boiled Egg]

Thanks for the update. I think you chose a sensible option given that the rim was worn as well. It is possible to obtain new Bromtpon rims, gear hubs, etc and build your wheel up again but it may be no more cost effective than buying the whole wheel, as you did. Some folk prefer to delve inside the gear hub and replace, regrease the gubbins etc., deriving a certain satisfaction from fixing it themselves. SJS cyles will certainly supply you will with all the bits you could ever need, but it would require knowledge, time and experience, which is not always available.

My LBS quoted me £40 plus parts for a hub service. I didn't ask the cost of a new rim and wheel rebuild, but I figured it was cheaper for me to buy the whole new wheel. It also means I have the old wheel, and maybe one day I'll take the hub apart and fix it myself. At the very least I might understand how it works, even if I can't fix it!