Reassembling Brompton M3L chain tensioner - help!

[LCpl Boiled Egg]

Hi all,

I've bought a new set of idler wheels for my speed Brompton M3L chain tensioner but of course I've taken the old ones apart without noting down how they go back together... Can anyone tell me what goes where or send a pic of what it looks when it's together? I seem to recall two washers next to each other, but then I can't work out where the third would go.

If it helps, the parts I have are in the attached picture. Thanks in advance,

Andy

Edit: The barrel bits obviously go in the middle of the jockey wheels, then the two pieces below either side of the wheels right? So it's down to where the washers fit I'm thinking...

 

[rafiki]

Hi all,

I've bought a new set of idler wheels for my speed Brompton M3L chain tensioner but of course I've taken the old ones apart without noting down how they go back together... Can anyone tell me what goes where or send a pic of what it looks when it's together? I seem to recall two washers next to each other, but then I can't work out where the third would go.

If it helps, the parts I have are in the attached picture. Thanks in advance,

Andy

View attachment 642684

Edit: The barrel bits obviously go in the middle of the jockey wheels, then the two pieces below either side of the wheels right? So it's down to where the washers fit I'm thinking...

https://trade.brompton.com/Uploads/QPart/QPart-Datasheets/ds-cta.pdf

 

[LCpl Boiled Egg]

https://trade.brompton.com/Uploads/QPart/QPart-Datasheets/ds-cta.pdf

Appreciate this @rafiki, but I've been staring at that all afternoon, and I still can't work out where the washers go. It seems to assume the chain tensioner is in one piece which it sadly isn't.

 

[Ming the Merciless]

Just had a look at my Brommie.

The ones with lip go either side of jockey wheel, then a washer on outside of both and bolt through the lot. The metal ring doesn’t have a washer on the outside (other side from jockey wheel). Thus I’m guessing there are two washers other side of that (that I can’t see without disassembly). The bushes through holes in jockey wheels as you surmise. That accounts for all parts shown.

 

[LCpl Boiled Egg]

Just had a look at my Brommie.

The ones with lip go either side of jockey wheel, then a washer on outside of both and bolt through the lot. The metal ring doesn’t have a washer on the outside (other side from jockey wheel). Thus I’m guessing there are two washers other side of that (that I can’t see without disassembly). The bushes through holes in jockey wheels as you surmise. That accounts for all parts shown.

Ah, that's very useful... and I did remember there were two washers together...

So it goes bolt, washer, washer, jockey wheel, washer and then bolt, metal ring, washer, washer, jockey wheel, washer for the other one.

Thank you very much, that looks good. When I fit it tomorrow, if it lines up as per the Brompton datasheet I'll be good to go. I've changed the sprocket, chainring and chain as well, so it should be easy to tell if it's not aligned correctly.

 

[rogerzilla]

The washers can be moved around to ensure the jockey wheels are in line with the sprocket.

 

[LCpl Boiled Egg]

It's all done, shifting nicely and sounding an awful lot better than it was before the weekend. Thanks for your help everyone!

 

[ExBrit]

Ah, that's very useful... and I did remember there were two washers together...

So it goes bolt, washer, washer, jockey wheel, washer and then bolt, metal ring, washer, washer, jockey wheel, washer for the other one.

Thank you very much, that looks good. When I fit it tomorrow, if it lines up as per the Brompton datasheet I'll be good to go. I've changed the sprocket, chainring and chain as well, so it should be easy to tell if it's not aligned correctly.

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