I"ve had an e-bike since last September and I have a persistent problem with the chain coming off at the front chainwheel. Its an 8 speed cassette on the back and a single chainring on the front. Happens almost every time I use the bike. Any one have any suggestions for a possible cause?
Chain coming off?
- Thread starter John Cee
- Start date
The obvious is a worn chain or damaged chain, check carefully every chain link one by one for any damage and then the front chain ring for same.
When I have had a chain come off it usually due to a damaged link, this then doesn't ride or get picked up correctly by the chain rings teeth and skews off to the side.
For less then a tenner put a new chain on to cure it, as long as you have no play in the chain ring or bottom bracket bearings.
When I have had a chain come off it usually due to a damaged link, this then doesn't ride or get picked up correctly by the chain rings teeth and skews off to the side.
For less then a tenner put a new chain on to cure it, as long as you have no play in the chain ring or bottom bracket bearings.
John you can also measure a chain to check if it is badly stretched. 1 link = 2 half links should measure 1" pin to pin or multiples of this if measuring over a longer length, if stretch is within 1/16" it is fine more means it is worn and may not be picked up by the teeth correctly.
That's a diy build.I've got an 8 speed cassette on my BBS02
I sense from John's post his is an OEM bike.
it can be derailleur cable needs adjusting, derailleur limiting screws need adjusting, chain tension needs increasing, worn chain, worn derailleur.
You have to start by eliminating a few possible causes.
Thanks for all the replies.
It's done it since new, so I guess we can eliminate wear. I took it back to the dealers in the first place and it was OK for s while, then the problem returned. The dealer is quite a way from me, so I've just put up with it since then, but it's getting really tedious now. I have tried adjusting the derailleur - didn't seem to help. Wouldn't it come off at the rear if this was the problem?
Which bike ?
I do remember some time a go someone had a chain issue and the chain was a specific ebike chain, the chain was directional and dealer had put in on backwards.
I do remember some time a go someone had a chain issue and the chain was a specific ebike chain, the chain was directional and dealer had put in on backwards.
Give them a call or owner David will be here soon, they will help you out with your issue.
Try a specific 8 speed chain as 8 sp is a fraction wider then 9 speed. If you have a 9 sp chain currently then it could be the issue.
For the Wisper use 6-8 speed Shimano HG40 Alivio or HG71 Acera or equivalent chain, locally Halfords, Evan or independent LBS, though count your existing chain links first to make sure you don't get one too short as not ebike chains are the same length.
Sram chain with quick/snap link.
https://www.ebay.co.uk/itm/SRAM-PC-830-Bicycle-Chain-Mountain-Bike-Road-Cycle-MTB-7-8-Speed-Grey-PC830/352033463332?epid=2002715785&hash=item51f6d45c24:g:voAAAOSwPc9WzwEU
For the Wisper use 6-8 speed Shimano HG40 Alivio or HG71 Acera or equivalent chain, locally Halfords, Evan or independent LBS, though count your existing chain links first to make sure you don't get one too short as not ebike chains are the same length.
Sram chain with quick/snap link.
https://www.ebay.co.uk/itm/SRAM-PC-830-Bicycle-Chain-Mountain-Bike-Road-Cycle-MTB-7-8-Speed-Grey-PC830/352033463332?epid=2002715785&hash=item51f6d45c24:g:voAAAOSwPc9WzwEU
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KMC Z51RB 116 links is the original chain supplied.
https://www.ebay.co.uk/itm/KMC-Z51-18-24-speed-quality-bike-cycle-chain-3-32-with-split-link-6-7-8-speed/273176728403?epid=1605256625&hash=item3f9a9a1353:g:NhQAAOSwEg1a30sD
https://www.ebay.co.uk/itm/KMC-Z51-18-24-speed-quality-bike-cycle-chain-3-32-with-split-link-6-7-8-speed/273176728403?epid=1605256625&hash=item3f9a9a1353:g:NhQAAOSwEg1a30sD
If the chain is falling off the front cog, how about trying one of these.
https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR12.TRC2.A0.H0.Xchain+guide.TRS0&_nkw=chain+guide&_sacat=0
Works for me.
https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR12.TRC2.A0.H0.Xchain+guide.TRS0&_nkw=chain+guide&_sacat=0
Works for me.
I had similar problem with Pendleton from new, with chain falling off onto the outside every approx 70 miles or so. It seems to happen often after long freewheeling down hills. I initially tried tightening B screw but made no difference. I then tried removing two links from chain and this reduced the incidence.
In the end, after carefully observing chain on rides, I noticed that chain slaps around quite a bit from side to side, especially the top horizontal section when freewheeling and when on the highest 13 cog.
The bike has a chainguard and I made an improvised chainguide with a cable tie, which limits (and damps) the side to side chain slap, and this seems to have eliminated the problem.
Note. The pendleton has a long wheelbase (19 inches between BB and rear axle c/c) and has a 118 link chain. (38/13 eight speed)
Finally, its very important to switch off bike before refitting chain.
In the end, after carefully observing chain on rides, I noticed that chain slaps around quite a bit from side to side, especially the top horizontal section when freewheeling and when on the highest 13 cog.
The bike has a chainguard and I made an improvised chainguide with a cable tie, which limits (and damps) the side to side chain slap, and this seems to have eliminated the problem.
Note. The pendleton has a long wheelbase (19 inches between BB and rear axle c/c) and has a 118 link chain. (38/13 eight speed)
Finally, its very important to switch off bike before refitting chain.
D
Deleted member 4366
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Single chain-wheels don't always work very well with 8-speed or more unless the chainwheel has a guide to stop the chain coming off. You can use a front derailleur, a chain guide or even a chain guard in some circumstances.
It's possible that you don't have enough tension in your chain because it's too long. We need photos to give exact advice.
It's possible that you don't have enough tension in your chain because it's too long. We need photos to give exact advice.