Carrera Vulcan E-bike - chain slap

[richardadc]

My 3yo Carrera Vulcan with the Suntour HESC system has just today developed a loose chain when coasting. This is resulting in chain slap and the chain coming off frequently.
It was quite a sudden change in that it was absolutely fine and then about a mile in to the journey every time i was coasting the chain was slapping against the chain stay even on flat ground. Going on bumpy ground resulted in the chain falling off a few times.

If anyone has got any ideas what may have caused this please let me know.

 

[soundwave]

try a new chain

 

[richardadc]

try a new chain

If it was the chain wouldn’t it of not come on so suddenly? I would have thought that is something I would have noticed getting worse over time.

 

[soundwave]

chains stretch over time but you can get a tool to check them

Park Tool CC3.2 Chain Wear Indicator | Sigma Sports

Shop the Park Tool CC3.2 Chain Wear Indicator online at Sigma Sports. Receive FREE UK delivery on all orders over £60 and easy returns!

www.sigmasports.com

if it is 3 years old its time for a new one

 

[richardadc]

Just to be clear the chain has gone from being fine to literally now resting on the chain stay when coasting in the space of 10 minutes. I understand chains stretch but surely not like that? Before today i wasn't getting chain slap even on bumpy grounds, today I'm getting it on perfectly flat ground.

Googling seems to suggest an issue with the freewheel but not sure what this means for a bike with an electric motor in the rear wheel?

 

[soundwave]

take a pic but is there any way the wheel has moved forward?

 

[sjpt]

If the freewheel is slightly sticky and you aren't pedalling very hard
1) the motor will turn the wheel forward,
2) and that will turn the freewheel forward,
3) and give you lots of slack on the top section of chain.

You might get similar effect on a non-e bike, but the motor will make it worse.

 

[soundwave]

 

[vfr400]

The Carrera Vulcan has a cassette motor. What's happened is that the cassette is not free-wheeling properly. Maybe some grass is caught between top gear and the frame or some dirt has accumulated somewhere, or it just needs oiling.

 

[richardadc]

I just went out and had a good look over it. All seemed fine so took it out for another ride and while the issue was still happening it wasn’t anywhere near as bad as before. I took a video at https://photos.app.goo.gl/nfE3sDKbTQ89VMZF7

10 minutes into the ride and the issue completely disappeared. I’ll keep an eye on it but maybe something was stuck somewhere.

Thanks all for the advice. I certainly learnt something new today at least.

 

[soundwave]

it is still not right as that chain is wagging like a dogs tail not surprised it is falling off esp on bumps.

 

[richardadc]

it is still not right as that chain is wagging like a dogs tail not surprised it is falling off esp on bumps.

I meant that was how it was at the start of the second ride. On the first ride the chain was completely touching the chain stay. Not long after that video the chain went back to not having any movement and stayed that way for the rest of the 30 odd minutes i was using it.

 

[soundwave]

well id get that free wheel of and give it a clean esp if it has not been done for 3 years.

 

[richardadc]

well id get that free wheel of and give it a clean esp if it has not been done for 3 years.

You're probably right - i think it could probably do with a good service in general. The only real maintenance I've done is cleaning and oiling the chain - everything else has just been fixed when it breaks.

Thanks for the help.

 

[soundwave]

tbh id just buy a new free wheel and chain and bin what you have as cant be that expensive to get new ones.

 

[TheoFitz]

I had the same problem. I remove the freehub and found one of the bearings in the freehub was faulty. There are two bearings. I removed the three little lugs on the hub so as not to lose them. I removed the circlip and hammered out the bearings with a plug socket. Ensure what you use is a slightly smaller diameter of the bearings. The bearings are press fit with a spacer between them. I hammered in the new bearings, don’t forget the spacer.
I replaced them with Enduro 6001RS bearings (£12 for the pair).
I don’t know if there is a difference between these bearings and the cheaper brands but the time it takes to replace the bearings, I rather be cautious. Time will tell. All is working well (for the last 3 months).

 

[Nealh]

6001rs are cheap you can buy then for a little over a £1 each.

 

[TheoFitz]

6001rs are cheap you can buy then for a little over a £1 each.

Yes as I stated there are cheaper ones but for the time it takes I decided to use more expensive ones.

 

[vfr400]

I had the same problem. I remove the freehub and found one of the bearings in the freehub was faulty. There are two bearings. I removed the three little lugs on the hub so as not to lose them. I removed the circlip and hammered out the bearings with a plug socket. Ensure what you use is a slightly smaller diameter of the bearings. The bearings are press fit with a spacer between them. I hammered in the new bearings, don’t forget the spacer.
I replaced them with Enduro 6001RS bearings (£12 for the pair).
I don’t know if there is a difference between these bearings and the cheaper brands but the time it takes to replace the bearings, I rather be cautious. Time will tell. All is working well (for the last 3 months).

Nice one. Thanks for the info.

 

[TheoFitz]

Just an update. The 6001RS bearings lasted about 6 months. I have since installed Enduro RS60012RS from Simply Bearings and all seems well. I noticed that the load spec. for the 2RS is greater than the RS bearings. The original bearings were 60012RS.