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View Full Version : HELP! Cycle chain/cassette problem!


Ian
25th January 2017, 10:31 AM
As part of my fitness regime I invested in a turbo trainer for my hybrid bike last year. I later bought a used wheel with a trainer tyre (blue, smooth (quiet) tread-less finish). This is a great improvement but I have a problem - I can only just about run the trainer wheel in one gear as the chain slips on the other cogs.

It has 8-speeds (my road wheel is 6-speeds, 18 in all with the three front cogs). The cassette looks to be in good condition though I suppose it could be worn out? Being used inside all its life it's not likely to get dirty. I do wonder if the standard chain is not the right fit - how can I check this? Should I change the cassette and if so, how will I know which spec. to get?

Any advice is very welcome :)

Ian

Cerebus
25th January 2017, 10:41 AM
Hi Ian, cassettes and chains are usually replaced at the same time and using the same chain for 2 different cassettes usually doesn't work very well.

Also, a 6 speed chain is probably not compatible with an 8 speed cassette in the first place.

So what I would do is to get a new 8 speed chain + 8 speed cassette for your trainer wheel. To avoid compatibility problems, I'd stick with either SRAM for both or Shimano for both, although in theory SRAM and Shimano are cross -compatible.

8 speed cassettes and chains are quite economical; you pay a premium for 10-speed and 11-speed.

Cerebus
25th January 2017, 10:45 AM
Forgot to mention: SRAM chains come with a "powerlink", which is relatively easy to install/deinstall without special tools. Not sure if Shimano have a similar system.

Ian
25th January 2017, 10:53 AM
I know nothing, so thanks for the advice, however - if I change the chain and cassette, won't that mean a lot of complication when swapping between road and trainer wheels?

The bike is 25 years old and has a Shimano setup. The trainer wheel is Shimano, but no idea if the cassette is also. I have never felt the need for more gears than 3+6 but that may be due to ignorance :D .

Ian

Cerebus
25th January 2017, 11:55 AM
Yes you would have take out the road wheel (6 speed) + disconnect the existing chain and then mount the trainer wheel (8 speed) and connect the 8 speed chain.

Alternatively, you could try to install a 6 speed cassette (instead of 8 speed) on the trainer wheel and run both wheels with the same chain - as I said before this might not work very well because cassettes and chains "mold" to each other as they wear and trying to use a new cassette with a worn chain usually leads to problems.

Please note your front chainring may be worn as well if your bike is that old. I would suggest visiting your local bike shop and discuss with them what you want to achieve. You might have to speak to the mechanic. If you have an Evans Cycles nearby their mechanics should be knowledgeable about this.

I agree you don't really need 11 speed cassettes etc. so if you're happy with 6 stick with it. As a bonus it means that any components you need to replace are cheap.

Ian
25th January 2017, 12:19 PM
The bike is old but it hasn't done that much mileage :D Hoping to put that right!

Ian

PaulB
25th January 2017, 09:56 PM
Chances are your 6 speed wheel has a screw on freewheel and not a cassette.
6 speed cassettes were only available for a couple of years and won't be compatible with your 8 speed hub.
8 speed chain is the same width as 6 spd so should work with both systems but the indexing (distance the shifter moves the chain across the sprockets) may be different for the 6 and 8 speed blocks and that's why the 8 spd will only work in one gear.
Sorry I can't offer any good news. :(
Might be easier swapping the tyre or buy a cheap second hand bike to leave on the trainer.

Ian
26th January 2017, 11:36 AM
Chances are your 6 speed wheel has a screw on freewheel and not a cassette.
6 speed cassettes were only available for a couple of years and won't be compatible with your 8 speed hub.
8 speed chain is the same width as 6 spd so should work with both systems but the indexing (distance the shifter moves the chain across the sprockets) may be different for the 6 and 8 speed blocks and that's why the 8 spd will only work in one gear.
Sorry I can't offer any good news. :(
Might be easier swapping the tyre or buy a cheap second hand bike to leave on the trainer.

Thanks Paul. My bike has a very simple lever gear-change, it's not click-stopped so it's completely 'analogue' for both ends of the chain. (So guessing 'indexing' is s red herring?) I'm now suspecting that the cogs on the trainer wheel are heavily worn? The previous owner clearly used his trainer a lot and was upgrading to a more sophisticated type. Maybe I should try a replacement 8-speed cassette?

Ian

PaulB
26th January 2017, 05:14 PM
Apologies, I mis-read the slipping bit. If the indexing is off the chain "chuckles" and slips off the sprockets.
A new 8 spd cassette can be had for 9 at Halford's and not having indexing you can feel the gears in.
Changing cassettes needs a special tool and chain whip so will be a shop job if you don't have or can't borrow them.

Ian
27th January 2017, 10:10 AM
I think my lofty ambitions of doing a DIY job will have to face reality :) To the shop (or our local visiting bike mechanic) it will be.

Ian