I have a 10-speed bike and my wife an 11-speed. I have burnt enough old tyres on my indoor trainer so decided to try a trainer specific tyre on an old wheel.

The old wheel currently has an 8-speed cassette on it. What would be the effect of using that with my bike and my wife's bike? I'm guessing this would be pretty horrible.

What if I change the wheel to a 10 speed cassette (which is what I will probably do) will my wife's bike work?

My current rear cassette is 11-23 if I put a bigger cassette on say 11-28 I expect my chain would normally need to be lengthened. If I don't lengthen my chain will I just lose the use of the largest cogs or would there be worse consequences?

I have no concerns about poor shifting or missing gears because it's only on the trainer. As long as I can get in one gear that's enough, the trainer has its own difficulty adjuster. Wear on the chain or damage to other parts would be a concern.

2 Answers 2


As you suspect, you cannot use the 8 speed cassette with either bike. The indexing will be completely wrong.

8, 9 and 10 speed cassettes use the same freehub body so you can put a 10 speed cassette on the wheel. The sprocket spacing on the 11 speed cassette is different from the 10 speed, so that isn't going to work, at least not very well. Maybe you could get a few gears to work.

If your derailleur capacity and chain length don't allow the use of a 11-28 cassette, you will be OK as long as you stay off the sprockets that are too large. If you can't use a 11-28 cassette, why fit one? I guess you happen to have a spare lying around?

  • Thanks, I think a friend has a spare 11-28 10 speed cassette. I know the indexing will be messed up but for training I would be happy to ride it in single speed.
    –  mynt
    Commented Apr 10, 2018 at 5:11
  • Since it is an "old" wheel and cassette make sure it is not worn enough to shorten your chain life.
    – mikes
    Commented Apr 10, 2018 at 8:31
  • I personally find spinning at a single speed on a trainer horrifically tedious and not particularly effective. I prefer to do short hard intervals, which require gear changes. I suppose you could use the chainrings for this purpose though. Commented Apr 10, 2018 at 11:35
  • Yes it is tedious, here the trainer has its own adjustment so I plan to use that and could use the front chainring as well I suppose.
    –  mynt
    Commented Apr 10, 2018 at 23:22

Trainers are particularly tough on bikes, I too have had to cannibalize parts from several old bikes to make one working Frankenstein. If it is a road frame and of the right vintage (ie, 90's or early 2000's), it may have the mounting posts for down-tube shifters. This type of shifter can be found on e-bay for relatively cheap, and the indexing feature can usually be turned off (if it's there at all). This would eliminate the indexing problem @Argenti mentions. A too-short chain will lock you out of the big/big gear combination(s), but you shouldn't be using those anyway.

I've also found that a couple pieces of corrugated cardboard (cut in the shape of a doughnut) function pretty well as spacers when positioned between the rear cassette and the wheel, if you find yourself with a cassette that doesn't quite have the same number of gears that are meant for the hub.

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