9 speed wheel on 11 speed bike for the trainer

I have a new 11 speed bike and a wheel on trainer I’ve been using. Changing to my trainer tire is a pain every time I want to ride inside versus out.

What considerations are there if I just leave my trainer tire on my old bikes 9 speed wheel and pop that on the new bike? Would the indexing be seriously messed up? I’d make sure I didn’t shift into the spokes, assuming the limits on the derailleur are different.

Yeah, the indexing is off. I’ve done this 10->8 with a wheel-off trainer, but I just left it in the one gear that worked and used ERG mode.

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Is the trainer a smart trainer? Do you exclusively use erg mode? If yes to both then it may work as long as you find the right gear that minimizes indexing.

If you can afford it, though, I’d get a super inexpensive rear wheel and 11-speed cassette just for the trainer.

  • On par with this, assuming the current trainer wheel on hand is not dedicated to any other use, it’s possible to put on the 11-34 11-speed Shimano cassette that fits on the older 9/10-speed cassette bodies. It’s a less expensive way to leverage the current wheel to make it a much better matchup, especially if there are reasons to use more than one gear for modes other than ERG.

Is an 11 speed chain different from a 9 speed chain?

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Yes, the 11s is more narrow.

ETA: Compatibility [01] Chains | BikeGremlin

  • 9 speeds: The chain width is about 6.7 mm.
  • 11 speeds: The chain width is 5.62 mm.
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No erg mode; using Kurt kinetic road machine.

I’ll look into that cassette option, does it need to be that gear range? I don’t have a long cage derailleur, I believe the max supported range is 11-30 (ultgra r8000). Though I could just avoid shifting into the lower gears.

If you avoid using the lowest gear (34t), you should be fine with that cassette. Depending on the current chain length and B-Tension you have set, the 34t might work OK, but I’d be cautious in testing it if you want to see. Otherwise, that 30t next to lowest should be functional to give you 10 good gears.

And just to make it clear, I mentioned that specific cassette because it is the only Shimano branded cassette that is 11-speeds, but functional on those older 9/10s cassette bodies. I am presuming the wheel you currently have the 9s on is not the latest and greatest HG 11s road cassette body. However, if that wheel has a modern 11s cassette, you can run any of the normal 11s HG road cassettes. So, it may be worth removing the 9s cassette to see what you really have under it.

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Yes whilst they are identical on the inside the 11sp chain has thinner side plates to make it thin enough to fit on a tighter 11sp block. Whilst you could run at a push an 11sp chain on a 9sp cassette you couldn’t do it the other way round (fit a 9sp chain on an 11sp cassette).

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Alternatively, just ride a normal tyre on the wheel-on trainer. You don’t need absolutely need a trainer tyre. You might get a bit more wear on the tyre, but it works just fine.

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True, I just try to avoid using my gp5ks in the trainer so I don’t burn through them as fast