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I ride a Cannondale Topstone outside during the warmer months and then on a Wahoo Kickr when it gets cold. When I put the bike on the trainer I get a grinding noise and vibration when in some gears. It's not a crunchy grinding as if there's some debris in a bearing, but rather it feels as though the chain isn't riding over the rear sprockets evenly. I have identical clusters on both the bike wheel and the trainer. I will say that the wheel cluster has many more miles and harder miles on it. New chain last spring with only about 800 or 900 miles on it. This is a through axle setup, so it isn't an alignment issue, I don't think. Many gears are just fine, but the middle section gives the vibration.

I had it at a shop and they were unable to resolve the issue.

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  • Does it shift properly and smoothly? Just to rule out a rear derailleur alignment issue. When you turn the crank very slowly with your hands, does it look like the chain is engaging smoothly with the cassette? On my Ultegra R8000 11 speed I’ve found that the sprockets are extremely close together with very aggressive teeth which tend to catch the chain ever so slightly. Apart from slight vibration and noise it didn’t cause any issues and went away over time (probably due to wear of the teeth).
    – Michael
    Oct 4, 2021 at 13:39
  • @Michael I'll check that out. It does seem to shift smoothly, aside from a bit of wonkiness that I introduced as I tried to get rid of the grinding.
    – That Idiot
    Oct 4, 2021 at 14:15
  • Can you provide a link to a picture of the trainer? Oct 4, 2021 at 14:36
  • Actually, I think it is possible that it’s an alignment issue in this sense: the freehub’s lateral position may differ slightly between your bike and your trainer, or more generally between different hubs. That said, the noise produced by indexing off tends to be more chain skipping or wanting to make a shift than grinding.
    – Weiwen Ng
    Oct 4, 2021 at 15:10
  • @ThatIdiot out of curiosity, you accepted my answer, but does that mean that the suggestions actually resolved the noise and vibrations? Oct 5, 2021 at 11:10

1 Answer 1

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I get a grinding noise and vibration when in some gears...
Many gears are just fine, but the middle section gives the vibration

I had this exact issue on a wheel mounted cassette (on a bike, not a trainer). The sound was there only under load. Replacing the cassette and the chain resolved the issue right away.

My understanding is that one should change the chain when one changes a cassette as these components wear out "together", making them "accustomed" to each other.

When you put the bike on the trainer you effectively replace the cassette. As the trainer cassette is less/differently worn than the cassette on your bike, the chain fits slightly different, creating the noise and vibration you experience.

If I was in the same situation I would either:

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  • - Adjust the indexing by 1/4 to 1/2 turn of the barrel adjuster.
    – Carel
    Oct 4, 2021 at 16:07
  • @Carel feel free to edit my answer to add that point, I am not sure what turning the barrel adjuster would change in this situation. Oct 4, 2021 at 17:14
  • The answer of ''use different chains for indoor and outdoor'' is very good advice here.
    – JoeK
    Oct 4, 2021 at 20:51
  • I find I need to tweak my H/L limits when I switch from trainer to wheel. I chalk it up to tolerance differences in the DS spacing.
    – P. Barney
    Oct 4, 2021 at 21:59

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