Wheels-on Trainer Peeve

Question for fellow wheelies - I have a Kickr Snap that has served me well for a couple of years, but the BUMP annoys me like a drip torture.

What is the bump you ask? (obviously you’re a non-wheelie, aka “direct drive” user, aka obscenely wealthy). The BUMP occurs whenever the valve point on the tube contacts the trainer drum. So…a lot.

Anyone else deal with this, or more importantly resolve it? I’ve tried higher and lower pressures, tightening the valve stem nut down, loosening the nut, and removing the nut entirely. Would :heart: to know how to fix it.


I used to have a Snap but NEVER had that issue. It’s exactly the kind of thing that would have driven me bonkers. Well…more bonkers.


Well $&@% @Glen.Coutts, that’s what i was afraid of. That it’s NOT a thing and is fixable. Back to tinkering.


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I’d try a different tube, different tire (I used only trainer tires) different wheel (if you have one). Do you warm up the trainer prior to starting a vid? I would ALWAYS do a 10 minute fairly easy spin followed by a spin down calibration before every single ride.

I had a dumb-trainer until last Sept. I can’t say I ever had that bump. That doesn’t sound good. :thinking:

I would be checking that the base of your valve stem is up inside the tire belly, above the tyre beads and not sitting below causing the bump. On the road you wouldn’t notice the bump because the road is , bumpy, but on the trainer it would be very noticeable, as you’ve found!

Ps. I’ve used both versions of tire / tyre to try and keep everyone happy!!

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Your tyre isn’t seated correctly.

Definitely fixable (and not really related to the trainer - if your outdoor bike had this issue I’m not sure you’d be complaining about your “road peeve”).


What size tyre are you using? Is it a turbo specific tyre? What pressure have you set it to?

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I have a dedicated indoor Shimano rim, 23mm vittoria trainer slick, usually run 90-100psi.

I’m going to tear it down today, check the tube and the bead. Maybe try to mount it on a road rim, though I hate to put trainer stress on my road rims.

Thanks all for the input. So tore down the wheel and found out the rim had cracked in three spots. was an old rim I only used for the trainer, but yeah… :grimacing:

Swapped out one of my road wheels with the training slick t(y)re and voila. No bump. Added bonus that the bike was tuned to that wheelset this year, so shifting is much improved. Not thrilled with extra wear-and-tear on the road wheel, so will look for a replacement rear, but there you are.