GRX on my new bike is great except for one thing: when pedalling over bumpy ground it keeps momentarily shifting into the next gear. It’s 1x, and seems to only happen in the higher gears (smaller sprockets). Have checked hanger alignment, don’t think I can go any shorter on the chain, and clutch is on. The shifts seem to be into a higher gear, although I’m not sure it hasn’t gone the other way too. Seems to be more of issue with small fast bumps rather than big hits.

Anyone else had this? Any suggestions?

I’ve heard of a couple of people having clutch issues on the new grx. One rebuilt his, the other had it replaced under warranty. Worth a check

The clutch seems to work, but there’s a small amount of free play before it kicks in. As far as I can tell, my XT clutch mech is the same.

There’s also seems to be a bit of play in the pivot at the top of the cage, but again, my XT mech seems the same, and I can’t get it to shift when waggling it around on the stand.

If its full suspension are you sure the cable outers are long enough to prevent them coming under tension as you move through the range of travel?

If its full suspension are you sure the cable outers are long enough to prevent them coming under tension as you move through the range of travel?

Was my first thought, had similar issues a long time ago on a full suss bike.

My GRX will drop into one of the higher gears if I backpedal, probably due to chainline.