When I shift gears to the smallest sprocket it makes a very loud clunk sound. There's also a lot of movement in the chain, like a bounce. I've taken a video demonstrating this Video of clunk I'm moving off the smallest sprocket then back down.
Bike is about 8/9 months old, but only used regularly the last 5 months and has a GRX400 groupset.
- It occurs when I'm either on the big or small chainring (which I think would rule out the chain being too tight?)
- Gearing is otherwise fine apart from this, although there is a bit of clunking moving to the second and third smallest sprockets as well, but not as bad.
- It occurs with the clutch on or off.
- It also happens riding on the road and on a turbo trainer.
- There's no interference from the front derailleur.
- The derailleur is a direct mount and it doesn't look bent in any way.
- It has a 10 speed cassette and I can see a spacer behind the cassette as expected.
What I've done/checked:
- The cassette is torqued to at least 40nm. There is a tiny bit of movement/play with the cassette but I believe that's normal.
- Reindexed the gears and confirmed low and high limits are correct.
- The route of the chain through the rear derailleur is correct.