Chain slipping on cassette - new hub

101_North

Folks,

Just fitted a new rear wheel with an 9spd XT hub. It relaced a rear with a Deore 9spd hub. I'm using the same cassette and chain as before. They were both fitted at the same time and gave me no issues before I swapped the rear. Now the chain is slipping on the cassette whenever I put power down but only on the smallest cog. I can't see why the new hub should make any difference but I'd be happy to hear otherwise if that's actually a possibility.

The other theory I had was that the chain has been refitted in the opposite direction to when I took it off. Can't say I've ever had an issue with this before when I remove the chain for cleaning but could it be a reason?

Any advice would be great.

Cheers

101

YeehaaMcgee

Sounds like the new rear hub has a different spacing to the old one, which moves the cassette slightly to the left or right, messing up the gear indexing.
Just re-index your rear mech, and it should be fine.

Chunkers1980

Normal Chains can go 4 different ways.

101_North

Cheers. I'll have a fiddle with the indexing on the way home. The problem is very similar to a worn chain but I'm 100% sure it's not that as the same chain and cassette were OK until I changed the wheel.

Thanks for the tips

101

cycleclinic

Is the small cog on the freehub body splines properly? If it is not then the cog will catch/spin on the free hub body. Not to sure how this could arise if the lock nut is screwed on to 40 NM but you never know.

Also what cassette are you using? Some cassette require a thin 1,0mm spacer to fit the cassette properly. This also may be part of your problem as the cassette without it can move on the free hub body.

101_North

Cassette is a SRAM PG950. Should be fine on an XT hub though? I'll check the cassette on the splines but pretty sure it's installed OK - there's no obvious movement. How would I know if it needed a spacer?

Thanks

101

Chunkers1980

You don't need a spacer. Deore and Deore XT are the same width so you've swapped like for like.

101_North

Cheers. That's what I thought. I'll check the other suggestions later.

101

cycleclinic

Oh yeah you swapped hubs not cassettes. My mistake.

YeehaaMcgee

Just to clarify, when I initially said the new hub has a different spacing - what I meant was that the entire cassette may be positioned slightly closer to the centre of the hub, or closer towards the dropout than on the previous hub. I wasn't referring to the spacing in between sprockets.
I've always experienced this when changing wheels since they vary ever so slightly. You'll probably find that you'll have to re-align your rear brake calliper as well.

101_North

Thanks for the help folks. Looks like the chain was the issue after all - tried all the suggestions and then tries a spare chain and bingo. Old chain did not last well but that's another matter!

101

cycleclinic

I mis interpreted the slipping to be the chain slipping over the small sproket rather it skipping about trying to shift up or down. The latter sounds likely as pointed out. sorry for the misinterpretation.