fitted a 36 slx ring to atlas cranks and it feels like the free hub is slipping under load in small cogs on the rear. Changed rear wheel. Still doing it. The ring needed a little grinding to get it to sit on the crank arms with out fowling the shoulders of the crank arms. Tried different bolts. Chain is quite new and the rear cassettes are ok. It feels as though the whole chain slips a link or as if the free hub is knackered. Any ideas other than buying a ring that fits properly.

Could be the pawls inside the freehub or more likely its jumping on the smaller sprockets as the cassette as its knackered – all of the cassettes I have replaced in recent memory have looked fine but worn non-the-less.

Did this problem start as soon as you changed the chain ring or before? What did you change it from? if the ring is bigger your creating a larger torque and so will be more likely to jump on a worn cassette?

Chainsuck with new ring and old chain? Is the chain meshing properly with the new chainring?

Might also be worth seeing if the chain is catching on the outer ring / bash when you are in those small sprockets – I had that before when I fitted a Middleburn outer to my XTs; it was too close to the middle ring and the chain would catch on the shift ramps when in the small sprockets.

I suppose the best way to investigate is swap the old ring back on, see if there is still a problem; if not, it's some meshing or alignment issue with the new ring.

yeah will try the old one again but i know it wont do it with that one on. Its not the pawls or free hub as ive swapped wheels around and it still does it. Im going to try shouting at it later this evening.

Sufficient chain wrap-round?

Chain is quite new and the rear cassettes are ok.

New chain on an old cassette? It maybe that although it looks OK, the cassette's actually knackered.

I think nickc has the likeliest explanation.

or me 😉

or more likely its jumping on the smaller sprockets as the cassette as its knackered – all of the cassettes I have replaced in recent memory have looked fine but worn non-the-less.

Obviously user error 😀

is the ring on back to front? If it needed grinding it might be. That could make the chain climb off in the small sprockets and ride up between the ring and the bashguard.

Probably cassette/chain issues, but worth double checking the indexing and b post tension.

nickc – Member

Chain is quite new and the rear cassettes are ok.

New chain on an old cassette? It maybe that although it looks OK, the cassette's actually knackered.

+1 for nickc and TJ

Remember the problem has only started since I fitted the middle ring so why should rear cassette condition affect it. Plenty of wrap around but I could give it some more and I have tried different wheels cassettes and chains. The middle ring is on the right way round and the bash guard is plastic and not touching the chain when on the smallest rear cog. I often use components well past their best and never has a chain slipped on a cassette. It feels exactly like the pawls need replacing but pop the wheel in another bike and grunt. No slippage. Put that bikes wheel in and there it is.