Chain slipping

colinsmith123

New Shimano 10 speed chain and cassette fitted, but the chain is jumping off the front 34 ring when i'm in any of the 13; 14;15 16 sprockets when moving off from a start or applying load on a hill.

I've checked I have not got a stiff link, indexed the gears up and down, and in and out, and round and round. Short of getting the micrometer out to index the gears I'm at a loss to know what to do next.

Seeing as I bought the chain and cassette fro Ribble, I can't blame Wiggle.

andrew_s

It sounds like you need a new chainring.
Chainrings wear out just like sprockets do. Once a chainring has slipped once, it will slip much easier next time, to the extent that it can slip on normal seated riding. A bit irritating if your route is flat out, hilly back.

Ouija

+1

New chain, new cassette but old chainring means the distance between the back edge of the teeth on the cassette and the front edge of the teeth on the chainring are slightly out of whack (short), causing the slipping under load. By and large, since the chainrings spin and wear down slower you can often get through three or four rear cassettes before the mismatch becomes a problem. As a temporary solution until you get some more chainrings you can slap the old rear cassette back on for a few weeks and see if that meshes any better. Just don't use it as a permanent solution as it can make the situation worse.