hi all. just recently fitted a new sram x9 and pc991 chain to my bike and set the gears up. But when im out on the trail when i come to a climb and have to put alot of pressure on the pedals it starts skiping! But if i am riding along at a gentle pace or turn the bike upside down and spin the pedals while changeing gear its fine. Any suggtions on what it could be would be much appreciated. ITS DOING MY HEAD IN!

you changed the rear cassette, if not how many miles has it covered?

nope i havnt changed my cassette. not sure how many miles its coverd but i have had the bike for about a year & a half and it gets used nearly every weekend at the likes of glentress red & whinlatter red routes! Do you think it could be worn. it dose'nt look worn. thanks.

When I change the chain I also pop on a new cassette too, that way they wear in/out together & I've not had an problems.

If you have been riding for a year & a half on the same cassette then i'd say it's probably time to change the cassette to a new one especially as you have a new chain.

yes
Definitely new cassette time. Unless you change the chain before it gets too worn you end up having to get a new cassette as well

Why are you changing gear under lots of pressure? That is one sure fire way to snap the chain.

I concur, a new cassette is probably required.

By spinning your pedals at an easy pace, or upside down won't pull the chain hard into the cassette, but once you start climbing, the chainlinks won't be able to sit correctly in the cassette because of the gaps created by the wear.

As a rule you should change the cassette every 2nd chain, assuming (as Mike points out) you haven't let the chain become overly worn.

so do you think if i put my old chain back on untill i get a new cassette it would stop skiping? thank guys.

that might work give it a go. If it stops skipping then you know where the problem is

Goan – Member
Why are you changing gear under lots of pressure? That is one sure fire way to snap the chain.

When did he say he was changing gear?
Might be worth getting a tool for checking the chainlength (one of those things that make a good birthday/Christmas present) to keep an eye on things.

yes, new cassette or possibly new jockey wheels

And when you've fitted the new cassette, you might find that the skipping moves to the fronth then, ususally the middle chainring.

Thanks for the advice people. Put my old chain back on for the weekend and the gears stoped skiping so it must be a worn cassette. Much appreciated.