gear problems sram x9

mowzer

This is doing my head in !!!
I've replaced the cassette and chain on my 2009 stumpjumper fsr comp
when the bike is up on the stand i can get the gears running perfect
but as soon as i take it for a ride the chain jumps all over the place and tends to pull the rear derailleur up into the cassette. :?
can this be that the chain is too short? i followed the park tool website to get the length.
anyone had the same problem?

nicklouse

the mech is being pulled to the wheel. then the cables have too much friction in them or are trapped and as the sus moves it is forcing the mech to move.

mowzer

so do you think the cable tension is too tight?

Neal_

If the cable tension was too tight it wouldn't be indexed correctly in the work stand. The problem is usually due to friction in the cable (as nicklouse said) so replace the inners (and possibly the outer) lubing them and the bottom bracket cable guide. If this doesn't work clean and lube the rear mech as sticky parallelogram pivots can cause shifting problems and check the mech hanger isn't bent. I doubt chain length would be an issue unless you are in big ring big cog but chain and cassette wear could cause problems.

mowzer

Thanks
i'll give replacing the cables a try.

nicklouse

mowzer wrote:

Thanks
i'll give replacing the cables a try.

first check that nothing is trapped damaged or too short.

as if you just replace things exaclt the same you will have the same problem.

put bike on ground and apply pressure to the sadle to work the suspension while looking at the mech.

is it being moved? yes! then that is your problem.

ashleydwsmith

Is it a SRAM cassette?

I've had a similar problem, I bought a SRAM cassette on sale from CRC, lbs got it setup, running sweet in the stand. Out on the trails all over. Took it back to the lbs and its a fault with the cassette. ( the guy in the lbs is an ex SRAM tech do knows his stuff)