hi,

New chain, New Cassette, New chain-rings and still i cant get my gears to stop jumping. I have set up my gears using every video and bike book i can lay my hands on. I have a Shadow XT rear mech which is only a few months old. My next step is to change gear cable, although ive had it out cleaned all the outers and oil the cables.

Im not sure what else to do now. The rear mech hanger looks straight by my untrained eye. Could a few mm out of true have such a big impact on gears skipping.

Or could it be the chain length.

the gears tend to skip both up and down while under pressure. All these new bit was supposed to solve these gear issues

All this is on a Trek EX8 2009.

It's often the cable sleeves fault.
Dislodge the cables. Take the sleeve ends off the sleeves. If there's sticky out wires then dismantle the cable run and trim the ends off the sleeves. Reassemble it, giving the cable a good tug to settle it down.

i had this everytime i went over a bump on the full sus it jumped. It was the outers in the end

a few mm out on the hanger can have a big effect on your gears.

thanks every one. the outers will be inspected ASAP if not its time to find out how to check the mech hanger.

Chain slipping on sprockets or "ghost shifting"?

I had a spectral gear changing experience some time ago which was proving intensely irritating. Turned out I'd passed the cable round the wrong side of the clamping bolt on the rear mech the last time I'd fitted a new one.

The few mm (if that) of extra "pull" generated caused the missed shifts.

I would have changed cables first. The final section outer can be the most troublesome.

I had this happen, changed chain, cassette etc, then found that the rear mech. retainer screw was lose 😳
Do you have a single run of cable to the rear mech? Found this helps on full susser.
You could try changing rear mech. hanger, or you bike shop can check out if this is bent.