Chain Slipping

[indeterminate]

ive just had a used xt rear mech fitted on my hybrid and now get alot of chain slipping ie dropping down to smaller sprockets after ive shifted gear
i keep having to make small taps on the shifter to correct the chain as it feels like it doesnt fit flush on the sprocket of choice and tends to roll off
The drivetrain isnt particulary worn, the mech hanger sits square, i think im getting ghost shifting?

is there any advice that this could be the cause and what would remedy it as i dont want to buy a whole new drivetrain ,chain cassette, rear mech etc

 

[compo]

Assuming that your shifters are compatible with your XT mech, then it sounds like a setting up problem. There should be an adjuster on the mechanism, try giving it half a turn anti clockwise and see what that does, then try a bit more, if no better try it the other way. Only make small adjustments at a time. the other possibility is that your cassette or freewheel and chain is worn and need replacing.

 

[indeterminate]

Thanks, im hoping its just a matter of fine tuning the set up opposed to a critical problem with worn parts as ive just spent a fair bit upgrading the bike, im presently riding in a neutral gear and just using the front mech to avoid the frustration of the chain jumping about on the sprocket
there is an adjuster on the shifter and a barrell adjuster on the rear mech, which one needs adjusting?

im not technically minded so have to rely on the judgement from bike shops

 

[the_mikey]

Either, the indexing is not quite in alignment with the cassette, set the derailleur up again! Or you have a failing cable.

 

[Nebulous]

Lots of helpful videos around. This is generally seen as one of the best ones.

 

[Chris-H]

As said above mate,its just a case of adjusting the barrell adjuster on the rear mech.

 

[Brommyboy]

Put the rear changer onto a central position then look at the derrailleur from the rear: it should be in a straight vertical line. If not, use the barrel adjuster at the cable end: anti-clockwise to pull the chain closer to the wheel, clockwise the other way. Check that the two end sprockets will be reached properly. It should then be fine.

 

[the_mikey]

ive just had a used xt rear mech fitted on my hybrid

From this information I'm assuming it's shimano XT, 9 or 10 speed, with shimano sti shifters of some kind, is it top normal or rapid-rise bottom normal configuration?

 

[indeterminate]

Thanks for the replies, ive adjusted the barrel but same problem im afraid, i checked and the rear mech looks slightly off vertical aswell
its a shimano xt 9 speed with an 8 speed shimano shifter rapid rise

ive had this problem loads in the past and it really takes my confidence away and ruins my enjoyment of riding, im afraid to put any force into the pedals for fear of a sharp slip of the chain
im going to get it all checked out tomorrow, thanks for all the help

 

[Brommyboy]

An 8 speed changer has different spacing to the 9 speed cassette! That is likely to be your problem.

 

[kishan]

the low and high screw for rear gears may need adjusting or if you look at rear mech there should be a cable running thru the rear mech turn that anti clockwise or clock wise until gears are shifting properly check below links

http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur
http://www.parktool.com/blog/repair-help/rear-derailleur-hanger-alignment