Gears jumping only when using rear suspension

[Cerburus]

I have recently built up a full sus Specialized Stumpjumper FSR M4.

I have set the gears up so they are running very smoothly with the rear suspension unit locked off.

However as soon as I unlock the rear suspension my gears start jumping.

My running gear is Deore Shimano 44Ax32Ax22A with 9-speed 11x34t rear cassette using Deore XT top normal mega 9 rear derailleur using SLX rapidfire shifters.

I am having to ride mostly with the rear sus locked off just so I can ride. So all I have is an expensive hard tail.

Does anyone have any ideas what could be causing this.

Cheers

Cerb

[Painkiller]

try playing with your b-tension screw

[RobAR]

It sounds as though you have a problem with the cable routing. If you have an air shock, let the air out so that the swingarm can move through its full travel and watch the rear drlr. If it tries to move, study your housing and be certain that you didn't miss a stop or cut a section too short.

Rob

[Cerburus]

Hi Rob.

You were correct. The piece of cable outer between the last stop on the downside of the A frame and the first stop on the swing arm was too short.

When the swing arm moved the cable was put under tension and was trying to change gear.

I replaced the cable outer with a slightly longer piece and problem solved.

Nice one. Smooth shifting from here on in.

Cheers

Mike