Hi guys,
I have an XT rear mech with 9 speed XT cassette, 9 speed LX shifters and a 9 speed chain which is within wear limits.
I can shift inwards (into lower gears under tension) just fine but when it comes to dropping back down (into higher gears) it wont shift 1 gear per 1 click of the shifter.
The jagwire gear cable is only about 4 months old.
With the chain off and the back wheel out the mech moves freely by hand.
I end up having to click down (up a gear) a couple of clicks for it to move one then try to re align the mech by clickin back up one.
Its a pain in the tits and i often find it slipping when putting the power down, it seems worse in 2nd-5th gears on the rear cassette.
Any thoughts?
Cheers
Col
1st thing to do is check gear cable tension. Make sure when the cable is at it's slackest it's just taut enough to not be flopping around, no tighter, no looser.
2nd. check the alignment of the mech/hanger.
Most likely to be the cable, possible, but unlikely to be stiff mech pivots or a dodgy shifter(try a bit of GT85 on the mech pivots/ light spray inside the shifter), 4 months life isn't unheard of for an unprotected gear cable in the conditions we've had. Probably worth fitting a full length of Shimano SP41 outer with sealed SP4 end caps, and a good quality stainless inner for the long term.
Thanks for the replies guys, It is a bit better now, I slackened off the cable at the mech (bolt clamp) wound the barrel adjuster 2 turns out from fully home put the cable back in the clamp and put it under a minimal amount of tension. Clamped it up and tried it, fettled the barrel adjuster a little and it is better than it was.
Thanks again
Another thing to consider is that your mech hanger may be bent slightly causing your poor shifting.
It appears to be ok with the mech lining up niceley at the inner and outer gears so I'm guessing the hanger is ok....?
Most likely dirt/grit in the cable housing. If all else seems ok I'd replace the cable and cable housing. Not expensive or difficult to do, you may even get away with using the 4 month old cable if you give it a clean and it's not frayed at all.
Had a similar problem yesterday, could go from 10 to 1 (hard to easy) perfectly, but a click from 1 didn't cause a shift, tho the mech moved, then a second click would go straight to 3.
Eventually I figured out the cable sheath itself was a bit short between the last stop and the mech, stopping the cable from releasing enough tension. when I pulled a couple of cm of sheath down through the stops it sorted it.
Basically, if its shifting up the block (hard to easy) ok but not the other way, it's likely all your alignment and cable tension is good. The mech relies on release of cable tension to move back down the block, which it takes in via its spring - but the spring only has so much power. Something is stopping or reducing release of tension and the spring is not strong enough to take it (all) in.
Change the cable, inner and outer.
That's what I'd do, and I see a lot of mis-shifting mechs.
APF
For the record, my problem wasn't fixed by changing the cable or outer. It turned out the B screw was miles out (I didn't install this mech).
I slacked it off as per the instructions
and the shifting worked perfectly straight away.
(Which then drew attention to how rough the BB is on this bike, but that's another story).