Hi all,

My deore xt rear mech has started playing up.

The lower section isn’t returning and is sticking therefore forcing my chain to go really slack.

I chained the cassette and chain thinking these may be stretched but it’s still the same, and the mech is only 12 month old which was fitted by a bike shop.

Anyone experienced this or got any ideas for things I can try. Any help appreciated as its my commute aswell as well my mountain bike.

Thanks all

Sam

Hi Sam, if the mech is not returning (sticky) I’d look at changing the cable. Or has the end adjustment screw moved which might need a tweak

A lesson I learned is to go back to the start, it’s easier to set a derailleur up from scratch than it is to faff about.

check the wheel is sat properly in the frame, check chain length if it’s new, it might be too long.

Has it been bashed, is the mech and hanger straight? Remove the chain and and losen the cable where it’s bolted to the mech. move the mech with your hand and see if it moves properly over the cassette and springs back when you let go.

If all is OK, put the chain back on.

After that, put the shifter into the smallest cog position, make sure any barrel adjusters have a good turn or two in either direction.

then tighten the cable up, it should have no slack in it but shouldn’t be tense.

Then set your limit screws.

I have reset the whole set up, and lossened off the cable and it still sticks even when moving it by hand.

I’m wondering if maybe any internals may have gone although I must admit I’ve never heard of this before??

Sounds to me like either a knackered spring or some grit in the pivot.

If I have read the op’s post right then it moves side to side (ie it shifts across) but the cage isn’t swinging back to pick up the slack in the chain. If that’s the case cable and screw fettling won’t work.

Clean the pivots up see if it springs properly pull cage forward does it swing back?

Is there resistance from the spring when pulling forward? No then the spring is probably knackered

Is the b screw broken?

Is the mech fouling the cassette?

Also do the XT mechs have a lock button on them like the SRAM mechs where you can lock the cage forward to make getting wheel in and out easier?

In hindsight, that was what was wrong with my xt mech. Shortened the chain too much to try and get some tension and then trashed it.

Sam

I have had a couple that have died that way over the years. One off rubbish spring.

Yeh if it doesn’t move properly with the chain and cable removed from the question, then it’s a problem with the mech or a bent hanger, assuming that the limit screws are not preventing it moving.

Yeah sorry my post Isn’t the clearest.

Garage dweller describes it correctly about it shifting up the cogs fine and not picking up slack.

I have stripped it down and this hasn’t helped.

Is the B screw the screw that tightens the spring? If so that’s working fine.

Jambo – how did you fix yours?

Ok, I’m guessing this isn’t something I can fix myself?

Always feel defeated when I have to go to the bike shop for help

B screw is the one that is “lengthways” along the bike at the top of the mech. It pushes against the dropout/mech hanger to push the mech back so if the top jockey fouls the cassette you screw it in and the mech moves back and down. If it’s broken or missing then that could be causing it to get snagged up and not spring properly (maybe)

My money is on it being tired spring/distorted mech and new mech time. Sorry.

I didn’t. It’s in the bin.

If it’s a clutch mech it might be worth checking the grease between the metal band and drum. It dries out / gets forced out the mech can get really notchy.