Rear Derailleur, Make it work Options

[BarçaBike]

Right, I'm doing something wrong. Don't know what it is but it's definitley wrong as the rear der. isn't changing properly. It goes up from the smallest sprocket (highest gear?) to the biggest no problem, just on the way back down it either doesn't change or skips or jumps a couple at a time. so far i've tried

i) tightening the cable
ii) jiggling the barrel adjusters
iii) playing with the limiting screws
iiii) stroking it and cooing encouragingly.
v) taking it to the bike shop and looking at other derraileurs in front of it

None of the above seems to work.

Help? (it's a 2008 XT shadow by the way...)

[Freester]

First of all try a new cable.

With shadow mechs check that you have a bit of slack in the last stretch of outer - too short and you'll never get high gear.

Worst comes to worst check the hanger isn't bent.

But first of all... How old is your cable?

[BarçaBike]

´bout two weeks old, shop fitted.

[Mad Pierre]

Its not indexed right or the cable is sticking. If its a new inner AND outer then its probably the first.

As you've been fiddling do the the following:

(Best done in a work stand)

Wind all the barrel adjusters in (turn them clockwise) so the cable is as slack as it will go. The cable should only be hand tight now. If it is any tighter then undo the clamping bolt on the rear mech and re-tighten with it so.

Set the limit screw on the smallest cog. Look at the mech from the rear and adjust the screw so that the mech/chain is lined up with the smallest cog and can't go any further towards the drop out.

Set the limit screw on the biggest cog. Don't shift the gears - just push the mech across with your hand while turning the pedals and then adjust that limit screw so the mech/chain is lined up with the biggest cog and can't go any further towards the spokes.

Now shift up and down the block a couple of times. Chances are it won't quite shift up to the biggest cog properly and will be sloppy coming down (not enough tension). When coming down the block from biggest to smallest cog - count the clicks to see which gear you should be in and stop when you should be in the middle of the block. Check things by looking at the cassette from the rear again. Increase the tension by tightening the barrel adjuster until the mech/chain lines up properly with the cog you should be in.

That should be about right. Give it a try.

[daniel_owen_uk]

My bet is on the cable, they get covered in mud and goop.

On the way up, you are pulling the cable (with the shifter) so it doesn't have much choice but to go where you tell it. On the way do all you are doing is releasing the tension, so if it's clogged up then it just won't fall the same.

Clean it all out and then try reindexing.

[BarçaBike]

Cheers all

Haven't tried it yet as still to get a workstand. I thought fixing stuff myself would work out cheaper, not bl**dy likely...

p.s - Mud? What's mud? Is it like dust?

[daniel_owen_uk]

You don't really "need" a workstand I have changed everything on my bike;

Forks, Cranks, Wheels, Derailleurs, Brakes etc. etc.

And have never used a workstand, don't get me wrong I would love one, but it's all possible without.

[littlegirlbunny]

p.s - Mud? What's mud? Is it like dust?

not funny

just cos you get it all lovely n dry n warm over there

*is jealous*

[Jarl]

You don't really "need" a workstand I have changed everything on my bike;

Forks, Cranks, Wheels, Derailleurs, Brakes etc. etc.

And have never used a workstand, don't get me wrong I would love one, but it's all possible without.

+1.

[BarçaBike]

After much deliberation and lots of finkin, I turned the bike upside down. Much cheaper that way.

Once again, thanks for the advice, got it working real horrorshow, the only thing is when the chain is on the smallest sprocket there is little or no tension in the cable. Should this matter or is it a case of if it works, it works?

One day, everything will work.

[Alpine_Skier_UK]

After much deliberation and lots of finkin, I turned the bike upside down. Much cheaper that way.

The cheapest solution is usually the best

Once again, thanks for the advice, got it working real horrorshow, the only thing is when the chain is on the smallest sprocket there is little or no tension in the cable. Should this matter or is it a case of if it works, it works?

A cable that has little or no tension on whilst the chain is in the smaller sprocket is fine. Well fixed

[BarçaBike]

Nice one

Cheers