Cycling UK Forum

So I tried to follow some guides online to service my rear derailleur. It's a Shimano XT 9 speed on my Surly Disc Trucker. It's a fairly new bike, but the gears began to start slipping and clicking after about 300 miles, so it obviously needed a tune up, however the LBS i got it from has closed for 4 weeks due to being involved in some kind of charity ride, so figured I've give it a go myself.

Mistake! I've buggered up the indexing big time. Now it will barely go from gear to gear without some kind of horrendous noise. I did everything right, I think.

I've screwed and unscrewed the L and H, and B Tension screws so much I lost track of where I started.

What's the prognosis guys? Do I give in and take it into another shop, or is there a good guide online that I can use that will essentially show me how to start from scratch??

This may help. http://sheldonbrown.com/derailer-adjustment.html

Unfortunately you've made the common mistake (we've all done it at some time) of changing too much at once But I guess you've probably already come to that conclusion.
I suspect what caused the problem in the first place was a case of new cable stretch, but now you need to get things back as they should be. I'll resist the urge to try and explain how I'd do it (which may or may not be the same as others) other than saying I'd suggest (as you've moved them anyway), that you screw the H & L screws in a bit just in case you've undone them - you don't want to change gear and damage the wheel or the frame by overshooting the sprockets! That said, I'm confident there will be some (better than my) guidance on the net. Try to familiarise yourself with what each of the adjustments does, and it will become something you'll be able to easily do yourself in the future. Once you can do it it's (relatively) easy - like many tasks (but darned difficult if you can't)

fastpedaller wrote:Unfortunately you've made the common mistake (we've all done it at some time) of changing too much at once But I guess you've probably already come to that conclusion.
I suspect what caused the problem in the first place was a case of new cable stretch, but now you need to get things back as they should be. I'll resist the urge to try and explain how I'd do it (which may or may not be the same as others) other than saying I'd suggest (as you've moved them anyway), that you screw the H & L screws in a bit just in case you've undone them - you don't want to change gear and damage the wheel or the frame by overshooting the sprockets! That said, I'm confident there will be some (better than my) guidance on the net. Try to familiarise yourself with what each of the adjustments does, and it will become something you'll be able to easily do yourself in the future. Once you can do it it's (relatively) easy - like many tasks (but darned difficult if you can't)

I definitely did too much at once. I tried to start off with small adjustments then just went a bit crazy. I tend to do that

It's actually unridable now though

I'm scared of touching it again.

You didn't need to touch the screws (probably)....I expect all you needed to do was to adjust the cable barrel adjuster to take up the slack a bit.
Got a maintenance stand?... put it on middle ring of 3 at the front.
Put it on top gear (smallest) at the back....there should now be a bit of slack in the cable.
To check the "H" setting, see if you can pull the mech. to shift the chain past top sprocket to hit the dropout....that is the travel that "H" limits.
Adjust the barrel adjuster so it changes doiwn one sprocket for each click....when you get to the biggest sprocket (first) check that you can't push the mech. to get the chain in the spokes....carefully!.... thats what screw "L" adjusts.
then check it changes with equal enthusiasm both up and down, 1 gear for 1 click, each way.......set this with the barrel adjuster

Simples?

.

When it's a lost cause it is better to unship the cable and start from scratch. Never do up a cable clamp bolt too tight because that can damage the cable.

The cable barrel adjuster only needs a 1/4 turn a time. Sometimes just a single quarter turn will get poor indexing sorted. And usually that is a 1/4 anti-clockwise turn owing to cable stretch.

Valbrona wrote:When it's a lost cause it is better to unship the cable and start from scratch. Never do up a cable clamp bolt too tight because that can damage the cable.

The cable barrel adjuster only needs a 1/4 turn a time. Sometimes just a single quarter turn will get poor indexing sorted. And usually that is a 1/4 anti-clockwise turn owing to cable stretch.

You don't need to touch the cable clamp.....as long as there is a bit of slack in the cable in top (or as long as there can be a bit of slack if you back the barrel adjuster off a bit), and as long as the barrel adjuster(s) have some travel left.

1/4 turn is the smallest adjustment you can make. If its almost perfect, then its all the adjustment you need to make. If, however, he has messed about with it to such an extent that the cable is so slack that the first click of the lever doesn't shift the chain off top to next to top sprocket, then 1/4 turn really won't help. ....same if the cable is too tight and it won't shift into top.

In my experience the cables on a new bike - or rather any new set of cables any time - will slacken a wee bit after the first couple of hundred k. When I moved from 9 to 10-speed it was great at first then started jumping all over the place. I bitterly regretted the move until I screwed up the courage to take up the slack myself. Until then I thought they'd be far too sensitive (wee thin chain, tight spacing on cranks & cassette) but now they're just ordinary.

Take it slowly and logically and your Surly will smile again soon.