FROM THE WORKSHOP...
Every time I try to index my gears they end up worse than when I started, is there a foolproof method to get it right?
Unless your rear mech is throwing the chain off, never, ever go near it with a screwdriver. The screwdriver is only useful for the limit screws and B-Screw and if your supplier set them properly, these will never need adjusting – doing so nearly always makes matters worse.
Ideally, you need a workstand to get the bike off the floor, the right way up. This is the single biggest tip for indexing. You can make minor adjustments on the fly, once you understand what you’re doing, but a workstand is really helpful at home. For the rear mech, all you need to adjust is the barrel adjuster on the cable. Don’t try and adjust all the gears in one go. Get the smallest two right, and the rest will follow (with very minor adjustment). You need to add or take away cable tension until the mech and chain run almost silently on the smallest sprocket. Add tension, and move the chain and rear mech toward the top of the cassette, by turning the barrel adjuster anticlockwise. Take it off by turning it clockwise to move the chain down the cassette until the chain is centred and running silently. Shift up and do the same for the second smallest sprocket. Don’t go crazy with the adjustments – only turn the adjuster half a turn at a time, and work out which way makes the chain run noisier and which makes it quieter. When you think you’re there, spin the pedals backwards – if the chain’s quiet running backwards too, it’s in a good position. Now all of your gears should be set.
DON’T GO CRAZY WITH THE ADJUSTMENTS ! ONLY TURN THE BARREL HALF A TURN AT A TIME