I needed to set up my rear derailleur from scratch yesterday and thought up a nice simple mechanism for doing it that I’ve not seen described before. This is for a ‘normal’, not reverse-pull derailleur, where increased gear cable tension makes it change down.
- Put the bike in middle ring at the front, set the rear shifter to top gear.
- Adjust the limit screws.
I find this is especially easy if you disconnect the gear cable completely – it prevents cable issues interfering and means you don’t need to fiddle with the shifter.
- Adjust the bottom limit screw so that the bike pedals smoothly in top gear with no clicking or rubbing.
- Push the derailleur with your fingers so that it shifts into bottom gear and adjust the top limit screw so that the bike pedals smoothly in bottom gear with no clicking or rubbing and without falling into the spokes.
- Screw in the barrel adjuster on the derailleur (and the shifter) as far as it will go.
- Pull the gear cable tight with your fingers (you don’t need much tension, just take up the slack) and tighten the retaining bolt.
- On the shifter, change down ONE gear (e.g. 8th if you have a 9-speed cassette).
- While turning the pedals, turn the barrel adjuster until it shifts into the selected gear.
- Adjust so it’s not rubbing and that the top jockey wheel aligns nicely.
- Check that it changes into all the gears smoothly when changing both up and down.
- Job done!
This whole procedure can be done in a couple of minutes. You may need to fine-tune the barrel adjuster slightly in some lower gears, but this procedure will get you to the right ballpark with minimal effort. It’s much easier if you have a workshop stand or similar means of holding the back wheel off the ground.