How to adjust index shifters

On Twitter, @ke7yxz asked: @cascadebicycle - can you give me tips and techniques to dial in an indexed shifter? I get skips and stalls when shifting after I adjust.

Yes we can! Our bike-savvy Major Taylor Project Coordinator, Silas Strickland, has the answers:

Before you begin, check two things:

1) Try pulling on an exposed stretch of the cable to make sure it is moving smoothly. Worn out or old cables and housing can cause terrible shifting and should be checked frequently.

2) Look at the derailleur cage from the back and make sure it is straight. Slightly bent derailleurs can go unnoticed and cause shifting to just never be quite right.

Checked? Let's proceed to the adjustments: 

1) You always want to start your adjustments with the derailleur in its most relaxed position. For most derailleurs, this means in the smallest cog (hardest gear).

2) Make sure your limit screw for the high gear (labeled with an "H") is adjusted so that the teeth of the top jockey wheel of the derailleur are directly in line with the teeth of the cog. And make sure it shifts swiftly from bigger cogs into the smallest. if not, loosen the limit screw a hair until the chain drops easily.

3) While pedaling, move the index shifter EXACTLY one index (one click). Do not help the derailleur shift by clicking ever-so-slightly more than one click so that it jumps quicker--proper adjustments will make it do that automatically.

a. If it does NOT shift into the next gear, tighten the cable (either with barrel adjusters if you have them, or by tightening the cable if you don't) until it jumps on its own in the next gear. Then, see 3) d.
b. If it does shift, but not smoothly, tighten or loosen the cable until the shift is quick and smooth. Then, see 3) d. 
c. If it does shift, but jumps more than one gear, loosen the cable until it only jumps one. Then, see 3) d.
d. When it does shift one gear smoothly and quickly, try shifting to either direction and then back into the original gear. If all is good, move on to the next gear.
e. Repeat steps a through d for every gear in the cassette until shifting is good between all the gears.

4) When you get to the biggest cog-- closest to the wheel spokes -- make sure your Low gear limit screw (labeled "L") is adjusted properly so that the chain go shift smoothly onto the biggest cog, but that the chain is not getting pulled into the spokes or rubbing between the jockey wheel and the cog.

5) If your shifting still skips, then I wish you the best of luck! Seriously though, you might have a more in-depth problem that needs individual attention and inspection, ideally at a bike shop you know and like. 

If you have any questions about bike maintenance, riding tips or bikes in general, email me at amrook@cascadebicycleclub.org or tweet us (@cascadebicycle) and I'll find an expert to answer your questions!

Previous posts:
​-Broken saddles and saddle maintenance

Pictures courtesy of Wikimedia Commons