Argh! A minor shop annoyance

[OakLeaf]

Okay. Sounds like the cable's just too loose, and chainline is contributing to the rub.

Still, it shouldn't be rubbing at all on the small ring (at least not when you're not cross-chaining), so your low limiter screw probably does need a little tweak.

Here's a video.

Look at your derailleur to make sure which is the high limit screw and which is low. They're not always the same as the one in the video, but they're normally marked H and L. If not, you can go to Shimano's website for the instructions for your particular derailleur, or just see which one moves the derailleur when you take all tension off the cable and mark that one as your Low limit screw. (If you tried the High limit screw first, count turns of your screwdriver - the Phillips head makes it easy to see a quarter or half turn - and make sure to put it back where you found it.)

If you have a barrel adjuster on the cable near the handlebars, then unless it's already at its limit, you won't need to loosen and re-position the cable in its clamp. Unscrew the adjuster (turn it in the direction that makes the housing longer - on my bike, it's away from me as I sit on the bike. You can watch the cable at the derailleur end and see what's going on as you turn the adjuster each way, if you're not sure) until there's no slack in the cable when it's on the smallest chainring.

If you don't have a barrel adjuster - or if it's already at its limit and you need to reposition the cable in its clamp - then pay attention to how it's routed and how the clamp sits before you loosen the clamp. On some derailleurs, unlike the one in the video that stays neat, the cable will just fly off, and/or you'll accidentally loosen the clamp a little too much and it comes off. So you want to know before you start how it all goes back together. Do make sure that you screw the barrel adjuster all the way back in before you reposition the cable (the guy in the video overlooks that at first and then goes back to it).

The guy in the video just pulls the cable taut using his fingers before tightening the clamp, but I find a pair of pliers handy here. Just to get a better grip on the cable, try not to crimp it.



Derailleur adjustments are so simple, and need to be done fairly regularly - sometimes on the road - so it's good to know how to do it yourself.

Plus, I've always found that learning to fix something of my own just feels tremendously empowering.