Question about using a zip tie to set up a new derailleur

Had a customer bring in a bike with a new 12-speed derailleur that just wouldn't shift right. The hanger looked straight, but the indexing was off. On a hunch, I used a zip tie to pull the cable tight against the frame before clamping it down at the anchor bolt. It worked perfectly, first try. Is this a legit trick for getting cable tension right, or did I just get lucky?

3 comments

3 Comments

logan2051mo ago

Got a question about your zip tie trick. Did you pull the cable tight with the shifter already clicked into the highest gear, like the smallest cog, before you clamped it? That's the standard starting point for cable tension, and if you did that, the zip tie just helped you hold it there without it slipping. If you didn't, then you might have just accidentally set the right tension by feel, which is lucky but not repeatable. The real test is if you can do it again on the next bike with the same good result.

the_xena1mo ago

You're overcomplicating a simple hack.

alex_nguyen23d ago

I get what you're saying but I actually think that's backwards from how it usually works. On most cable systems you want to clamp the cable with the shifter in the highest gear, then pull it snug but not tight enough to yank the derailleur into a higher gear. The zip tie trick is useful because it holds the cable in place at the clamp while you fine tune the tension at the barrel adjuster. If you just clamp and go you're relying on the cable friction staying put, which it never does on a new cable. So the zip tie basically gives you a third hand to hold the cable steady while you dial in the tension correctly. That's why it works even if you don't hit perfect tension on the first try.