Killed a customer's derailleur and learned my lesson about torque wrenches

I was working on a customer's Specialized Tarmac in my garage last Thursday and decided I didn't need to grab my torque wrench for the derailleur hanger bolt. I just went by feel like I always do. Snapped the bolt clean off inside the frame. Had to drill it out and tap new threads, which took me almost 2 hours and cost me a new hanger and a lot of embarrassment. Customer was cool about it but I felt like an idiot. Anyone else had a moment where skipping the torque wrench bit you hard?

2 comments

2 Comments

umaf441mo ago

You really think so? I see it different. A skilled mechanic should be able to tighten a derailleur hanger bolt by feel nine times out of ten. That bolt is small and easy to overdo, sure, but that's exactly why you pay attention. If you're snapping bolts on routine stuff like that, maybe the issue isn't the tool, it's how hard you're cranking.

the_jenny1mo ago

Heard that a lot but how many bolts have you actually snapped before you figured out the right feel?