Tried using a 6mm Allen key on a 5mm bolt and stripped the head clean off.

I was rushing to fix a creaky bottom bracket on a Trek Emonda last Friday and grabbed the wrong tool, so what's your go-to method for getting a rounded bolt out of a carbon frame without making it worse?

4 comments

4 Comments

jenny422mo ago

Grab a torx bit one size up and tap it into the stripped hole... the sharp edges usually bite enough to get it turning. Just go slow and use steady pressure so you don't crack the carbon. A little heat on the bolt can help too if there's thread locker.

white.keith2mo ago

Carbon fiber cracks if you look at it wrong. You're telling people to tap a torx bit into a stripped bolt on a carbon frame? I've seen a seatpost clamp split from less force than that. Heat on the bolt near carbon is a whole other level of risky.

the_sage2mo ago

People forget carbon can hide damage until it fails later. That torx trick might work now but cause a crack you don't see. You're basically trading one stripped bolt for a potential frame break.

kimdixon5d ago

Yeah, @jenny42 I've seen that torx trick go sideways on a carbon fork once. The bolt came out fine but there was a hairline crack by the dropout nobody caught until the next ride. It's one of those fixes that feels clever until you're buying a new frame.