Bicycle Mechanics - Cross-theaded rear derailleur hole in frame

Being an idiot, I cross-threaded while reinstalling my rear derailleur. Now what do I do?





"There's no problem so small that it cannot be made worse by an idiot with small tools." -- me

Is it a replaceble hanger? If so no problem. If not you'll want to take that in and have a helicoil put in.

Is it a replaceble hanger? If so no problem. If not you'll want to take that in and have a helicoil put in.

Not sure what you mean by "replaceable hanger." The damage is the theaded hole in the bike's frame.

Then helocoil it is! Your LBS should have the gear to do that. If you feel the need to do this yourself, find out what size the screw is and then get a Helicoil kit at an industrial supply house like J&L Industrial or McMaster-Carr. Kits are not cheap. (An M10 kit would run you $74.82 at J&L.)

I reccommend having someone else do it for you.

Not sure what you mean by "replaceable hanger." .Term defined Here (http://www.sheldonbrown.com/harris/hangers/)

If you didn't thrash more than the first few threads, it couldn't hurt to try this: take the wheel out of the frame and screw the derailer bolt in from the the inside. Remove it and blow the metal bits out of the threads. Sometimes this cleans the threads enough to successfully install the derailer from the proper side.

It's worked several times for me. If it doesn't for you, you can still take your frame to a shop after that..

Good luck
Y.

I did this once. I was traveling a lot and breaking down and re-assembling the bike a lot and cross-threaded the rear derailer hanger threads. My bike does not have a replaceable hanger so I got myself a heli-coil kit and inserted some new threads - I think threads are 10x1mm. The kit wasn't a lot - maybe $20?

Being an idiot, I cross-threaded while reinstalling my rear derailleur. Now what do I do?





"There's no problem so small that it cannot be made worse by an idiot with small tools." -- me

My first shot would be to run a tap through the derailleur hanger from the inside. If the crossthreading isn't real bad, that'll fix it. If that doesn't work, check with your LBS for an item called a "Drop out saver." It's a threaded insert that has a flat hex head that goes on the inside next to the wheel. Should only cost about $10.00 - $12.00 and doesn't require any special tools to install.

Whenever somebody makes the effort to manufacture and market a product like "drop out savers," you can be sure that you're not the first guy who has ever had this problem.

You can also get a Frame Saver, which is basically a threaded sleeve that fits inside the hole in the hanger. You will have to drill out the hole a bit but then the sleeve just pops in and the derailleur screws into that. Kind of a similar concept to a Helicoil.