Bicycle Mechanics - An interesting new failure - derailer hanger failure mid ride

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krobinson103
06-15-12, 03:16 AM
I got to walk home this morning - the derailer hanger threads must have worn out. Good thing the failure was close to home or things might have been bad. I think I need to add a derailer hanger to my spare parts in the saddle bag. The bike always finds a weak point somewhere.

KevinF
06-15-12, 04:02 AM
The derailleur hanger threads? What happened? Did the derailleur just fall off the bike?
krobinson103
06-15-12, 04:10 AM
Must have worked loose. Then rattled around a while. Thinking about 7 and 8 have been jumpy on gravel or really uneven surfacesfor a week or so. So the thread wore out, I compensated with the barrel adjuster and today it just decided to fall off. Wasn't moving fast or it could have be very unpleasant. Got a new one that was 99% right and dremeled it to make it fit. Only needed a few mm here and there. Put the whole system back together, tightened everything as far as is safe and it rides nicely now. Still, given its a small and light part carrying an extra can't hurt.

dsbrantjr
06-15-12, 05:16 AM
A little thread locker like blue Loctite might be a wise precaution since the first one worked itself loose. Proper torque is also necessary; properly-torqued fasteners typically don't come loose. A spare hanger (and bolt) is always a nice item to have around, I always carry one. A pre-ride check might have revealed the loose hanger.