Hanger bolts Shearing..!!



whuppingboy

Member
Feb 22, 2010
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The other day i rode home from work as normal, hammering it all the way, racing everybody etc.
Got up the next day to service and clean my bike and as i took rear wheel off the deraileur fell off in my hand!!!
Both alan key bolts that held the hanger in place had sheared, one had disappeared totally the other head was there.
see pictures:-
P.S. Anyone else seen anything like this. I have had hangers snap before but not sheared bolts.
 
There has to be some other force at work here. There should be little strain on those bolts.
Over or under torqued? Dropped, bumped on that side? Poor quality bolts? Termites?

Not sure just how that one hooks up, I have a bike that those bolts just keep the RD
in place while the wheel is off, the axle nut actually holds the RD on.