My rear derailleur exploded on a casual ride last Sunday and it was bad

I was just cruising down a flat stretch near the river, not even pushing hard, when my rear derailleur just snapped right off the hanger. The whole thing got sucked into the spokes, tore up the chain, bent the hanger mount on the frame, and locked up the wheel so fast I almost went over the bars. I was maybe 6 miles from home with no tools except a multi-tool that couldn't fix a mangled drivetrain. Had to call my buddy to come pick me up in his truck, felt like a total idiot standing there on the side of the path. When I got it back to my bench, I found the hanger was cracked from a previous crash I forgot about, just waiting to fail. Anyone else ever had a derailleur get eaten by the rear wheel like that? What did you do to patch up the frame area where the hanger mounts?

2 comments

2 Comments

the_alice21d ago

Tbh I had almost the exact same thing happen to me two summers ago on my old Cannondale. I was bombing down a gravel descent near the reservoir when my derailleur just folded into the spokes out of nowhere. Same deal, the hanger was bent from a stupid curb hop weeks earlier that I totally ignored. The whole rear wheel locked up so fast I slid out and scraped up my elbow and hip pretty bad. For the frame mount, I actually had to take it to a shop cause the threads were stripped out and the hole was oval shaped. They ended up drilling it out and installing a threadless insert kit that cost me like 50 bucks but it worked perfectly. Honestly ever since that day I check my hanger alignment before every single ride now, learned that lesson the hard way.

joseph_murray821d agoMost Upvoted

50 bucks for a threadless insert kit sounds steep just because you ignored a curb hop for weeks. I've bent hangers before and just straightened them with a tool from Amazon for like 15 bucks, never had a frame mount get oval. Unless your Cannondale is made of butter, that seems like the shop took you for a ride more than the bike did.