bubbajoelouie

Hello all. Last weekend I suffered my first component failure while out on a group ride. The rear derailleur hanger snapped in half, sending the derailleur into the spokes, twisting the chain and stopping me dead in my tracks. My LBS did a great job of assessing the damage and in a few days, I was back on the road. My repair guy said that the hanger snapped because it had been bent and that the stress during regular usage was responsible for the eventual failure. During this conversation, I wasn't able to recall an incident that started the process resulting in the damage. My bike, a Trek Domane 4.3, is only 9 months old and I just wasn't connecting the dots. Thinking back, I now remember 2 incidences of zero MPH falls due to being unable to clip out on the right side. I remember my knee and hand impacting but not the rear derailleur coming into contact with the ground in order to bend the hanger. I'm not disputing the LBS and their opinion, just wondering if anyone else has had something similar to this happen and how it might have come about. Thanks for taking the time to read my lengthy post.

bt

operator error

tagaproject6

I see a lot of derailleur hangers that had been moved closer to the spokes. The owners usually put their bikes in their vehicles with the drive side down. The first sign are usually shifting issues.

Looigi

More likely the RD hit the spokes then broke the hanger rather than vice versa.

CliffordK

Were you on a hill, or otherwise in your lowest gear on the rear when this happened?

If you ever hear your derailleur pinging on the spokes, you must stop and investigate.

TrojanHorse

Yep

milkbaby

^This +1000

When you lay the bike down on the drive side, you can bend the derailleur hanger inward towards the spokes. Everything is fine until you shift into the big cog and the derailleur then proceeds to get caught into the spokes. The hanger is built to break off in that instance because it's cheaper to replace than a broken drop out or chainstay.