When Derailleurs Attack

rank_amateur

I've come across a few threads now where people are 'just riding along' when all of a sudden their rear mech goes rogue - damaging dropouts, spokes, paintwork and even breaking chainstays. What the hell actually happens? So I can make sure it doesn't happen to me. As someone who's broken two chains in the last six months (actually the same one twice but at different links) I must be a prime candidate. :shock:

flasher

Google 'dork disc'.

grenw

Missus on her Mtb has had a chain almost come apart and it jammed in the rear derailleur cage. Snapped the mech hanger in half, luckily no other damage. A few miles of single speeding home was the punishment

sungod

stuff fails

maintenance and periodic inspection may reduce the likelihood that you'll be on the the wrong end of a failure

fwiw a few months back i was checking the rear mech due to poor shifting that i couldn't fix with the adjuster and noticed it moved waaaaay too easily on the hanger, turned out the hanger had cracked at one of the mounting screws

moral: if something doesn't seem right/as good as it used to be, find out why

jermas

Make sure the rear derailleur limit screw is set so that the mech can't hit the spokes. Pull the cable (under the down tube) to check.

keezx

Guess its just bad Karma.
I never wrecked a derailleur in 45 years.

rank_amateur

Cheers for the replies. I tend to keep my bikes pretty well maintained and clean so hopefully that will minimise the chances. Likewise I've been cycling for at least 35 years and never had it happen to me yet. Although, does that mean it's about time?

itboffin

i've had one snap inwards taking out several spokes bending the chain and destroying the mech in the process but then it was a CX bike riding off road and hit a rock so not really much i could have done apart from missing the rock.

long slow walk home