Originally Posted by
rhenning
You do not really need one unless you drop your bike or crash a lot. I am 73 years old and have yet to need one. Roger
Ridden by a child. You'll see from the photos I've attached that the derailleur had took a hard hit from the scuff marks and the photo looking down at the hanger and mech, it's possible to see that there is a substantial bend in the hanger. Also, there is excessive play in the mech's moving parts. That's not going to to be re-indexed. I hope he looks after his new cycle better than he has looked after his old one. Yes. Lots of rust on the old cycle. :-(

In the above picture, the cog the chain is sat on is the highest gear that can be selected. That's now much the mech and hanger is damaged and the reason I'm after fitting a derailleur guard on the new bike, but the design of that part of the frame is giving me a headache selecting a guard that will correctly fit.