Looking for your guys input please, I know this is always the place to come for it. Long story short a friend of mine has a 2015 Scott 960 that has never given him much trouble, that is until he didn't secure it to his bike rack properly and it came off, although not at high speed and not long after he drove off. The damage didn't seem to be that much and was a broken spoke and some aesthetic damage which his LBS sorted out. However he started having trouble with gears jumping when under force up hills etc. It then ended up actually breaking the chain. The LBS tried a few times to get it right, changed the chain, rear derailleur and I'm not too sure what else. Gears still jumped and then they finally promised him it was sorted and that they straightened something which I understood to be the derailleur hanger. The chain snapped again and he resorted to buying a new bike. I decided to give the old one a test run this morning and lo and behold the chain snapped again after just 20km, Brand new chain. I'm not heavy on chains, this is the first one I've broken. I want to help him sort it out with the view of possibly buying it because it actually rode really well until the chain snapped, the gears did jump a handful of times when under force but was otherwise a pleasure. I don't want to go through a trial and error exercise unless I have to, What do you think should be checked and replaced first. It's an old groupset so I'm considering upgrading it to 1*11 eventually but if its not even a drivetrain problem but something else like bent, frame? Then it will be pointless. If anyone has any similar experience or advice it would be greatly appreciated.
