A Failed Jump?

I took my sister's Fuji road bike to my local bike shop to get the brake cables replaced.  There's the possibility that it might need more than just that, but based on how much wear the drivetrain has, I doubt it was ridden very much at all.  The chainrings have minimal wear, the cassette's cogs' teeth are all nice and square, the chain is still good, the brake pads are fine.

While I was in the bike shop and staring at the clipless pedals and wireless cyclocomputers, a guy came in to pick up his bike.  The repairman brought it over, and I glanced at it.

It was a hardtail mountain bike complete with disc brakes and other accoutrements.  The thing that really struck me was the chain was all jacked up, the crank arms were all sorts of bent out, and the rear derailleur was in several pieces, dragging on the ground by its cable.  The repairman told the guy, "You definitely need a rear derailleur and bottom bracket, and probably a new chain."

I kind of felt like asking the repairman what happened, but I think I know.  The guy was riding his little mountain bike on a trail and figured he'd attempt to get airborn off a ramp, or do some sort of a jump.  He stood up on the pedals with the crank arms horizontal, and when he landed the rear tire either collapsed, crushing the rear derailleur, or he lost control and fell on his right side which would also crush the derailleur.  The bottom bracket spindle/axle probably couldn't handle the force of a 170lb guy accelerating towards the earth at 9.8m/s/s and then suddenly stopping, so I'm guessing it probably snapped.  I think BMX bikes are designed to do jumps and stuff like that. Mountain bikes are designed to take spills and everything, but probably not the type this guy had.

Anyway, I thought it was kind of cool seeing that much wreckage on a bike. Personally, when I go to pick my bike up tomorrow, I'm hoping to see a guy with his road bike in pieces arguing with the repairman, "Whaddya mean you can't fix this?! This cost me 4 grand!"