Gowen,
i was thinking about this..
and as far as durabilty..
guys that truly punish their machines and frames
are the distance jumpers ,because despite the landings looking groomed and matched to thier landing/ approach angle, they are still taking imact that most guys never dream of in any SX/MX or off-road situation.
example: Trigger Gumms 274 foot jump a couple of years ago
to smash the old distance record and set the new world record
looked as smooth as silk., (catch it on youtube .brisbane australia crusty..)
and perfectly executed. plus he acted like all was well.
few know that he compression fractured his back in the landing
anyway that was an 05 CR500AF and h estil rdes and jumps oitt othis day.
(he bought anouther 08 recently,,but his 05 is fine and running well,,he just wants to put it up as a trophy)
anyway the long distance guys riding and jumping these is a long list.. and thier AF bikes are stone reliable.
they regularly practice at 250 feet over and over ,,so they diffinantly put some hard use into these bikes.
Robbie Maddison (CR500AF) current world record holder at near 350' ?
(same bike he jumed to 300 feet on new years eve)
Robbie Knievel (CR500AF)
Trigger Gumm (CR500AF)
Ryan Capes (KX500AF)
Brain Deegan (CR500AF)
Mike Metzger (CR500AF)
the list is longer,
but my point is i doubt any of us mere mortals have to worry, the bikes are stronger and more durable than the original OEM steel frames.