Originally Posted by Maelstrom
Phantom
But agree, with the right ht, it can be very strong. I would be far more concerned tacoing a 32 hole wheel before breaking a frame.
I've seen cracked BB shells and cracks around the headtube from hard hits, usually. You're more likely to pop some spokes or shear a BB spindle than drop the BB out, but it's still possible, especially on aluminum frames, which most XC bikes seem to be.