Originally Posted by
WhyFi
Now that understand that the bike is upside-down, and the crack on the seat stay is buckling in the direction of wheel rotation... yeah, I'd bet dollars to donuts that it picked up a stick in the spokes.
Originally Posted by
himespau
I was very confused by the picture as well. Would a stick be strong enough to do that damage without hurting the spokes?
I like the stick or road debris hypothesis, but @
himespau has a good point that the stick would tend to cause more damage other than the point damage spot. Both seatstays? For a partial crack, one might see impact damage at the back, and opening at the front, so several different views of the crack would help.
I might expect centrifugal force to push the stick out to the rim. But the physics of it may be more complicated with the rim largely stationary with respect to the street.
And since it isn't completely sheered, either it stopped the rider cold, or whatever it was either broke, or fell out of the spokes.