Riding along at a good clip, and a rider comes from the left. I punch it to get ahead of him, but he is stronger and gives me the look as he pulls ahead, but doesn't turn and sails off the embankment at the edge of the road, airborne, dropping 50 or 100' to a grassy area below. I slow & stop to see if he's OK, & he is pushing the bike along- the tires have come off.