I picked up a rail road spike one fine day. Passenger side front tire nailed it. Car in front of me must have kicked it up just right. Clank clank clank clank clank!!!I had a mate find a 10mm combination spanner one day. Ran over it with the front tire on his MT09. It flicked up on just the right angle to penetrate his rear (tire) He now has the tire mounted on his "wall of shame".