I was riding on the verge of a 4-lane highway, when I heard a regular thump-thump-thump. Got off the bike, the tyres were okay, pushed the bike and again felt the thump-thump-thump. Had a closer look at the back tyre and there was a 6" piece of rod that looked very much like a part of a bicycle spoke (without the curved bit though), sticking through the wall of the tyre. The rod had completely penetrated the tyre and was sticking out 2" on either side. Same direction as the handlebars, just to make things clear.
I didn't have a flat at this stage, but when I pulled it out I did. I should have kept the rod, but I tossed it away in disgust. I don't really know what it was, but let's say it was part of a spoke. It was not one of my spokes. None of mine were broken.
What could have caused this spoke to penetrate my tyre? The reason I am concerned is that if it penetrated my tyre, it could just as easily have penetrated my leg.
I have some theories:
1. Self caused. I ran over the spoke and somehow it was catapulted into my back tyre.
2. A car ran over the spoke and "pinched" it under a wheel, giving it enough horizontal velocity to penetrate my tyre.
3. Someone had set up a booby trap by the side of the road.
4. Some local lout had invented a gun to shoot bicycle spokes and aimed it at my tyre.
I have mentioned this puncture to some cycling friends. None could come up with a believable explanation. One of them was so interested that he rang the Police and asked if they were aware of any mechanism that could fire spokes. They said no. Then we went to look for it, but no luck.
Has anyone else had a puncture like this?