I wondered what was causing the loud ticking noise ...6 inch piece of rebar will do it.....

 

Had same years ago in my Mini, strangest sound. It was a long M8 bolt sticking out of the sidewall and hitting the inner wheel arch at the back lol

 

I've found a razor blade in one rear tyre before, only found out due to seeing the odd spark from it.

 

Had an 8 inch long screwdriver minus the handle go right through a tyre! Same thing with me wondered what the strange clickity click noise was, pulled over and all that was visible looked like a nail. When the tyre was taken off was really shocked!!!