I've been using doubled up tyres on the back wheel of my winter bike for a while now- I always have the most worn tyre on the back, but sadly Gatorskins aren't so p******e proof when they wear thin. So I pop a worn out race tyre inside (a GP 4000 with the bead cut off) to stop the P******es happening. And it works!

Last Sunday I was wondering why there was a repetitive bumping feeling, discovered this when I got home...