Well, that was a first. Both tyres instaflatted on a particularly flinty descent this morning. Not going particularly fast fortunately. Really odd. Both tyres Gatorskins, front brand new with new tube, but rear has been on for ages. Inflated to 100psi (25mm tyres). Need to have a good look at the tubes. I'm guessing just bad luck - jinked sideways to avoid a pothole and down they went.
Top tip - always check both tyres are up before riding off