Actually, it was a front, but we weren't travelling awfully fast at the time. He stopped immediately and in a straight line - no panic or anything - and waited for me to inspect. We thought it might have been an old tyre giving up, but I was astonished to see the remodelling. It hasn't put him off. In fact, now we've looked out spares, he's happy with some fancier wheels and some Bontrager tyres which were to be spares for Butterfly's carbon fibre loveliness. I need to sort out a cassette to fit and some new brake blocks now.
