Very, very heavy, thick rubber, but one pinch flatted so nothing sophisticated in this material - ok, it was sharp slate and I was really hooning, but I've really not had many pinch flats at all in my lifetime of riding like an idiot over sharp rocks... worse was the other had a leaky valve that eventually gave up. Going to try Maxxis next time. These are not deal breakers but I do a lot more miles on other tubes without any problems at all.

Reply from Charlie: I have used these for years and they have been fine. A pinch flat is a pinch flat, and not really a fault with the tube. and these bikes go so damned fast that pinches are quite common. The valves can easily be tightened up, Stans make a wee tool. If you had let me know we would of replaced the valve. Maxxis and all the other brands are much the same: a tuber tube with a valve . I think you just got unlucky with the slate, and then a loose valve. Give us a call and I can talk you through the other options, inc the new tougher walled tyres from surly that will help prevent pinch flats. have fun... Charlie

Steve | Cheshire | November 2015