Bit of a scare this morning on the way too work. I have been using my 2010 boardman mtb pro to commute to work on since my commuter bike (and I) got wiped out by a car. To make things a little easier I had fitted shwalbe kojak tyres and had been massivly impressed. They cornered well and the low rolling resistance was a dream. I have had them for about 4 weeks so they were in good nick. This morning I was belting down the hill on the way to work when without warning the tyre jumped the rim, the tube wrapped around the cassette and locked up the back wheel (i was doing 30 when it happened so it was quite a shock) I had checked the pressures before setting off and they were good and there was on evidence of a puncture in the tube (apart from the ones made by the cassette). Any ideas? The rim looks to be a mess do I write to the manufacturer?