I've had Blumels fitted to my bikes for about 30 years. They will break, but you do have to directly abuse them - the road has never done that on it's own. I broke one pair after ~15 years. I jammed a lot of fairly solid mud in it if I remember rightly, and distorted it (riding off-road with very tight clearance on a 28mm tyre - all my own work).Thank you everyone. You've all been very helpful. It looks like sks are the brand to go with. I am running 35mm tyres so should be okay with any of the suggested models. There are some reports online of the Bluemels cracking due to vibrations caused by the not so smooth British roads. Have any of you guys experienced this?