So, for my last set of wheels I tried a pair of (what I was told) were strong XC rims. Mavic 717s. So, I had a look today at my tire as it suddenly seemed like it needed to be trued. Nice big failure around some of the spoke holes and the metal pulled away from the rim. For some reason the LBS wants a week to build me a new wheel so this time around I will be trying downhill MTB rims which again, I am told should be very strong. Mavic EX721s. Lets see if I get more then 3000k out of these ones.