I have a set of Enve 45 clinchers mounted to CK R 45 hubs that I use as my everyday riders. Super durable ... ton of miles on them ... true as the day they arrived from Wheelbuilder. I live in a hilly area with some short to moderate but steep descents and have never had a problem with the braking surfaces. If I was ever to use them in more of a mountaneous area I would be sure to use the brakepads supplied by Enve which will limit the amount of heat generated on long descents especially if you pulse your brakes rather than ride them on long down hills. I also use a set of Enve rims on my 29er for everyday use. Bottom line is they are very tough rims that stand up well to everyday use.