Sven's obviously a huge Dugast fan, and has used them for cross like essentially every top pro does in Europe (even when they color the sidewalls green and label them Challenge...). He's using them them for his MTB excursions and his ultimate goal of getting to the 2008 Olympics for MTB for Belgie. But having MTB'd for almost 2 decades, and seen all kinds of courses, I just don't know how these tires and carbon hoops can take it. He and Frischi use these religiously for MTB, so the suppleness and lightness (way lighter than a tubeless casing/wheel set up) must be worth the risk. I personally don't think the cotton casings are as robust as I'd personally want them for carving on an MTB. I get it on the CX bike to the extent I am never looking back, but MTB's are another story. Even with this Dugie flattening, he still podiumed at this race....although 3rd to Fil-epo's 1st on the day.