Tubeless design really makes a difference when it comes to mounting-easy to center and the tire runs true. This tire will hold its air for a week. The tread isn't the fastest, but provides sure footing in most conditions. The casing is a bit stiffer compared to something like a Challenge tubular, but you can run the Clement at sub 30psi without fear of pinch flats to get a supple feel. Oh, and no need to Aquaseal the sidewalls!
This tire is better than the Grifo Challenge in most ways.
-The construction is beefier, particularly the sidewalls, though the MXP is a little lighter than the Challenge.
-The shoulder tread is a little grippier than the Grifo (my rear end does not slide out as much, though the Grifo does slide predictably).
-The construction is uniform (it's not handmade). This made it easier to glue on because the sidewalls are a consistent width, additionally, the circumference was much less lumpy than the Grifo.
The Grifo is noticably more supple, however. This means that I run the Clement at a lower pressure to get the same ground profile, but it still seems a little stiffer than the Grifo.
Because a tubular issue can end my race or at least kill my chance at a decent call up next week, I'll put the durability of the Clement over the suppleness of the Grifo, and now only ride Clement tires (MXP and the PDX).
I love the Clement line of tubulars. The MXPs are fast and hook up well. Best of all, the glue up well, are super straight and you never need to worry about repairing a tube. I run mine with some Stan's.
Clement MXP tubulars have helped me bring home 3 wins and 3 podiums during my first year as a cat 2 cyclocross racer. These tires hug corners at high speed and have very little rolling resistance at high speed in the fast sections. Great tires !!