Greg Balzerwrote a review of Mavic Ksyrium Pro UST Wheel on March 15, 2019
Familiarity: I've put it through the wringer
I purchased these wheels to replace a pair of 2012 Mavic Ksyrium Elite clinchers installed on my 2008 Cannondale Synapse SL3. This is my daily commuter, about 10 miles daily, and I wanted something softer riding my previous Specialized Armadillo tires, yet also as puncture-proof. Long story short - the bike feels wonderful - the wheels and included UST tires are roughly 1 pound lighter - and the ride with the 25c wide tires is pretty plush. Longevity is a mixed bag - however - and that is why I knocked off one star. The second week I rode on these tires I flatted the rear with a slice so wide that it wouldn't seal. I replaced the tire with an identical one from Mavic, and after five weeks of riding, I have yet to flat again.
The wheels are light, yet strong. The feel at least as reliable as my previous set - if not even more so. The spokes are beefy, I'm not sensing any flex in riding, and they look great.
Mavic has nailed tubeless - the tires fit the rims like a glove. I was able to mount them without any tools, and the tires seated instantly with a common floor pump. The sealant is a bit of a PITA, but it wasn't awful to take care of - and the extra insurance against flats is probably worth it. As others have noted - it's not uncommon to lose 5-10 psi overnight - there may be tricks to get the tires to seal better - but generally I inflate to 80 psi in the morning and then reinflate two days later.
If the tires were a bit more indestructible this would be a 5-star review. I imagine that over time Mavic/Hutchinson will tweak the tires a bit more to improve reliability - but overall I am very satisfied with the tire and wheel package for commuting and weekend rides.