I am considering the Pirelli Scorpion Weatheractive and Michelin CrossClimate2. I noticed that the CrossClimates have a UTQG traction rating of B, whereas the Scorpion has an A, but in looking at some of the independent tests, the Crossclimate traction is as good or better than the Scorpions. Why might this be? Should I trust one over the other?
Actually, the test results in your reference and the UTQG traction rating say the same thing. The UTQG rating measures the coefficient of friction on a wet surface. Basically, a shorter stopping time is equivalent to a UTQG A rating vs a B rating. In the wet handling test in your reference, the Pirellis stopped faster than the Michelins.
You do know that the “Traction” rating is based on braking on a wet surface.
Both sources say the Pirelli say is a better tire.