Disagreement between UTQG and independent tire traction ratings?

General Discussion
2

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.