UTQG tyre ratings: what the grades measure

The controlling grading rule is 49 CFR §575.104. It covers new pneumatic passenger-car tyres with listed exceptions, including deep-tread winter snow tyres, temporary spares, tyres for rims of 12 inches or less and qualifying limited-production tyres. A missing grade does not by itself prove an illegal or poor tyre.

Source: eCFR — §575.104(a)–(c)

Treadwear

Treadwear is relative wear on a specified controlled course. The regulatory example compares grade 150 with 100 as 1.5 times the course performance. Actual service may differ substantially with driving, maintenance, roads and climate; the ratio is not a promised road-mileage multiplier.

Source: eCFR — §575.104: Figure 2, Part II

Traction

Traction grades AA, A, B, C rank straight-ahead wet braking on specified asphalt and concrete test surfaces. They do not grade acceleration, cornering, hydroplaning or peak traction. C may indicate poor traction; do not translate a grade into a stopping distance.

Source: eCFR — §575.104: Figure 2, Part II

Temperature

Temperature grades A, B, C concern heat generation and dissipation on an indoor test wheel. C is the stated minimum performance level, not an automatic failed grade. The grading assumes proper inflation and no overload; it is not a speed symbol or a guarantee against heat damage.

Source: eCFR — §575.104: Figure 2, Part II

For a label such as 300 AA A, read three separate results. Check the exact product and approved fitment first, then compare relevant test evidence. Do not infer a softer compound, better dry grip, a fixed lifespan or a whole-brand ranking from treadwear.