UTQG: TREADWEAR 400 TRACTION A TEMPERATURE A
US Uniform Tire Quality Grades, each from a government test: treadwear compares wear with a reference tyre on a test course (400 = four times the 100 reference); traction grades straight-line wet braking (AA best, C lowest); temperature grades resistance to heat build-up (A best; C is the legal minimum).
What to do with it
Use the grades to compare tyres, and treat treadwear as relative: the regulation’s own explanation says relative performance “depends upon the actual conditions of their use” and may depart significantly from the norm with driving habits, service practices, roads and climate.
- What it looks like
- On US passenger-car tyres, near the shoulder: TREADWEAR followed by a number (a multiple of 20), TRACTION AA, A, B or C, and TEMPERATURE A, B or C.
- Set by
- 49 CFR 575.104, § 575.104(c)(1), (d)(2)(i)–(iii) and the explanation of DOT quality grades
In detail
- Treadwear, from the regulation’s explanation: “a tire graded 150 would wear one and one-half (1½) times as well on the government course as a tire graded 100.”
- Traction: “the tire’s ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete.” It excludes cornering, acceleration and aquaplaning.
- Temperature: C “corresponds to a level of performance which all passenger car tires must meet” under Standard No. 109; B and A are higher.
- Not graded: deep tread winter-type snow tyres, space-saver or temporary spares, tyres for rims of 12 inches or less, and limited-production tyres.
What it does not mean
The treadwear number is not miles or kilometres, and traction AA says nothing about snow, ice or cornering grip. These are US grades, separate from the EU tyre label.
Markings that go with it
Sources
Each document was fetched and read on the date shown; the clause is the one that sets this marking.
- US National Highway Traffic Safety Administration, on eCFR: 49 CFR 575.104 — Uniform tire quality grading standards — § 575.104(c)(1), (d)(2)(i)–(iii) and the explanation of DOT quality grades: Treadwear is “a number of two or three digits … expressed as a percentage of the NHTSA nominal treadwear value … in multiples of 20”; traction “AA, A, B, or C”; temperature grades “A (the highest), B, and C”. Checked 2026-09-28.