UTQG ratings explained: treadwear, traction, temperature

In short. UTQG (Uniform Tire Quality Grading) is a US federal rule, 49 CFR 575.104, that makes tyre makers mould three grades on the sidewall of passenger car tyres: a treadwear number (in steps of 20, where 200 means the tyre wore twice as well as a 100 on a government test course in Texas), a traction grade (AA, A, B or C) for straight-line braking on wet asphalt and concrete, and a temperature grade (A, B or C) for resistance to heat on a laboratory drum. The maker grades its own tyres, so treadwear compares best between tyres of one brand, and none of the three grades is a mileage promise. Outside the US, in the countries we checked, the grades have no legal role: in the UK and the EU, the tyre label (fuel efficiency, wet grip, noise) does that job, and it contains no wear grade.

What the three grades say, in the rule's own words

The rule requires tyre makers and brand owners "to provide information indicating the relative performance of passenger car tires in the areas of treadwear, traction, and temperature resistance", with the stated purpose "to aid the consumer in making an informed choice". It dates from 1978 (43 FR 30549, 17 July 1978); the eCFR version history shows its latest substantive amendments on 8 June, 8 July and 14 July 2022 (eCFR, 49 CFR 575.104, read on 16 October 2026).

The explanation the maker must print (Figure 2, Part II) is precise. Treadwear: "a tire graded 150 would wear one and one-half (1½) times as well on the government course as a tire graded 100", and real wear "may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate". Traction: the grade "is based on straight-ahead braking traction tests, and does not include acceleration, cornering, hydroplaning, or peak traction characteristics". Temperature: "The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Safety Standard No. 109", and the grade holds for a tyre "properly inflated and not overloaded".

The grades sit on the sidewall "between the tire's maximum section width and shoulder", usually in the form "TREADWEAR 200 TRACTION AA TEMPERATURE A", the example the rule itself uses for owner's manuals. Replacement tyres also carry a paper label on the tread with the grades; tyres supplied as original equipment on a new car do not need that paper label. To place the grades among the other markings, see how to read a tyre size, load and speed index.

Which tyres have no UTQG grades

Paragraph (c) excludes:

• deep tread, winter-type snow tyres;
• space-saver and temporary-use spare tyres;
• tyres with a nominal rim diameter of 12 inches or less;
• "limited production" tyres: broadly, no more than 15,000 a year of one design and size in the US, a size not listed as the recommended size for more than 10,000 new vehicles the year before, and no more than 35,000 such tyres a year in total for the maker or brand owner;
• a new tyre line during its first six months of production, which need not have the grades moulded yet.

The rule covers tyres "for use on passenger cars". A tyre without grades is therefore not a defective tyre: it may be a winter tyre, a small-volume performance tyre, or a tyre outside the rule's scope.

Treadwear: how the number is made

The course. Paragraph (e) and Appendix A describe a public-road loop of about 400 miles around Goodfellow Air Force Base, San Angelo, Texas. A convoy of two or four vehicles runs together: one car on four course monitoring tyres (the ASTM F2493 reference tyre), the others on the candidate tyres, loaded to 85 % of the test load, with the alignment set to the midpoint of the car maker's range.

The run. Two laps (800 miles) of break-in, then 16 laps, about 6,400 miles. After every lap the tyres are rotated; every two laps the cars change places in the convoy; every four laps the whole set moves to the next car. Tread depth is measured to the nearest 0.001 inch, at six points in each groove.

The calculation. The maker turns the measured wear rate into a "projected mileage" to 62 mils of tread (1.57 mm, the 2/32 inch at which the treadwear indicators show, as Michelin describes them), corrects it with the reference tyre's wear on the same day, and computes the grade with the formula of (e)(2)(ix)(F): P = projected mileage × base course wear rate ÷ 304. The base rate is the average of NHTSA's last four quarterly runs of the reference tyre. The result is rounded "to the nearest lower 20-point increment".

A worked example, with invented numbers. This is our own arithmetic with the rule's formulas. A tyre measures 300 mils (7.62 mm) after break-in and 276 mils (7.01 mm) after 6,400 miles. Its wear rate is 1,000 × 24 ÷ 6,400 = 3.75 mils per 1,000 miles. With a course severity factor of 1, the projected mileage is 1,000 × (300 − 62) ÷ 3.75 + 800 = 64,267 miles. If the reference tyre's base rate were 2.0 mils per 1,000 miles, P = 64,267 × 2.0 ÷ 304 = 422.8, and the grade would be 420. At 1.9 mils, P = 401.7 and the grade 400. The same tyre, on a course that is a little less severe that quarter, loses a full step. We do not know the published base rates (they sit in NHTSA docket NHTSA-2001-9395, which we did not read), so this example shows the mechanism, not a real tyre.

Why treadwear compares best within one brand

Three reasons come from the text itself.

1. The maker grades its own tyres. Paragraph (d)(1)(i) says each tyre "shall be able to achieve the level of performance represented by each grade with which it is labeled". The grade is a floor the tyre must reach if put through the test, not a published measurement. Our reading is that nothing stops a maker from declaring a grade below its result, and one maker may do so more than another. We have no data on how much each one does.
2. The grade is rounded down, and it moves with the reference tyre's base rate, as the example shows.
3. The course is one climate and one road. The rule itself warns that real wear "may depart significantly" from the course.

Continental's Canadian page puts the consumer consequence plainly: "It is wrong to link treadwear grades with your projected tire mileage" (Continental Tire Canada). A treadwear of 600 is not 60,000 miles, and a 500 from one maker is not proof of longer life than a 440 from another. A mileage warranty, where the maker offers one, is a commitment; the grade is not. For how age and storage limit a tyre's life whatever its grade, see how long tyres last.

Traction: AA, A, B, C

Paragraph (f) uses a skid trailer towed at 40 mph on wet test pads at San Angelo, one asphalt and one concrete. One wheel is locked and the friction recorded between 0.5 and 1.5 seconds after lock-up, ten times per surface. The result is corrected against a standard reference tyre (ASTM E 501) measured within the same three hours.

The grade needs both surfaces. A locked wheel is not how a car with ABS stops, and the rule says the test excludes cornering and hydroplaning. Traction AA tells you about straight-line wet braking with the wheel locked, on a new tyre; it says nothing about snow, ice or a worn tread. Why a worn tyre stops longer in the wet is covered in stopping distances on wet roads, and the speed at which water lifts the tyre in hydroplaning and aquaplaning.

Temperature: A, B, C, and the speeds behind them

Paragraph (g) mounts the tyre on a rim, warms it to 95 °F (35 °C) for three hours, and presses it with 88 % of its maximum sidewall load against a steel drum 67.23 inches in diameter. It runs two hours at 250 rpm, cools, then runs 30 minutes at 375 rpm and 25 rpm more every 30 minutes, up to 575 rpm or failure. A tyre that does not complete the 500 rpm stage is graded C; completing 500 rpm allows B; completing 575 rpm allows A.

The rule gives rpm, not speed. We converted the drum's surface speed: circumference = π × 67.23 in = 5.365 m.

As it works out, the rpm divided by five gives the surface speed in miles per hour, to within a fraction of a mile per hour (our arithmetic; the rule does not say so). These are laboratory speeds under controlled pressure and load, not a permitted road speed: the speed symbol on the sidewall is the tyre's rated speed. The rule's own warning applies: "Excessive speed, underinflation, or excessive loading … can cause heat buildup and possible tire failure." Use the pressure on the car maker's placard; see tyre pressure: what it should be and when to check it.

What 7,485 graded tyre lines look like

We downloaded the tyre ratings that NHTSA publishes through its public API (api.nhtsa.gov/tires) on 16 October 2026: 7,485 records of brand, line, size range and grades. The data set has visible errors (one line appears under several unrelated brand names, a few grades are not valid values), and the records carry no date, so read the figures as an order of magnitude. Our counts:

Two lessons. First, in this data, wet grip and treadwear tend to trade off: the AA lines have a clearly lower median treadwear than the A lines. Second, the spread between brands (220 to 700 for the median) is wider than any plausible difference in rubber alone would suggest to us; it fits the self-grading reason above, though the data cannot prove it. When you compare, compare sizes too: one line can carry several treadwear grades.

NHTSA's April 2026 notice counts about 45 manufacturers grading for about 160 brand names, and estimates the programme's non-labour cost at about $35.1 million a year, of which $28.5 million is the printing of paper tread labels and $2.52 million treadwear testing (Federal Register, 8 April 2026).

Outside the United States: the rules by country

The EU text says why there is no wear grade: "a suitable testing method to measure tyre abrasion and mileage is not currently available" (recital 16), and Article 13(3) lets the Commission add abrasion and mileage "as soon as reliable, accurate and reproducible methods" exist (Regulation (EU) 2020/740). We read the text as published on legislation.gov.uk and did not check later EU acts on abrasion. On the label, wet grip comes from a wet grip index measured under UN Regulation No. 117: for car tyres, class A is an index of 1.55 or more (Annex I). The test and the scale differ from UTQG traction, so there is no conversion between a label class and a traction grade.

A tyre made for the US market carries its UTQG grades wherever it is sold. In Canada or the UK, they remain information from the US rule; the local law asks for something else, or for nothing.

Using the grades sensibly

• Start with the size, load index and speed symbol from the car maker's documents. The grades never replace them. Onyx Forged does not recommend a size or an offset; the tyre size calculator shows how two sizes compare in diameter, and tyre sizes for 19-inch wheels explains the trade-offs.
• Compare treadwear within one brand, one size range. Across brands, read it as a rough indication.
• Read traction as wet straight-line braking only. For winter, the snowflake symbol matters; see winter tyres in the UK.
• Real wear depends on you: pressure, alignment and rotation. See tyre rotation patterns. Whatever the grade, the legal minimum tread depth in your country decides when the tyre must go: see legal tread depth. A tyre with a bulge, a cut or cords showing should be checked by a tyre professional before you drive on it again.

Frequently asked questions

What does UTQG stand for?

Uniform Tire Quality Grading, a US rule (49 CFR 575.104) that requires treadwear, traction and temperature grades on passenger car tyres.

Is a treadwear rating of 500 good?

It is above the median of 420 we counted in NHTSA's data, so the maker graded it above most lines. It does not translate into miles, and it compares reliably only with tyres of the same brand.

How many miles is a treadwear of 400?

The rule gives no conversion. The grade is relative to a reference tyre on one Texas course, and Continental calls linking it to mileage "wrong". A mileage warranty, where offered, is the figure a maker commits to.

Is traction AA better than A?

Yes, for locked-wheel braking in a straight line on wet asphalt and concrete. It does not cover cornering, hydroplaning, snow or ice.

Does temperature A mean I can drive faster?

No. It means the tyre lasted 30 minutes at 575 rpm on the drum, about 115 mph, at the test pressure and load. The speed symbol is the tyre's rating, and speed limits still apply.

Why does my winter tyre have no UTQG grades?

Deep tread, winter-type snow tyres are excluded, as are temporary spares, tyres for rims of 12 inches or less and limited production tyres.

Who checks the grades?

The maker or brand owner assigns them and must make sure the tyre can achieve them. NHTSA runs the test course and uses it for its own compliance testing.

Do UTQG grades apply in the UK, Canada or Australia?

Not as law. The UK and the EU use the tyre label, which has no wear grade. We found no grading requirement in Canada's tyre safety regulations or in the 2007 text of Australia's ADR 23/02 that we read.

Onyx Forged makes forged wheels to order, designed to JWL/VIA standards: see the catalogue.

Sources

• US rule: eCFR, 49 CFR 575.104, including the formula images from the Federal Register and Appendix A; Federal Register, NHTSA notice 2026-06735 of 8 April 2026.
• Data: NHTSA public API, tyre ratings (7,485 records, downloaded and counted by us); US DOT data hub, UTQGS dataset.
• Tyre makers: Continental Tire Canada, What is UTQG; Michelin US, tire markings explained.
• UK and EU: GOV.UK, tyre labelling rules; Regulation (EU) 2020/740, recitals and Article 13 and Annex I, on legislation.gov.uk.
• Canada: Motor Vehicle Tire Safety Regulations, SOR/2013-198. Australia: ADR 23/02, Passenger Car Tyres.

All pages were read on 16 October 2026. NHTSA's own website refused our requests, so its consumer pages were not read.

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