WHAT ARE UTQG RATINGS?
You may have noticed markings on the sidewall of your tyres, those are UTQG ‘Uniform Tire Quality Grading’ ratings for Treadwear, Traction and Temperature. The higher the rating, the better the tyre is rated to perform.
The UTQG ratings originated in America. By law, all SUV and Car tyres sold in America must have these ratings marked on the sidewall.
Although, there is no formally-recognised testing for tyres being sold in Australia, this system is as relevant in Australia as in any country. It gives Australian drivers an easy, self-assessing way to factually compare tyres.
TREADWEAR
Treadwear grades are an indication of a tyre's wear rate. The higher the treadwear number, the longer it takes for the tread to wear down.
Treadwear grades are tested under controlled conditions using four vehicles fitted with test tyres that run in convoy. The vehicles repeatedly run a specified 640km road course for a total of 11,520km. Tread depths are measured every 1,280km and the measurements are averaged to give a projected wear-out life.
A ‘standard' control tyre is assigned a grade of 100 and the treadwear rates of all test tyres are compared to it. For example, a tyre grade of 200 should take twice as long as the control tyre to wear out.
TRACTION
Traction grades are an indication of a tyre's ability to stop in the wet. A higher grade should allow your vehicle to stop on wet roads in a shorter distance than a tyre with a lower grade.
Traction is graded from highest to lowest as AA, A, B and C.
TEMPERATURE
Temperature grades are an indication of a tyre's resistance to heat. The higher the grade, the more resistant the tyre would be to the generation of heat at speed. Sustained high temperatures (for example, driving long distances in hot weather), can cause a tyre to deteriorate, leading to blowouts and tread separation.
A tyre's resistance to heat is graded from highest to lowest as A, B or C.
source (http://www.coopertires.com.au/the-cooper-difference/tyres-explained/what-are-utqg-ratings/)