The US government established three types of labeling meant to help consumers make an informed choice when purchasing new tires. If a tire maker wants to sell his product on the US market, his tires must feature these labels.
- Treadwear: the tire’s service life
- Traction: traction on wet pavement
- Temperature: overheating resistance
How is treadwear tested?
The U. S. Department of Transportation established a 400-mile loop running through public roads near San Angelo, Texas. Three or four cars drive down this road, one of these cars equipped with reference tires. To make the experiment even purer, every 800 miles the tires are rotated among the cars.
Totally, the cars drive 7,200 miles (11,500 km), after which the controlling body evaluates the actual mileage and forecasts the tire’s total expected mileage, where the entire resource of the reference tire is considered to be 100 points. Hence the Treadwear indexes of 200, 300, and 400. Conditionally, this means that the mileage will be 2, 3, or 4 times as long.
Why this does not work
Of course, long tread life is something to be happy about. However, one must remember that any tire is a compromise of various properties, and, if you see that a tire has a long expected mileage, probably, that was achieved at the expense of compromising some other performance area, such as traction — even though lucky exceptions do happen.
Also, consider the fact that a tire is a complex technological product that can contain 2 or more layers of rubber with different traction and different service life. How can you expect to cover all of these factors, having driven mere 11,000 km?
And the most important thing!
When you look at the Treadwear label, you see an approximate mileage of a conditional «cowboy» driving down American roads. Is it similar to the driving conditions in Russia’s Izhevsk? Not really!
The tread wear is first of all affected by:
- the type of the car;
- the type of road surface;
- your driving habits;
- your climate;
- the conditions and the type of the roads.