The U.S. Department of transportation (DOT) were the first, who understood, that consumers need help in choosing tires, for more than three decades ago. And ordered manufacturers to conduct tests, “publishing” results on the sidewall of the tire: it shows numeric and alphabetic symbols of wear resistance, grip on wet surface and resistance to overheating.
The first parameter is the wear resistance. In some of the most respected publications in tests of tires this, the most important for the average consumer, option, is bypassed. But for sale in the USA manufacturers of tire are required to conduct this test. PayPerKay offers to get know more about American marking if you want to make a long term car lease in Abu Dhabi.
The method: two (or four) cars go on the caravan for a given route, which does not change over the decades and laid along the neighborhoods of the American city San Angelo, Texas. There are test tires on one car, on another – standard (with known characteristics of wear), which the American community of standardization (ASTM) produces. During the tests, wear of the tires are changed and after a run of 11 520 km tire company, assessing changes of protector’s depth, predict future resource of its selling model.
Treadwear
How much does the tire with an index of Treadwear 200 go? We can argue two times more than standard, but how much exactly in kilometers — even the producers themselves cannot say. Of course, it all depends on a driver and roads.
Traction
The traction parameter defines the tire grip on a wet road in the longitudinal direction during braking. The parameter does not characterize the grip of the tire in the transverse direction, manageability, resistance to aquaplaning etc.
The traction test checks the quality of the tire on wet surfaces only with locking of wheels (without considering of protector’s work). Nowadays, overwhelming number of the tires can easily pass this test and therefore have the marking AA or A.
Temperature — Resistant to Overheating
Unlike the first two tests, this test is carried out in a laboratory on a test reel. The tire under load (88% from maximum) is untwisted till a certain speed and control the temperature. After the test, they check cracks, tears and other defects. The tire, withstood the biggest reel speed 575 rpm (equivalent to over 184 km/h) — gets a rating of A.
