Uniform Tire Quality Grading Standards (UTQG)
Also on the sidewall is The Uniform Tire Quality Grade, commonly referred to as the UTQG ratings. You should be aware that each tire manufacturer assigns its own rating to their tires. That is why UTQG ratings are more valuable when used to compare how a manufacturer's tires rate within its own product line rather than as a comparison between brands. UTQG is just one tool to use when selecting tires and it should not be your only guide. However they do offer three more key pieces of information about a tire:
Treadwear
Treadwear is a critical indicator of how much longer your tire will last. In the life of every tire, tread eventually degrades to a degree where the tire can no longer be used safely.
Each type of tire is tested under controlled conditions on a government test course and assigned a treadwear grade which theoretically indicates the useful life of the tread. **It's important to remember that this is a theoretical figure and cannot be linked to projected tire life, as factors like road surface quality, driving habits, inflation, wheel alignment and rotation come into play.
Treadwear grades typically range from 120 to over 700 in 20 point increments. The higher the grade, the longer the tread life as measured under government conditions.
Traction
Traction grades indicate a tire's braking performance. Traction is tested in a straight ahead motion on wet pavement. A grade from "A" to "C" is assigned, with "A" signifying the best traction.
Temperature
Temperature grades represent a tire's ability to withstand heat under test conditions. Since tires are made of rubber and other materials which are degraded by high levels of heat, determining their ability to withstand heat is very important. Temperature grades are also assigned A-C with A signifying the most resistance to heat.
Other Markings
Maximum Load, Maximum inflation
For passenger tires, the maximum load and maximum inflation markings indicate the maximum load that can be carried at the maximum pressure. For light truck tires, it is stated in direct relationship to the maximum load capacity and inflation pressure.
DOT Markings
Essentially the DOT marking serves as the tire's fingerprint. DOT signifies that the tire complies with the Department of Transportation Tire Safety Standards, and is permitted for highway use. For example refer to the following markings: DOT H4 ARDJC 1008 . The first letter and number following DOT designate the tire's manufacturer and plant code. The third to seventh indicate the tire size code and other specific characteristics of the tire. The final four numbers denote when the tire was produced, with the first two indicating the week, and the last two indicating the year (1008 shows the tire was built on the 10th week of 2008).
