( Department of Transportation)
The letters "DOT" certify compliance with all applicable safety
standards established by the Department of Transportation. Adjacent to
this is the tire identification or serial number. This serial number is
a code consisting of up to 11 digits that are a combination of numbers
and letters.
Ex.) DOT T7 CH A3H 178
(Factory code) (Size code) (Pattern code) (date of production)
T1 : Yp, T7 : Dp, 5M : Kp ... P205/60R15 H406
U.T.Q.G.(Uniform Tire Quality Gradings System)
The DOT requires tire manufacturers to grade passenger car tires based
on three performance factors : tread wear, traction and temperature
resistance.
Ex.)
Tread wear 200 : Indicates two times longer mileage than the master tire
under specified conditions.
* 100 = 30,000 mile = 48,000Km
Traction A : Denotes highest traction grade on specified test surface of
asphalt and concrete
* A (highest) > B > C(lowest)
Temperature C : Poorest grade of tire's resistance heat under specified
test conditions.
* A (highest) > B > C(lowest)
**Definition : The US Department of Transportation (DOT) requires
manufacturers to grade passenger car tires on the basis of three
performance factors: tread wear, traction and temperature resistance.
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1. Tread Wear
The Tread Wear tire mileage grading system is a comparison with the performance of the tire tested under controlled conditions for 7,200 miles at the National Highway Traffic Safety Association (NHTSA). The baseline score of 100 means a tread life of 30,000 miles. For example, "Tread Wear 300" means the tire is expected to last for 90,000 miles under normal conditions. Currently, there are 20 different classifications.
2. Traction
The traction grades relate to the tire performance when tested under conditions specified by the Department of Transportation. Test surfaces are divided into asphalt and concrete.
Asphalt (chart)
Traction grades start in ascending order from C (Acceptable) to A (Best).
3. Temperature
The grade is determined by how long the tire lasts under conditions stipulated by the US Federal Motor Vehicle Safety Standards #109.
A (Best) = 6 hours, 31 seconds or longer.
B (Intermediate) = 5 hours, 1 second to 6 hours 30 seconds.
C (Acceptable) = 3 hours, 30 seconds to 5 hours.
Note: UTQG ratings apply to passenger car radials only. Snow tires or tires with a rim diameter of 12 inches or smaller are not included.
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