Tread wear indicators (TWI)
Raised areas within the main tread grooves that show, visually, when tires are worn and near the end of their useful life
Uniform Tire Quality Grading (UTQG)
A tire information system developed by the U.S. National Highway Traffic Safety Administration (NHTSA) that is designed to help buyers compare tires. UTQG is not a safety rating, nor is it a guarantee that a tire will last for a certain number of miles or perform a certain way. It gives tire buyers more information to compare with factors such as price, brand loyalty and dealer recommendations. Under UTQG, tires are graded by the tire manufacturers in 3 areas: tread wear, traction and temperature resistance. UTQG information is molded into the tire sidewalls.
U.S. DOT Tire Identification Number (TIN)
A tire's serial number. It begins with the letters “DOT” (“Department of Transportation”) and indicates that the tire meets all federal standards. The next 2 numbers or letters indicate the plant where the tire was manufactured. The last 4 numbers represent the week and year of manufacture.
For example, the numbers 1709 mean that the tire was produced in the 17th week of 2009. Any other numbers are marketing codes used by the tire manufacturer. This information is used to help identify affected consumers if a tire defect requires a recall.
Vehicle capacity weight
The total rated cargo, luggage and passenger load. Passenger load is 150 lbs (68 kilograms) times the vehicle's total seating capacity (as listed on the label inside the driver door).
Vehicle maximum load on the tire
The load on an individual tire that is determined by taking each axle's share of the maximum loaded vehicle weight (GAWR) and dividing by 2.
Vehicle normal load on the tire
The load on an individual tire that is determined by taking each axle's share of the curb weight, accessory weight, and normal occupant weight (distributed according to the table below) and dividing by 2.
Wheel size designation
Wheel rim diameter and width.
Occupant loading and distribution for vehicle normal load for various designated seating capacities
Designated seating capacity, number of occupants Vehicle normal load, number of occupants Occupant distribution in a normally loaded vehicle
2, 3, or 4 2 2 in front
5 3 2 in front, 1 in back
Tires and vehicle load limits
