traction and contains the gas or fluid that sustains the load.
Production options weight: The combined weight of installed regular production options weighing over 5 lbs (2.3 kg) more than the standard items they replace,
and not previously considered as curb weight or accessory weight. These include, for example, heavy-duty brakes, ride levelers, roof rack, heavy-duty battery, and
special trim.
Radial ply tires: A pneumatic tire in which the ply cords that extend to the beads are laid at substantially 90 degrees to the centerline of the tread.
Recommended inflation pressure: The tire pressure recommended by the vehicle manufacturer for a tire of a specified size that has not been driven for more tha
a couple of miles (kilometers) at low speeds in the 3 hour period before the tire pressure is measured or adjusted.
Reinforced tire: A tire designed to operate at higher loads and at higher inflation pressures than the corresponding standard tire.
Rim: The outer edge of a wheel upon which the tire beads are seated.
Rim diameter: The nominal diameter of the wheel's tire bead seating surface. If you change your wheel size, to wheels of a different diameter, you will have to
purchase new tires to match the new wheels.
Rim size: Designation means rim diameter and width.
Rim type designation: The industry or manufacturer's designation for a rim by style or code.
Rim width: The nominal distance between wheel rim flanges.
Section width: The linear distance between the exteriors of the sidewalls of an inflated tire, excluding elevations due to labeling decoration, or protective bands.
Sidewall: The portion of a tire between the bead and the tread.
Sidewall separation: The parting of the rubber compound from the cord material in the sidewall.
Speed rating (letter code): A standardized letter code indicating the maximum speed at which a tire is designed to be driven for extended periods of time. The
ratings range from 93 mph (150 km/h) “P” to 186 mph (300 km/h) “Y”. The speed rating letter code, where applicable, is molded on the tire sidewall. You may not
find this information on all tires because it is not required by law.
Tire Pressure Monitoring System: A system that detects when at least one of a vehicle's tires is underinflated and illuminates a low tire-pressure warning light.
Tread: The portion of a tire that normally touches the road.
Tread rib: A tread section running circumferentially around a tire.
Tread separation: Tire failure caused by the tread pulling away from the tire carcass.
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 manufacturer
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 meet
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 (a
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
5, 6, or 7
2
3
2 in front
2 in front, 1 in back
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