H up to 130 mph (210 km/h)
V up to 149 mph (240 km/h)
Z over 149 mph (240 km/h)
W up to 167 mph (270 km/h)
Y up to 186 mph (300 km/h)
Some tire manufacturers label tires with a maximum permissible road speed above 149 mph (240 km/h) with the letter combination “ZR”.
WARNING
Using incorrect or unmatched tires and/or wheels or improper tire and wheel combinations can lead to loss of control, collision and serious personal injury.
x Always use tires, wheels and wheel bolts that meet the specifications of the original factory-installed tires or other combinations that have been specifically approved by the vehicle manufacturer.
x All 4 wheels must be fitted with radial tires of the same type, the same size (tread circumference), and the same tread pattern. Driving with different tires reduces vehicle handling and can lead to a loss of control.
x Never drive faster than the maximum speed for which the tires installed on your vehicle are rated because tires that are driven faster than their rated speed can fail suddenly.
x Overloading tires can cause heat buildup, sudden tire failure, including a blowout and sudden deflation and loss of control.
x Temperature grades apply to tires that are properly inflated and not over- or underinflated.
Winter tires
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 than 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 or 150 km/h (“P”) to 186 mph or (300 km/h) “Y”.
The speed rating letter code, where applicable, is molded on the tire sidewall ⇒ Speed rating code letter. 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.