Understanding Your Tire’s Limits

Mastercraft® recommends that all tires, including full-size spares, that are 10 or more years from their date of manufacture be replaced with new tires. Under no circumstances should a "maximum" service life recommendation for a tire be considered an "expected" service life. Tires must be removed from service for several reasons, including tread worn down to minimum depth, signs of damage (cuts, cracks, bulges, impact damage, vibration, etc.), or signs of abuse (under inflation, overloading, improper repair, etc.).

Tire service life is not determined by chronological age. The useful life of a tire is a function of service and storage conditions. For each individual tire, this service life is determined by many elements, such as temperature, storage conditions, and conditions of use (e.g. load, speed, inflation pressure, impacts, and road hazard damage), to which a tire is subjected throughout its life. Since service and storage conditions vary widely, accurately predicting the service life of any specific tire based on calendar age is not possible. Mastercraft® is not aware of scientific or technical data that establishes or identifies a specific minimum or maximum service life for passenger and light truck tires. However, Cooper® Tire recognizes a consumer benefit from a more uniform, global industry – wide approach to the tire service life issue. Accordingly, Cooper® recommends that all tires, including full-size spares, that are 10 or more years from their date of manufacture be replaced with new tires. Tires 10 or more years old should be replaced even if the tires appear to be undamaged and have not reached their tread-wear limits. Most tires will need replacement before 10 years due to service conditions. This may be necessary even if the tire has not yet reached its tread-wear limits.

In some cases, a vehicle manufacturer may make a recommendation for tire replacement earlier than 10 years for their products based on their understanding of the specific vehicle characteristics and application. If so, the consumer should follow the vehicle manufacturer's specific recommendations for their vehicle.

The load carrying capacity and inflation pressure capability of the replacement tires must always equal or exceed the load carrying capacity and inflation pressure capability of the original equipment tires.

The replacement tire must have a maximum load carrying capacity equal to or greater than the maximum load carrying capacity of the original equipment tire. Refer to the tire placard on the vehicle for the recommended inflation pressures of the original equipment tires. These pressures must be maintained as a minimum. Do not exceed the maximum pressure indicated on the tire sidewall. Tires that are loaded beyond their maximum allowable loads will build up excessive heat that may result in sudden tire destruction.

Do not exceed the gross axle weight ratings for any axle on your vehicle. Consult the vehicle tire placard and/or owner's manual to determine the gross axle weight rating. Following the loading instructions of the vehicle manufacturer should ensure that the tires are not overloaded.

If the vehicle tire placard and/or owner's manual specify speed-rated tires, the replacement tires must have the same or higher speed rating to maintain vehicle speed capability. When replacing your tires, consult the vehicle tire placard or the owner's manual for the correct size. If the tires shown on the vehicle tire placard do not have speed ratings, the appropriate-size tire with any speed rating may be applied. When the placard tire size contains a speed symbol — for example, P205/55HR16 or P205/55R16 91H — the replacement tire must have the same or higher speed-rating symbol if the speed capability of the vehicle is to be maintained. If the replacement tire is not speed rated, the speed capability of the vehicle is limited by the speed capability of the replacement tire. A Cooper-produced nonspeed-rated passenger tire's maximum speed is 85 mph (137 km/h).

Tire speed ratings do not imply that vehicles can be safely driven at the maximum speed for which the tire is rated, particularly under adverse road and weather conditions, or if the vehicle has unusual characteristics. Never operate a vehicle in an unsafe or unlawful manner.

If replacement tires have lower speed capability than specified by the vehicle manufacturer, the vehicle's speed must be restricted to that of the replacement tire. Also, vehicle handling could be affected. Consult the vehicle manufacturer for recommendations.