2007 Volvo C70 Owner's Manual - Page 141

New Tires Remember that tires are perishable goods. As of 2000, the manufacturing week and year (Department of Transportation (DOT) stamp) will be indicated with 4 digits (e.g. 1502 means that the tire illustrated was manufactured during week 15 of 2002). Tire age Tires degrade over time, even when they are not being used. It is recommended that tires generally be replaced after 6 years of normal service. Heat caused by hot climates, frequent high loading conditions or Ultra Violet (U.V) exposure can accelerate the aging process. You should replace the spare tire when you replace the other road tires due to the aging of the spare. A tire's age can be determined by the DOT stamp on the sidewall (see the illustration above). A tire with e.g., visible cracks or discoloration should be replaced immediately. Improving tire economy Maintain correct tire pressure. See the tire pressure tables on pages 156 and 157. Drive smoothly: avoid fast starts, hard braking and tire screeching. Tire wear increases with speed. Correct front wheel alignment is very important. Unbalanced wheels impair tire economy and driving comfort. Tires must maintain the same direction of rotation throughout their lifetime. When replacing tires, the tires with the most tread should be mounted on the rear wheels to reduce the chance of oversteer during hard braking. Hitting curbs or potholes can damage the tires and/or wheels permanently. 154 07 Wheels and tires Tire inflation Tire inflation Check tire inflation pressure regularly.