2005 Cadillac STS Owner's Manual - Page 356

If you replace your vehicle's tires with those not having a TPC Spec number, the tire pressure monitoring system may give an inaccurate low-pressure warning. Non-TPC Spec tires may give a low-pressure warning that is higher or lower than the proper warning level you would get with TPC Spec numbered tires. {CAUTION: If you use bias-ply tires on your vehicle, the wheel rim flanges could develop cracks after many miles of driving. A tire and/or wheel could fail suddenly, causing a crash. Use only radial-ply tires with the wheels on your vehicle. Vehicles equipped with performance tires P235/50R17 95V (front axle) and P255/45R17 98V (rear axle) are mounted on wheels with different rim widths. The front axle tires are mounted on rims 7.5 inches (19.05 cm) wide and the rear axle tires require wheels with a minimum rim width of 8 inches (20.32 cm). The original equipment wheels designed for P255/45R17 98V size tires are etched with the words REAR ONLY. When replacing P255/45R17 98V size tires have them mounted on wheels with a minimum width of 8 inches (20.32 cm) and marked REAR ONLY. See Wheel Replacement on page 5-68. {CAUTION: Mixing tires could cause you to lose control while driving. If you mix tires of different sizes (other than those originally installed on your vehicle) or types (radial and bias-belted tires), the vehicle may not handle properly, and you could have a crash. Using tires of different sizes (other than those originally installed on your vehicle) may also cause damage to your vehicle. Be sure to use the correct size and type tires on all wheels. It is all right to drive with your compact spare temporarily, it was developed for use on your vehicle. See Compact Spare Tire on page 5-82. 5-66