1994 Chevrolet Astro Owner's Manual - Page 270

Temperature - A, ByC The temperature grades are A (the highest), B, and C, representing the tire's resistance to the generation of heat and ability to dissipate heat when its tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the materialthe tire to of degenerate and reducetire life, and excessive temperature can lead to sudden tire failure. The gradeC corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law. Warning: The temperature grade for this tire is established for a tire thatis properly inflated andnot overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure. These grades are molded on the sidewallsof passenger car tires. While the tires available as standard optional equipment on General or Motors vehicles may vary with respect to these grades, all such tires meet General Motors performance standards and have been approved use on for General Motors vehicles. All passenger type Metric) tires must conform (P to Federal safety requirementsin addition to these grades. Wheel Alignment and Tire Balance The wheels on your vehicle were aligned and balanced carefully at the factory to give you the longest tirelife and best overall performance. In most cases, you will not need have your wheels aligned again. to However, if you notice unusual tire wear your vehicle pulling way or or one the other, the alignment may need be reset. If you notice your vehicle to vibrating when driving on a smooth road, your wheels may need to be rebalanced. Wheel Replacement Replace any wheel that is bent, cracked badly rusted. If wheel nuts keep or coming loose, the wheel, wheel bolts, and wheel should be replaced. If nuts the wheel leaks air, replace it (except some aluminum wheels, which can sometimes be repaired). See your GM dealer if any of these conditions exist. you Your dealer will know the kind of wheel need.