2008 Saturn Astra Owner's Manual - Page 248

9-58 Vehicle Service and Care Wheel Alignment and Tire Balance The tires and wheels on your vehicle were aligned and balanced carefully at the factory to give you the longest tire life and best overall performance. Adjustments to wheel alignment and tire balancing will not be necessary on a regular basis. However, if you notice unusual tire wear or your vehicle pulling to one side or the other, the alignment might need to be checked. If you notice your vehicle vibrating when driving on a smooth road, the tires and wheels might need to be rebalanced. See your dealer/retailer for proper diagnosis. Wheel Replacement Replace any wheel that is bent, cracked or badly rusted or corroded. If the wheel bolts keep coming loose, the wheel and wheel bolts should be replaced. If the wheel leaks air, replace it (except some aluminum wheels, which can sometimes be repaired). See your dealer/retailer if any of these conditions exist. Your dealer/retailer will know the kind of wheel you need. Each new wheel should have the same load-carrying capacity, diameter, width, offset and be mounted the same way as the one it replaces. If you need to replace any of the wheels or wheel bolts, replace them only with new GM original equipment parts. This way, you will be sure to have the right wheel and wheel bolts for the vehicle. { CAUTION Using the wrong replacement wheels or wheel bolts on your vehicle can be dangerous. It could affect the braking and handling of the vehicle, make the tires lose air and make you lose control of the vehicle. You could have a collision in which you or others could be injured. Always use the correct wheel and wheel bolts for replacement.