Wheels must run for hundreds of thousands of miles, through over the years they can become damaged, crack, or weaken from rust or corrosion. A major American wheel manufacturer estimated that one out of every seventy wheels on American vehicles needed replacing, meaning about one out of every seventeen vehicles may have potentially unsafe wheels.
It is a good idea to inspect your wheels periodically, typically at the time you are changing, balancing and rotating tires or when any brake or suspension repairs are being done. Some damage can be readily observed, such as bent rims or wheels not properly balanced. Inspect the lug nut holes for any signs of deformity or elongation, which can cause lug nuts to work loose, or result in the wheel wobble. Corrosion damage, or metal fatigue from pothole and curb impacts, is usually harder to find. Besides fatigue, cracks can be caused by over-tight lug nuts, incorrect lug nuts, improper installation, tire over-inflation, vehicle overloading. These hairline cracks can grow and eventually cause the wheel to fail.
Newer wheels made of high-strength, heat-treated steel (HSS), which uses a thinner gauge of steel with a high strength to weight ratio, are also especially prone to heat damage. HHS wheels. Therefore, never use heat to loosen a frozen lug nut on HHS steel wheels.
Rust and other corrosion can damage wheels, which are especially susceptible in any corners and cracks, or at welds and rivets attaching the center section to the rim, the wheel mounting surfaces and the bolt and center holes. These are the locations of highest physical stress in the wheel. If corrosion is pitting in the rim and your tire is losing air, you should definitely replace the wheel.
A cracked, seriously corroded, bent or sprung wheel should not be repaired. Discard it, but only after you have made it unusable by someone else.
Many professional mechanics and tire stores use air-driven impact wrenches because they save time and physical effort. They are good for removing lug nuts, but should not be used for reinstalling the nuts and especially not for the final torquing, which should be done with a torque wrench. The nuts should be tightened to the vehicle manufacturer's specifications. Excessive torque applied by an impact wrench may distort the roundness of the bolt holes, strip threads, or even shear off the stud.
Always tighten the nuts in a star pattern on wheels with an odd number of nuts. On wheels with an even number of nuts tighten in a cross pattern. This will assure even loading and helps retain the torque for miles and miles of driving.
If you do not have the Owner's Manual, you can use the following torque values as a guide: