Wheels are very reliable and therefore probably one of the most neglected parts on a vehicle. Most go around for hundreds of thousands of miles usually without a lick of trouble. However, through the years they can become damaged, crack or become weakened by rust and corrosion.

Kelsey Hayes, one of the largest manufacturers of automotive wheels, once estimated that one out of every seventy wheels on American vehicles needed replacing. With at least four wheels on most vehicles, this means that about one out of every seventeen vehicles is traveling around on potentially unsafe wheels.

It is a good idea to check wheels out periodically. The best time for inspection is when you are changing, balancing and rotating tires or when having brake and suspension repairs done.

Some damage, like bent rims, will be obvious as will wheels that cannot be properly balanced. Other damage is sometimes harder to find. What might appear to be just minor damage or corrosion might be serious enough to threaten the integrity of the wheel and indeed the safe operation of the vehicle itself.

Wheels are subjected to high impact loading and flexing especially when the tire hits a curb or falls into a pot hole. Tires absorb most of the shock, and they will blow after thousands of such encounters. The wheel itself can suffer metal fatigue resulting in hairline cracks forming. Besides fatigue, cracks can start by over-torquing (tightening) the lug nuts, using the wrong lug nuts, improper installation, over-inflation, overloading the vehicle, or just from old age. These hairline cracks can grow and eventually cause the wheel to fail.

While older wheels are subject to cracking, newer wheels made of high-strength, heat-treated steel (HSS) are also especially prone to heat damage. HHS wheels are common today because they use a thinner gauge of steel providing high strength with low weight. Unfortunately, heat can distort and/or dangerously weaken HHS wheels. Therefore, never use heat to loosen a frozen lug nut on HHS steel wheels.

Both rust and other types of corrosion can damage wheels. Look for rust and corrosion in corners and cracks. Especially check the welds and rivets attaching the center section to the rim, the wheel mounting surfaces and the bolt and center holes. These are usually the locations of highest stress in the wheel. If you are losing air because of corrosion pitting in the rim, replace the wheel.

Inspect the shape and condition of the bolt holes. If the holes are deformed or elongated, they will probably not hold the proper torque. Deformed holes can also cause lug nuts to work loose or result in the wheel wobble. Be sure to carefully inspect the bolt holes on any wheel where studs have been sheared off.

If you find a cracked, seriously corroded, bent or sprung wheel it probably cannot, and 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. While okay for removing lug nuts on newer vehicles, impact wrenches really should not be used for reinstalling the nuts and especially not for the final torquing. If an impact wrench is used for installation, a torque wrench should be used for final tightening.

The torque applied by an impact wrench can vary from nut to nut. This can cause uneven loading of both the wheel and hub, and allow the lug nuts to work loose after miles of driving. Excessive torque applied by an impact wrench can also distort the roundness of the bolt holes, or even shear off the stud. It can also start a crack that will grow with time. If the nut should be accidentally cross-threaded, an impact wrench can cause stripped threads before you know it.

It is very unpleasant to try removing a wheel when on the side of the road - usually in pouring rain - only to find that the garage has overtorqued the lug nuts making it impossible to remove a couple. The nuts should be tightened to the vehicle manufacturer's specifications. If you do not have the owner's manual, you can use the following torque values as a guide:

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.