There are lots of ways for a wheel to fail. But even with the newest hub-piloted disc, the wheel that’s least sensitive to poor maintenance, the problem can very often be traced to simple cleanliness. The obvious cause of failure may be a loose fastener, usually due to a torquing problem during installation. But what created the lack of sufficient torque to hold things together in the first place?
Chances are, the wheel components were just plain dirty or rusty. And it doesn’t take much dirt or much rust to change things after a few thousand miles. The fact is that even a small amount of dirt or rust or something as small as excess paint drips between mating surfaces will cause a loss of clamping force over time. Note that we didn’t say ‘can cause’ but ‘will cause’.
“Every wheel we put on is torqued properly, of course, but if there’s any rust or dirt or even oil, your torque spec is out the window,” says Jim Wagner, truck-tire sales manager at Bast Tire and Auto Service in Waterloo, Ont.
He’s also a certified trainer in the mandatory Ontario wheel installer’s certification course.
A common failure in disc wheels, for example, is a crack running between bolt holes around the wheel. Its likely causes are a loose wheel nut or worn mating surfaces. Dirt and corrosion will just make it worse.
Similarly, the crack that forms from the bolt hole to the center hole of a disc wheel is usually the result of loose inner cap nuts caused by foreign material between the wheel and the hub or drum. That dirt or rust or whatever prevents a flush contact, and it means the fastener never did manage to make things perfectly tight. Worse, it also means the fastener has been encouraged to loosen up.
Before re-using any undamaged wheel, at the very least use a wire brush or file to thoroughly remove grease, oil, old rubber, dirt, road film and corrosion. This is especially critical in three key areas: where the tire seats, where components fit together, and where the wheels mount on the vehicle.
Be certain to check around the studs on the hub and drum as well as in and around bolt holes and chamfers on the wheels to ensure that they’re clean and flat. Sanding, light sand-blasting or a solvent bath may be needed.
With steel wheels, a lot of people routinely re-paint them at every tire change to help prevent rust and corrosion. If you do it yourself, first make certain that all surfaces are clean and flat and then start with a fast-drying
metal primer. But it’s critical that paint buildup should be avoided on the wheel mounting surfaces and in the bolt holes. Paint should be dry and hard before the wheel is installed.
Another method of wheel refinishing is powder coating, commonly used on things like lawn furniture, though it’s not something you can do yourself. It’s claimed to offer a superior, chip-resistant finish that lasts 40% longer than
paint, and it creates uniform coverage with no runs or excessive thickness, which can also affect clamping force. The best part may be that it’s quick – from start to finish, rims can be ready to have tires remounted in just an hour.
Bast Tire has been refinishing steel wheels this way since the fall of 1998, using the ‘Nucote’ system. It starts with a wash and then bead-blasting that takes the wheel down to bare metal, at which point it’s easy to inspect for cracks and measure bolt holes accurately. Then the powder coating is applied, and finally the wheel is baked in an oven for 20 minutes. As with paint, there’s a wide of array of standard and extra-cost custom colors available. Cost is comparable to paint, at about $30 a wheel for standard
colors, and Bast president Wayne Moser says same-day service is routine.
Whether you use powder coating or not, the very first rule with wheel maintenance is to keep it clean. Remember that dirt and corrosion can do more than compromise a wheel’s appearance.
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