Corrosion Versus Wheels
Special finishes for new wheels and proper maintenance for those already on the truck can win the war.
Tom Berg
Equipment Editor
Corrosion - called rust when you're talking about iron and steel - is a natural force that eats away at metals. Left unchecked, it burrows deep into wheels.
Corrosion is aided and abetted by road departments that use aggressive salts to melt ice and snow on pavements. Rock salt works well on pavement and can be fairly easily washed from vehicles to protect them. But the far more efficient magnesium- and calcium-chloride compounds are more corrosive and cling tenaciously to metal. Wheels are literally closer to salt sprays than anything else on the truck, so they need extra defensive measures to protect them.
Materials matter. Aluminum resists corrosion better than steel, which is another argument for buying aluminum wheels. Many truckers already choose aluminum for its weight savings and for the bright, shiny look when they're polished.
But aluminum can be dulled by salt sprays and acid baths at commercial washing facilities. As a result, many owners clean and wax them often. If neglected, aluminum takes on a whitish film that doesn't wash off but can be removed by laborious polishing. Some entrepreneurs offer this service in freelance fashion on truckstop parking lots.
New aluminum wheels can be spec'd to stand up better to corrosion. Special finishes - called Accu-Shield by Accuride and Dura-Bright by Alcoa - keep the wheels shiny. The makers say their special wheels can be cleaned with soap and water, and never need polish or wax.
Alcoa says its Dura-Bright is the result of a chemical-thermal processing that toughens aluminum surfaces. The process can be applied to polished and non-polished wheels, but about 90% of Dura-Bright sales are to folks who spec polished wheels, Alcoa says. Expect to pay $75 to $80 per wheel for the special surfacing (by comparison, factory polishing costs $30 to $50 a wheel, depending on pricing by vehicle builders). The finishing is done at the factory and can't be applied to existing wheels unless they're removed from a rig and sent in - not always practical.
Steel wheels can also get special treatment. For example, Accuride and Motor Wheel (a unit of Hayes-Lemmerz International) offer powder top-coatings on their steel disc wheels that should last two to three times longer than standard paint.
Powder coating is electrostatically sprayed over e-coat primer, which itself is electrostatically applied over a zinc phosphate treating.
White, grey and black are the usual hues for standard and powder-coated finishes. But they can be custom colored in red, blue, green, pink or whatever a customer wants. Other optional finishes might be available from other companies. Ask the truck salesman about this, or visit a manufacturers' web sites.
How should existing wheels be maintained? Manufacturers offer tips printed on handy wall charts and on web sites. Because company representatives are usually members of the Technology & Maintenance Council of ATA, much of their advice is incorporated into TMC recommended practices. These can be boiled down into three key activities:
• Cleaning - The object is to remove dirt, loose paint and rust without cutting into the metal, says the "wheel reconditioning" section of Recommended Practice 222B. So aggressive blasting with sand or other media should be avoided. Ask the wheel's manufacturer which cleaning method it considers best.
• Inspection - Look for fatigue cracks, pitting, elongated holes and other damage that can put the wheel out-of-service. Fix any flaws according to makers' approved methods before painting. A good paint shop won't paint a wheel with damage that should render it out-of-service.
• Painting - The type of paint is not critical to safety, but the thickness is, the RP says. Paint thickness should not exceed three-thousandths of an inch. Too much paint can be compressed by fasteners over time, and the bolts can loosen.
Paint that's to be air-dried should be allowed to cure for three days, and baking can quicken that. Powder coating will last longer than regular painting, and specialty shops can do the work, although quality varies.
Another way to protect wheels is to use wheel guards, or spacers. These nylon discs are placed in the bolt-hole circle between the hub or brake drum and a wheel, or between two wheels in dual applications. Wheel guards should be cleaned when wheels are removed for servicing, and replaced at every tire change.
