There are several good reasons for fleets to keep a close watch over their wheels. Of primary importance is the safety issue, particularly to avoid wheel runoffs when traveling at highway speeds. There's also a cost-control issue. Most of today's wheels can last the life of the truck — if they're properly selected and maintained.
ATA's Technology and Maintenance Council (TMC) publishes the “User's Guide to Wheels and Rims,” which should be required reading for all truck tire/wheel servicing people. Routine visual inspection of wheels should be done by drivers and at regular truck servicing intervals.
In addition, a more detailed inspection of both interior and exterior wheel surfaces should be done whenever tires are changed. Given the trend for fleets to contract out their tire service and retread operations to specialists, the possibility of thorough, standardized, high-quality wheel inspection and refinishing may become a reality. While culling out wheels based on a “clean metal” inspection is not a substitute for normal maintenance, it's certainly a plus. Proper refinishing also facilitates concentric bead seating and air retention.
Like many good maintenance practices, wheel refurbishing isn't rocket science, but it does require consistent attention to detail and quality control. About 15 years ago, International Marketing Inc., followed by several other suppliers, introduced modular wheel refinishing systems to the industry. Since these systems are fairly large, most have been installed in commercial tire dealer and retread locations.
For steel wheels, there are three basic elements of a good program: cleaning, inspection and surface refinishing. There have been significant advances in two of these recently. More durable paint formulations and the increasing use of premium powder-coat finishes on new wheels are designed for high gloss and long life, but are difficult to remove when the time comes to inspect and repaint. Currently, about 10% of new disc wheels for Class 8 trucks are shipped with these finishes.
Since paint removal tends to be the bottleneck in the operation, some refinishers have approached the problem by using larger, more aggressive shots in the blasting medium used to strip the wheels. This gets the old finish off but can cause unnecessary surface etching or roughness. Such surfaces make accurate visual inspections more difficult and require more paint to achieve the desired smooth, high-gloss finish.
Control of paint thickness is extremely important, especially in and around bolt holes and on all wheel mating surfaces. Excess paint can compress after initial torquing, resulting in loss of clamping force, a precurser of loose wheels. Bill Noll, vp-product technology and development for Accuride, says the industry recommends a maximum paint thickness of 3.5 mils.
R&D in the wheel refinishing area appears ready to raise the bar with a new generation of machinery that strips the old finish more consistently. Combine this with advances made in liquid paint material and process technology, and we may find that smooth, glossy refinished wheels will become the norm.
Even with these advances, however, operator training and overall quality control remain important. Truck operators should, as always, look to their vendors for assurance that these are properly addressed. It's no secret that radial truck tire technology has taken major leaps forward in recent years; maybe now it's time for the wheels to shine a little.