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Wheel slippage has long been a point of concern in the tire industry, usually with high output engines and high torque applications - primarily farm equipment and commercial trucks.
For the most part, these tire/wheel slip situations caused little more than brief consternation and had minimal impact on tire or vehicle performance. Generally, they occurred after a new tire was mounted, and the cause could be traced to overaggressive bead and rim lubrication, poor mounting techniques, bead area damage or wheel-related problems.
Occasionally, wheel slippage would be considerable and lead to tire or vehicle damage. But in most cases, the tire would settle in place quickly and there would not be any long-term performance problems.
But now one tiremaker says that wheel slippage is a "major cause" of passenger vehicle ride comfort and vibration complaints by performance tire customers.
Toyo Tire (USA) technicians conducted a series of on-road tests using a variety of tire brands and sizes mounted on both OE steel and alloy custom wheels. The testing was the result of Toyo efforts to help some of its dealers determine the cause of persistent ride vibration complaints with a range of tire and wheel brands.
The tiremaker discovered that in almost every case, "excessive use of lubricant on the tire beads and rim" was the cause of the tire/wheel slip.
In most cases, technicians discovered, paste-type lubricants were used, but were liberally applied to the bead area and on the bead seat and rim flange areas of the wheel - far too much paste in far too many places, the engineers concluded.
Cause and Effect
In these days of lighter front-wheel drive sport performance applications, high torque caused by aggressive acceleration and/or braking make these vehicles highly susceptible to tire/wheel slip. Lighter rear-wheel drive performance vehicles are also likely to be affected.
Today's suspension and steering systems, made lighter but stronger by carmakers in an effort to increase CAFE mileage and overall performance, are far more sensitive to tire/wheel-caused vibration. Match-mounting and careful high speed balancing are the most popular ways tire dealers have to combat tire/wheel-related ride complaints.
But wheel slippage can be so severe - three inches or more, technicians found - that previous match-mounting and balance efforts were for naught.
In their investigation, Toyo technicians mounted a variety of new tires on OE and aftermarket wheels. They used a common paste lubricant liberally on both the tire beads and bead seat areas of the wheel, mimicking the process used by some of the affected dealers. The tires were then indexed to their wheels with a crayon mark on the tires by the valve stems. The tire/wheel assemblies were then balanced using a Hunter GSP9700.
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