A wheel and tire assembly seems like a relatively simple structure that's ready to do its job once fitted together, balanced and mounted on your car. However, like many things, it's more complicated than it seems. In years past when suspensions were very "soft" and forgiving, this approach worked a great majority of the time. Though the tire and wheel were actually creating a minor disturbance, it wasn't enough to be felt in the driver's seat.
The system simulates a "road test" that senses the vibrations generated by the wheel and tire.
Today's high performance suspensions, lighter weight vehicles, and lower profile tires have changed all that. Now the slightest vibrations can be felt. Fortunately, with respect to the wheel and tire, there is a solution called Ride Matching. Here's why you need it:
When a wheel and tire are mounted together they are seldom joined at the one ideal spot. Each of these units, though it may be built to specification, frequently adds to the slight error of the other. When combined, they can generate a vibration you can feel.
Tire uniformity is the amount of change in stiffness of the sidewall and footprint when load is placed against the tire. This is one cause of excessive radial force variation.
As they spin together, the tire and wheel exert forces simultaneously in different directions. Thanks to advancing technology, a system has been developed to measure all these forces and calculate how this particular wheel/tire pairing should be matched in order to ride as a perfectly smooth unit.
Lateral and radial rim run-out are other causes of force variation that the system isolates.
It's important to note that the source of disturbance is something that cannot be sensed during wheel balancing. It is an entirely different problem that necessitates Ride Matching. This process takes a skilled operator approximately twenty minutes to perform on a set of tires and wheels for a vehicle. The result, however, improves ride quality, performance and wear (remember that a smooth riding tire lasts longer).
When the system detects a force variation, it prompts the technician to diagnose and correct the problem