Contact patch
Contact patch size
The contact patch is the only connection between the road and the vehicle. The size and shape of the contact patch as well as the pressure distribution within the contact patch are important to the ride qualities and handling characteristics of a vehicle. Since the wear characteristics of tires is a highly competitive area between tire manufacturers, a lot of the research done concerning the contact patch is considered highly proprietary and, therefore, very little is published on the subject.
Because pneumatic tires are flexible, the contact patch is different when the vehicle is in motion than when it is static. Because it is so much easier to make observations of the contact patch without the tire in motion, it is more common to conduct studies of the static contact patch.
Statically, the size, shape, and pressure distribution are functions of many things, the most important of which are both the load on the tire and the inflation pressure. There are some generalities that can be said about the contact patch of a tire:
- The larger the load on the tire, the larger the size of the contact patch.
- The higher the inflation pressure, the smaller the size of the contact patch.
Unfortunately, both the load and the inflation pressure are not linearly proportional to the area of the contact. Put another way, a 10% increase in load (or a 10% decrease in inflation pressure) doesn’t result in a 10% larger contact patch (except, of course, by coincidence.)
It is also true that calculating the size of the contact patch requires more than just the load and the inflation pressure.
References
External links
This article is licensed under the GNU Free Documentation License.
Last updated on Tuesday September 23, 2008 at 07:48:57 PDT (GMT -0700)
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