Marc Christ
Brand Manager, Modified Mustangs & Fords
February 1, 2013

Contact Patch
Though tires appear to be a very large part of the vehicle, the actual amount of tread contacting the pavement at any given time is very small. In fact, most tires have a contact patch no bigger than your hand. And the weight of the vehicle must be distributed across four of those small "contact" patches. Many factors contribute to a tire's contact patch, including tire width, aspect ratio, tire pressure, weight of the vehicle, and wheel width.

The few factors that are typically altered to apply a larger contact patch on a tire are tire width and tire pressure. After seeing how little of a tire is actually contacting the pavement, you can see how even adding 10 mm to the width of your rear tires will help you get much more traction on acceleration.

In drag racing, it's common for racers to lower their rear tire pressures to 16 or 18 psi (with drag radials), and slicks can be run as low as 10 psi or below. This allows the contact patch to be enlarged greatly, and the reduced pressure allows the wheel to "wrap up" the side wall to absorb the intial shock of the launch, thus aiding traction from a dig. Drag cars run skinnies in the front to lower rolling resistance by creating a much smaller contact patch. With a street car or open track car you aren't as concerned with creating a dead hook, but are more concerned with overall performance, be it acceleration, braking, or turning.

The Life of Your Tires
There are a number of factors that help preserve the life of your tires. Tire composition, driving style, alignment, tire pressure, and tire rotation all play a role in how long your tires last. But if you're good to your tires, and you don't put that many miles on them, your tires still may need to be replaced because of age.

Maintaining your tires to get the most out of them is easy if you do a few simple things. First, maintain proper tire pressure. Check your tire pressures every few weeks, or when you check your engine oil. A low tire won't only wear prematurely, but it's also dangerous—most blowouts are caused by incorrect tire pressure and can cause poor miles per gallon.

Another important aspect to the life of your tires is proper alignment. Immediately after installing a new set of tires, get an alignment. Replace worn suspension parts while you're at it. Your tires will thank you. And just because you got an alignment "a few months ago" doesn't mean that you don't need another one. Depending on driving habits and road conditions, you should get an alignment every six months to a year.

Finally, don't forget to rotate your tires. And just because you have directional tires or staggered wheels doesn't mean you can't rotate your tires. See the diagram on tire rotation for more information.

And if you've been good to your tires, and they've lasted a long time, you may have to replace them before they wear out. In fact, most tire manufacturers recommend replacing your tires after six years, whether they're worn out or not. But how do you tell how old your tires are?

Aging tires is easy. If you look on the inside of the tire, near the bead, there is a DOT number. At the end of that number is a four number date stamp. The first two numbers indicated the week of the year, and the second two numbers indicate the last two numbers in the calendar year that the tire was manufactured. So, for instance, if a tire was made in the eleventh week of 2013, then the date stamp would read 1113.

Selecting the Right Tires
With the help of tire distributors like www.tirerack.com, www.americanmuscle.com, and Latemodel Restoration, finding the right size wheel and tire combination for your car is quite simple. But if you take the time to do your research, use the tools we've provided in this article, and use a little imagination, you can set your Steed apart from the rest.

If you're going to drive your car mostly on the street, then buy tires meant for the street. If you track your car a lot, get a set specifically for that. As you can see, not all tires are built alike. Decide how much money you want to spend, start pricing out different combinations, and you may be surprised what you come up with.

Numerous choices, mixed with confusing misinformation can cause people to just make a knee-jerk reaction.

Many factors contribute to a tire's contact patch, including tire width, aspect ratio, tire pressure, weight of the vehicle, and wheel width.