Jeff Lacina
December 1, 2008
Photos By: Ron Blevins, V6john
Ahhh...THE smell of freshly shaven tires in the morning air. These brand-new tires have been shaved and are ready for action. It's OK to transport your tires to and from the track on an exposed tire track, but storing them on the rack would expose them to unnecessary sunlight and heat.

It doesn't matter what type of Mustang (or fast Ford) you drive or where you drive it-be it on the street, at the dragstrip, or on a windy road course-tires are an integral part of your car's setup, and in many cases they will help determine the overall handling characteristics. To say the tires are anything but an essential part of the performance puzzle would be a gross understatement. But for something that is an essential element of our automotive enjoyment, there seems to be a huge number of misconceptions and incorrect information surrounding our round, mostly-rubber buddies, all of which give their rolling lives for our fun and transportation.

With that in mind, we set out to piece together an insightful and informative story about tires in order to help you make the right choices when it comes time to fit your Ford with new rubber. We came up with 20 items for you to consider, and after diving into this guide you'll be better educated and rolling fancy.

1 - Tires Are Not Made Solely Out Of Rubber.
Modern tires are made from a range of materials, with the rubber being mostly synthetic. Carbon black is added to increase strength and toughness, as is Kevlar on some high-performance models. When used in the tire's tread, this combination gives long life. Natural rubber is weaker than the synthetic version, and today it is relegated to use primarily in the tire's sidewalls.

During design and construction, manufacturers balance sidewall stiffness and tread pattern and compound to come up with a tire that will perform in the desired arena. Softer tread compounds provide better grip but wear faster.

2 - Tires Are An Integral Part Of Your Suspension.
They act as a secondary spring during all driving conditions. Your tires absorb the hit on launch at the strip and all the loading in a corner. There is far more to the tire's interaction with the suspension than you may think. You can witness this fact just by watching a NASCAR race on TV, as teams adjust the car's handling by adding or decreasing tire pressure by as little as 1/4-lb of air pressure. Often, going with too short of a sidewall can hurt traction as it limits the tire's ability to remain compliant with anything but pool table-like road surfaces.

3 - What Do All Those Numbers Mean?
Today's tires are a veritable alphabet soup of numbers and letters. The sooner you learn how to decode all this information, the better off you'll be. Let's decode just one size, P235/55R/17. The first letter, P, means the tire is a "P-metric" size, which is designed to be fitted on passenger vehicles. The first set of numbers, 235 is the section width of the tire in millimeters. The next number is the aspect ratio of the tire's sidewall when compared to it's section width. In this case, the sidewall height is 55 percent of the section width. The next letter indicates the internal construction type of the tire, with "R" meaning "radial." The final number is the diameter of wheel this tire requires-17 inches in this case.

4 - What is a contact patch?
The contact patch is the actual "footprint" of the tire contacting the road or track. Believe it or not, the contact patch of most tires is only about the size of your hand, and it is dynamic, meaning it changes as the vehicle goes down the road. During acceleration, cornering, and braking, the area in contact changes shape and size.

5 - Tires Degrade With Age.
This is true, even if they have never been mounted on a wheel. This is due to exposure to ozone and sunlight. Keeping unused tires in a dark, cool, and dry environment will minimize their degradation, but not stop it completely. Poor alignment, improper inflation, and abusive driving can also accelerate tire degredation.