Designate one or more people to work with the tires. Never let an inexperienced person mount or air up the tires. For the sake of performance, have the tire person keep accurate notes on both cold and hot tire pressures, tire temperatures, and tire sizes. By using the same person, your tires will perform consistently week to week.
The tires used for racing have evolved from the best available production car tires years ago to specially built hybrids designed to perform under extreme racing conditions. Each company that produces and distributes stock car racing tires puts thousands of hours into research and development for a tire that will have good performance as well as durability to last the entire race or longer. To take advantage of all of that technology, racers need to know certain facts about preparing and racing tires.
Every team should have a designated tire person or two to select, air up, size, and maintain the tires. A tire program needs to be developed to ensure that the good setups will have a chance to show themselves by having the best tire tech. Based on the type of racing at a particular track, a team will eventually understand the value of knowing what the tires need, and then develop a routine to take care of them.
Tire Selection
Tires are usually selected from a pile of tires at the racetrack. However, there are certain problems associated with this process. One inherent problem is the age of the tires. Older tires may have been mixed with fresher tires, meaning those produced at a later date. One characteristic of racing tires is that the older a tire is, the less performance it will provide. Each tire contains specific chemicals to help it produce grip when heated. If those chemicals evaporate over a period of time, the good characteristics also evaporate, so to speak. Fresh tires will outperform older tires-period.
On-track results can depend on the ability of the tires to carry the car. It helps when you understand the limitations of a tire's performance.
If there is a way to tell a tire's production date or the production run numbers, this will help you pick sets of tires with the same age. Even if they are older, you must have the same age tires in the four that make up each set. Having three older tires and one fresh one will throw the setup off considerably.
Tire distributors don't like to deal with this issue because it is a pain to keep track of the age of their tires. Ask your tire vendor if they can sort the tires by age if they don't already.
Select your tires based on these considerations:
* Hardness or compound (choice usually offered in dirt racing)
* Stagger
* Tread design (dirt tires, based on temperature and track condition for all events)
The proper way to insert a temperature probe is to push it in at a 45 degree angle. Take the outside temperatures in from the outside edge of the tire approximately 1 to 1 1/2 inches. Allow enough time for the reading to settle before recording and moving on.
Tire Pressures
For every type and use of a racing tire, there is an optimum pressure that will provide the maximum amount of traction. The tires normally get their first airing with nitrogen gas that contains very little moisture. There are air pumps that remove much of the moisture in ambient air. In any event, if the gas in your tires has water mixed with it, pressures will increase more so than dry gas. You should start with the most pressure you can get away with and then have the gas expand to the optimum pressures once the tires are heated.
Safety Note: Never over-inflate racing tires. Teams do this with bias tires to stretch the cords to get the tire size consistent and to keep the stagger. The tire manufacturer will tell you how high you can safely go. Extreme inflation pressures have been known to injure and kill team members. The tire will come off the rim at some point, and the force is powerful enough to seriously injure you.
Do not use air hose ends that can be clamped onto the valve stem. If you become distracted, the tire can over-inflate by accident.
Using excessively high or low tire pressures will cause the tire to have a smaller contact patch area and therefore reduce traction. | 
The entire width of the tire may be on the ground, but the whole area of the contact patch is not exerting the maximum pressure on the racing surface. | 
By arranging tire sizes, it's possible to correct a rear stagger problem that arises after the tires have been run and one of them grows more than the other. A 1/4-inch growth probably won't make a significant difference in handling, but a 1/2-inch growth or more will. By planning out the front and rear tire sizes, this errant stagger can be corrected by switching left-side or right-side tires, depending on which rear tire grows. |