Tech Q&A: Tommy Baldwin

February 8, 2001
7:14 PM EST (0014 GMT)

Q: How does knowing the tire temperature in practice help NASCAR Winston Cup Series crews know how the tires will wear? Paul Khoury, Nassau Bay

A. You look at all four corners of the tire, looking from the inside of the tire out. You look at the temperature, paying special attention to the right front and the right rear. In the right rear tire, there's a good degree of split. For example, if it's 240 on the inside and 210 on the outside, you either have a camber problem or the car is real loose. Then you look at the right front, to right rear tire temperature to see if the car is tight. Usually you want about five to 10 degrees hotter on the right front than the right rear. After a 30-40-lap long run, if the right rear is hotter than the right front, the car is in a loose condition. Your tire wear and tire temperatures play an important role in how the car is handling.

Q: Why do NASCAR Winston Cup Series teams put Nitrogen in the tires? What purpose does that serve? David Bell, Homer, Alaska

A: We use nitrogen because it's a cleaner air; there's no moisture in it. Moisture builds heat, and when you use compressed air, there's a lot of water in the airlines and air systems, and when that water gets into the tire, it will expand the tire and puts heat into it, and will eventually cause a tire problem.

Q: What effect does moving the front roll center up, down, right, or left have on how a car handles, and is there a ideal place for it? Larry, Denver, Colo.

A. Roll centers effect the way the car handles. A lot of cars and drivers react differently to different roll centers. Usually when you move the roll center up, the car cuts better and sometimes moving the roll center down will help the car cut better. It's really all how the driver feels and how he likes it. We usually use our tests for that a lot. It's something we test at a test track a lot to know what the car will do.

Q: Is it legal, or has anyone ever tried putting sliding, or rolling weights in the frame rails during a race, for the purpose of weight transfer? Dennis H. Jolly, San Diego, Calif.

A. It is illegal. People have tried to do it, putting pellet beads of lead in the car so it would slide back and forth, but they got caught.

Q: When the engine builders put their engines on a dyno. Can they also duplicate weather conditions in the dyno room? Keith Hultsch, New Lenox, Illinois

A. No. It's a set air. They try to get it as close as possible, but it's a set air according to what the conditions are that day. Most of the time, the engine guy has notes from all the previous track so he can adjust from where the air and temperature is at the shop to what it is at the track and how to change the jetting in the carburetor.