The infra red pyrometers measure the surface temperature of tires and the surface changes temperature rather quickly. Knowing this, you will have to be a quick-draw to get the most useful information. Now, what do you do with the data? Race drivers measure the inside, outside and middle of the tire and, to them, the data guides modifications to pressure, suspension, etc. to maximize overall efficiency. It's important to have the tire manufactures temperature guidelines before any useful purpose can be realized by using the pyrometer. Using web explanation:
Center of tire is hotter than edges
Tire pressure too high. Reduce 1 psi for each 5' F delta.
Edges of tire is hotter than center
Tire pressure too low. Add 1 psi for each 5' F delta.
Inner edge is hotter than outer edge
Too much negative camber.
Outer edge is hotter than inner edge
Not enough negative camber or too much toe-in.
Tire is below ideal temperature range
Tire pressure too high, tire too wide, or springs/sway bars too stiff at that axle.
Tire is above ideal temperature range
Tire pressure too low, tire too narrow, or springs/sway bars too soft at that axle.