Photos: Track tech at the San Jose Grand Prix

After each session, engineers use probes to test the temperature of each of the car's tires, checking for underinflation or overinflation. Three readings are taken across the span of each tire: if the middle is hotter than the outsides, it means the center section of the tire is getting more ground contact than the edges, in which case the tire is overinflated. If the edges are hotter, then the tire is underinflated.

Photo by CNET Networks