"Air in the tyre is not a problem," Speyer commented. "It's the moisture that gets in the tyre. If you go over the boiling point of water, which can happen in these tyres, that moisture turns to steam and you get an uncharacteristic tyre build-up. So a lot of teams used to take the air out and put nitrogen in.
"We worked a lot with air driers so that the air we inflate the tyres with is virtually moisture-free. By doing that, it eliminated the need for the tyre guy to take that extra step and reinflate the tyres with nitrogen. It's just another piece that we did. It probably saved the tyre guys a lot of time and effort."
Mader emphasised the need for precision and repeatability.
"It's making sure you do everything the same all the time," he observed. "It's doing your job and each part of it identically, whether it's the mixing of the compound or the materials you use or the process of putting them together and the curing process. You've got to make sure that all of these processes are the same.
"When you make tyres like the street course tyre we run in Long Beach and six or seven races, we make them primarily in one production group for the whole year. We do everything we can to try to guarantee consistency. But, invariably, we might need some more tyres, or there are some left over from last year, or maybe the workshop built half of them, then had to build something else."
Tyres that are more than two years old are discarded.
"We have age limits," Speyer said, "You won't find a tyre out here that's three years old. The tyres are never more consistent than when they leave the trailer. Even just sitting in the sun can make changes to them. If people use tyre heaters in testing, it's the same as running it on the track. It's gone through one heat cycle."
Mader itemised the combination of tyres
Bridgestone Firestone builds for Champ Car and IRL.
"We've got street course, road course, short oval and superspeedway tyres," he explained. "Basically, for the slower tracks like the street courses, you need maximum grip, softer construction and good response. As you progress to the road courses, you need more stability because you've got more downforce and faster corners, so you also need a more durable compound.
