Casey Stoner's calls for a softer tire from Bridgestone caused some discussion in the paddock about the merits of the control tire in the sport. Stoner's argument is that the Bridgestones being supplied are too hard, and this is occasionally causing the tires to drop out of their operating temperature in cold conditions, during morning practice and warmup, for example. The evidence - such as it is - would seem to bear this out, with crashes by Valentino Rossi, Hiroshi Aoyama, Ben Spies and others during morning sessions all being put down to cooling tires.
But according to Stoner's Marlboro Ducati teammate, the problem is not so bad. Asked during the Saturday debrief about the conditions at Laguna, and whether the habitual Monterey morning chill caused problems for the tires, Nicky Hayden admitted the chill conditions could be an issue, but that the Bridgestones were significantly improved this season. "This year, the tires are a lot better, as we've seen in qualifying," Hayden asserted. Much of the improvement was down to Bridgestone bringing an asymmetric tire to Laguna, something the spec tire supplier had not done in 2009. "The dual compound here was a must," Hayden said. "So thanks to Bridgestone, because in the morning session and even on out laps, it's a lot more fun to ride when you've got more grip."
The problem still remains in chilly conditions, especially when the air temperatures are cold. What appears to happen is that the less-used part of the tire (the left shoulder at tracks with mainly right-hand corners, and vice versa) cools down in cold air conditions, dropping to the lower end of the tire's operating conditions. The problem is in part the result of Bridgestone's success at producing tires that have such a wide operating range. The tires are so good, and can be pushed so hard in such broadly differing conditions that riders get used to the tires working just about all the time. If the tires lose just a little bit more grip than the riders had been expecting, they can find themselves in more trouble than they anticipated. Ironically, when tires are less predictable and provide less grip, rider caution ensures that they maintain a bigger safety margin, reducing the risks of sudden highsides.
It remains to be seen how Bridgestone will respond to the problem. Tires for most of the remaining rounds have already been shipped to their destination, and so a response in the next couple of races is unlikely. But Bridgestone will be examining the data from 2010 at the end of the season, and working on solutions to this problem for next year.