The new 2012 spec Bridgestone...
The new 2012 spec Bridgestone tires have induced a midcorner chatter with most of the MotoGP bikes, and Casey Stoner hopes Honda has solved the problem at Sepang.
SEPANG, MALAYSIA, JAN 30 – Repsol Honda’s Casey Stoner doesn’t think the new, user-friendly control Bridgestone tires are causing chatter, he knows it.
“When you go from the old tires with no chatter to the new tires and your fillings are falling out, it’s definitely the new tires,” Stoner said at the Repsol Honda team launch on the eve of the start of the 2012 testing season in Sepang, Malaysia.
Stoner tested the Honda RC213V three times last year, first in Jerez, then Brno, and finally in Valencia at the end of the year. The chattering became an issue when the larger displacement Honda was fitted with the 2012 Bridgestones, tires that warm up faster at the expense of durability. Bridgestone made changes to the control tires after complaints from riders that they were sketchy in the opening laps, and after almost every rider suffered some kind of cold tire crash.
Neither Stoner nor his team can pinpoint the cause of the chatter, “but it definitely changed the bike completely. From a bike that we were pretty happy with and didn’t have any chattering issues to all of a sudden it just being ridiculous, then yeah, we pinpointed it. But unfortunately with tire competition we’d be able to get this fixed, but now it’s the single tire rule.”
The solution is that his team, like all teams, has to adapt the motorcycle to the tires, rather than the other way around. Said Stoner, “I’m pretty sure we’re not the only manufacturer with it. From what I heard in the Valencia test, Yamaha and Ducati have basically the same issues. We’ve got to all, I suppose, change our bikes, rather than just tires to change that. because I think they’ve already gone into production and are already made.”
The RC213V was extensively tested in Japan following the MotoGP season, but Stoner believes it’s a problem his team has to fix. He said between his input and the data, they can see the area and the frequency of the chattering. Honda’s engineers will use that information to adjust the stiffness of the chassis, if it comes to that. The team already tried changing engine braking and adjusting tire pressures, “but nothing worked. So we have to go towards the chassis to try to improve that problem and hopefully what we have here is something that can at least get us somewhere in the ballpark where the changes we can make actually make a difference. Whereas we went to the limits of the chassis last time, we couldn’t really improve too much. We did a little bit, but still not enough.
The follow-on test in Sepang starts on Feb. 28, 26 days after this test ends. Stoner was sure Honda could build another chassis, but it wasn’t something he was expecting. “I’m expecting us to be able to sort out whatever we’ve got here and now, but if we can’t, and we’ve tried a lot of different things and we can’t really improve it, we’ll try to come up with a different solution, whether it’s chassis or whether it’s just internally, clutch, different things like that. And doesn’t necessarily have to be chassis. But yeah, we’ve to put it all together to try and make the difference.”
Interestingly, Stoner wasn’t sure if the chatter was coming from the front or rear tire, “but these tires do seem to warm up a little faster than what we’ve had in the past. Other than that, they’re exactly the same. But the fact they’re warming up quicker says they’re not exactly the same. It is definitely an improvement with the warm-up performance, because as we’ve seen, so many riders were taken out of the championship or races or, if not, very close to with big crashes, so it’s something that needed to happen and hopefully they’ve improved that in all different circumstances. At the moment we’ve only ridden them in quite good circumstances, so we’re just going to have to wait and see. Other than that, we’re just going to have to try to mold the bike around those tires.”