The 2016 MotoGP championship will begin in two days in Qatar. The pre-season tests are completed and it is time to take stock aimed at identifying the fundamental differences existing between Bridgestone and Michelin, then a summary of what we could observe on the subject during the off-season tests.
Here is the first part of this article.
Michelin versus Bridgestone
During previous seasons, and after Bridgestone became the first sole supplier of MotoGP tires, riders naturally adopted the brand's standards.
They did it all the more easily since Stoner was the first to use these tires in the world title in 2007 (Bayliss and Capirossi had introduced the Japanese tires on the Ducati in 2003). Rossi followed suit with the same success the following year: it seemed logical that what appeared to be the best tire would equip the best in motorcyclist speed.
The fastest Michelin driver in 2008 (Lorenzo) also quickly showed himself to be efficient by adopting the "Bridges" and concluded with a coronation in 2010, which, moreover, could suggest that very different drivers could express themselves on this mount.
The standard of Japanese tires is based on a rigid construction with a carcass allowing low inflation pressures, with the consequence of a substantial increase in the surface in contact with the ground, following to a certain extent the increase in the loading of the tire .
This development concerning the front tire makes it possible to change its profile, which will have a significant influence on the way you drive: in fact if, at Michelin, it is necessary to use a “V” design of the rubbers so that once the motorcycle is inclined in a turn, the contact surface with the ground is greater, thus satisfying the need for grip induced by the application of centrifugal force, it is no longer such a big constraint for the Bridgestone.
If until 2006-2007, a MotoGP is not asked to be stable (it's up to the rider to put up with it) but to be efficient in curves, Bridgestone is initiating a change in philosophy which will be decisive : the front tire, by becoming less pointed, will offer not only greater progressivity when setting the angle, but also an increase in the contact surface when the motorcycle is not yet inclined, and therefore the possibility of braking more strong and prolong deceleration in curves by limiting variations in grip.
This characteristic will be appreciated by big brakers like Rossi, but also by drivers who maintain a lot of speed in turns and who need progressiveness, fluidity in cornering, and good feedback. tire information regarding grip.
In terms of rubber, Bridgestone also offers special chemistry by introducing compounds offering high-level grip.
At this stage, the results may seem idyllic but the criticisms are starting to appear: in 2010, Rossi, although ambassador of the brand, declared that the Japanese tires “scare him”: the rigidity of the carcass indeed requires an attack of all the moments to maintain a correct operating temperature, and if there is a succession of turns on the same side, all it takes is a little coolness for the opposite side of the tire to cool down and trap the driver in the first alternate turn...
While Bridgestone tries to resolve the problem, the MotoGP regulations change: exit the 800cc, return of the 1000cc!
The weight and the increase in available torque will undermine the rear flange, which will experience spectacular destruction, tarnishing Bridgestone's performance image.
The successive changes concerning the carcass, made with the aim of having better heating, will also generate marked differences which will favor different types of riding, making any idea of pneumatic universality disappear.
Thus, from 2007 to 2011, very rigid tires will satisfy Stoner and Rossi, while in 2012 and 2013, a reduction in rigidity will suit Lorenzo and Pedrosa. The times progress from year to year, (but safety is called into question by the aforementioned destruction) to decrease in 2014, a relatively "slow" season where the "Bridges" regain their rigidity... And will fit very well with Marquez , which will outrageously dominate this year.
On the other hand, 2015 will be that of versatility, since if this year is marked by a disappointment on the machine side at Honda, drivers as different as Rossi, Lorenzo, Marquez and Pedrosa, record victories, all without the slightest tire destruction.
In 2015, the carcasses are similar to those of 2014, but the tires have progressed on the rubber side: the heating is regulated by the carcass and "bigomme" tires, even sometimes with asymmetrical rubbers, (the tire allocation is now really specific to each route) are becoming more widespread, giving both excellent load resistance during heavy braking, high-level grip, and a warm-up that suits the majority of drivers.
It is on this laudatory observation that Michelin is in turn inducted as sole supplier of MotoGP.
To be continued…
