Montmelo debriefing
The tribute that was paid to Luis Salom by the spectacle of a beautiful MotoGP event, disputed and fair play, was appreciable.
In terms of tires, the race took place without any problems in terms of safety but demonstrated, once again, that the use of tires can make a big difference.
MIGRAINE AND HEADSHAKE.
If we look at the curves, it is clear that the racing pace has dropped significantly between the start and the end, a sign of wear on the envelopes.
Even between Marquez and Rossi who fought hard until the end of the event, the range of times varied by around two seconds for the Italian and more than two and a half seconds for the Spaniard.
We can also note that the Yamaha riders made a quicker start than the Honda riders.
The Montmello circuit is of the "low-grip" type as is often the case in Spain and if this had already posed a problem in Jerez, it was the rear tires which at that time had been designated as the main difficulty: the slippage problems focused attention. .
Michelin reacted and on this event, even if there were still movements at the rear which greatly affected Vinales, for example forcing him to seek the limit when braking to be able to express his speed, the spectators were able to realize that the limit now came from the front tire.
Indeed, in addition to the somewhat random trajectories of the Suzuki rider, the collapse of Lorenzo and even the percussion which put an end to Iannone's hopes of overtaking his future replacement, have to do with the degradation occurring at this end.
We have already talked about graining right here:
Graining (Randy de Puniet)
Graining (Guy Coulon)
Graining (Nicolas Goubert)
In addition, we can observe that graining also affected Bridgestones.
However, this mainly concerned the rear tire but the degradation conditions were the same: the Japanese slick offered less grip than the French and, on dusty tracks, with little grip, in the event of relatively low temperatures, graining appeared.
In Qatar (desert dust and night track temperatures), in Argentina ('extra-hard' tyre, low temperatures, dirty track), in Phillip Island (hard tires to respond to a circuit this time abrasive, but temperatures still a bit times low).
Graining therefore appears when there is a mismatch between the rubber (if it is too hard), the temperatures (if the tire is insufficiently heated, etc. Which makes the rubber too hard, not very elastic), the lateral forces in relation to the movement of the motorcycle (in other words the crosses or slips which can appear under heavy loads or weak grip).
Concerning Michelin, if, this year, the Argentina race was split into two parts, the front slick suffered graining recorded in Qatar (probably the reason why the Ducati raced with a soft tire at the front) and therefore on this Catalan track, with low grip and a high braking rate.
A priori, these braking should have increased the temperature of the front tire in particular due to the fact that the track itself was hot, but on the Spanish circuits, the higher the heat, the less grip there is and to have stability and withstand decelerations, the choice of a hard rubber was popular.
Dani Pedrosa tried to start in Medium, trying for once to take advantage of his small size in order to preserve his tires (the other drivers ruined the Mediums in 8 or 9 laps), but this was not a decisive calculation.
To win, you had to use a hard tire at the front and either let it warm up (like Marquez) or find another way to go fast.
The two Yamahas attacked very hard from the start of the race, with full fuel; true to his strategy, Lorenzo escaped and took the lead, his teammate having to overtake alternating fast laps with a few slowdowns, while Marquez took his pace.
Lorenzo imposed too many lateral forces on his front rubber, while the maximum elasticity of the envelope was not reached, his riding style, immediate increase in revs and high speed in curves, where the lateral forces are numerous, caused his loss (the appearance of graining), while the braking efforts in line and the control of acceleration on low grip tipped the scales in favor of Rossi and Marquez who were able to drive quickly with marked front gums.
Assen
The Assen track is very different from the Catalan circuit: there are no long straights, the braking rate is relatively low at 18% (old Brembo calculation) of the time spent on the deceleration lap.
There is a high average speed with lots of fast curves and banked turns (banked turns which reduce lateral effort but increase downforce), the temperatures are…random (!), but rather cool.
In summary, it is a rather undemanding track with the front tire, on the other hand, the rear is stressed and Bridgestone, in 2012, had to suffer significant damage at this level, large blocks of rubber separating from the tire carcass mistreated by repeated pressure.
On a sporting level, we will remember Marquez's frustration in the last chicane last year, a frustration which perhaps partly explains the antagonism which opposed the young Spaniard to Rossi. The salutary handshake observed in Catalonia will be put to the test if this scenario occurs again.
For Lorenzo, he will have to recover points, which will not be easy on a track where the banked turns somewhat reduce his ability to maintain more speed in curves than the other drivers.
The Ducati will also have difficulty on a track where the curves are steep and where top speed is not an advantage.
The Suzukis, struggling with an overly reactive rear end, will have a lot of tuning to do...
Please note, this year, the GP will take place on Sunday!
