Choosing the right tyre for a race is often the key to victory.
Michelin is the supplier of the tyres used by the World Championship riders. Before the MotoGP, all riders meet with their teams to choose from among the three compounds offered by the manufacturer, one for dry and two for wet traction. In total, every box holds 33 tyres: 22 dry traction and 11 wet traction tyres. These are all of the tyres used in the race.
Tyres must maintain the pressure recommended by the manufacturer, both to ensure the safety of the rider and to offer top performance. This year’s regulations stipulate that all wheels must be fitted with sensors. These ensure the pressure is maintained within the limits permitted (typically, 2 bars for the front and 1.8 bars for the rear tyre). Low tyre pressure results in greater contact with the asphalt but undermines the motorcycle’s stability and can make temperatures rise in excess. On the other hand, very high pressures can reduce tyre grip.
For a racing tyre to yield optimal performance, it must reach a high temperature that increases its adherence to the asphalt. Michelin stipulates that tyres must be kept in the box heaters for at least an hour, to reach a temperature of 90°C before the bike is taken to the track. That said, it also recommends heating tyres for up to two hours on some occasions. The ideal racing temperature for the front tyres is around 100°C, while 120°C or more is recommended for the back tyres.
A racing tyre consists of rubber at an extremely high temperature, spinning between a 150-kilogram vehicle and the asphalt, and, as such, it must endure considerable forces. During acceleration down a straight path, the back tyre is subjected to more than 2200 Newtons of force and, during a sudden stop, the front tyre experiences over 2500 Newtons of force. During a turn, lateral forces exceed 2000 Newtons. To get a sense of the magnitude of these forces, this is like having a weight of more than 200 kg pulling on the tyre in the direction the force is applied.
Perhaps the most amazing part of all this is the fact that the tyre’s constant contact surface is approximately the size of a two-Euro coin. In addition to supporting the motorcycle over the track, the wheel—particularly the front one—serves as a sensor for the rider. From the feeling they get from the tyre rubber, riders can tell what condition the asphalt is in and whether there’s enough grip to rev up. All of this information is gathered from this small surface the size of a coin!
Choosing the right tyre for a race is often the key to victory. It is no accident tyres are considered one of the most important elements of the sport. Marc Márquez and Dani Pedrosa know this well!