MotoGP | Brembo, the United States GP from a brake point of view

After South America, MotoGP lands in North America for the 3rd round of the 2017 World Championship, scheduled for 21 to 23 April at the Circuit of the Americas (Austin, Texas). Designed by the German architect Hermann Tilke, it is one of the few circuits in the world to host the MotoGP and Formula 1 championships: the lap time of single-seaters is half a minute shorter than that of motorbikes. Some sections of the track take inspiration from famous corners of historic tracks. The Texan track stands out for the impressive inclination of the straight that leads to the first left turn: in total there is a difference in altitude of 41 meters between the lowest and highest point of the track, with easily imaginable consequences for drivers who make a mistake braking on downhill sections.

The Austin track is considered to be medium demanding for the braking systems. According to the Brembo technicians who assist all the MotoGP riders, the Circuit of the Americas deserved a score of 3, on a scale of 1 to 5. The Losail and Termas de Rio Hondo tracks also obtained the same value but in Jerez , where it will be raced in two weeks, the value is 4. Despite not being the longest track in the World Championship, the Circuit of the Americas is the one with the most braking points per lap: 13, a value equaled only by the Qatar GP.

But while in Losail the drivers used the brakes 37 seconds per lap, in Austin they did so for 38 seconds, double the time of use at Sachsenring. The presence of 5 curves in which the drivers change direction by braking just long enough to lose 30 km/h of speed reduces the average deceleration per lap: in these curves the deceleration fluctuates between 0,4 g and 0,6 g and this explains the 0,92 .11 g on average, the lowest value in the championship. Adding all the forces exerted by a rider on the Brembo brake lever from the start to the checkered flag, the value exceeds 13 quintals: in practice, every minute a rider is required to exert an effort of half a quintal, higher than that sustained by Superbike riders. In MotoGP, in fact, riders can use carbon discs which are also thicker than the steel discs of the Superbike. Of the 3 braking sections at the Circuit of the Americas, 2 are classified as demanding on the brakes, 8 of medium difficulty; while the remaining 12 have a slight impact on the braking systems. The hardest of all is the one at turn 339: the bikes reach 6,3 km/h and brake for 67 seconds to go down to XNUMX km/h.

The 322 meters of braking constitute the record for the entire World Championship and involve a deceleration of 1,5 g. In the first corner after the finish line, however, the load on the Brembo brake pump lever is higher (6,7 kg compared to 6,6 kg in turn 12) and the pressure of the Brembo HTC 64T brake fluid reaches 11,6 bar, that is almost 6 times the pressure of a can of 7UP. However, the bikes begin to brake at a lower speed, 297 km/h, and continue to act on the Brembo aluminum calipers for 5,2 seconds.

Even at turn 11 the load on the lever is 6,6 kg but the braking is less than 200 meters and the deceleration is 1,4 g. However, a value 0,18 g higher than the deceleration of a Porsche 911 GT3 RS 4.0 from 100 to 0 km/h.

Photo: A. Farinelli