Three weeks after the Isle of Man TT, MotoGP (where the Movistar Yamaha MotoGP team, with Rossi and Viñales, is sponsored by BMC) is getting ready to challenge its Tourist Trophy, but this time on the TT Circuit Assen. The Dutch track is the only one to have hosted races since the founding of the World Championship and will play host to the 8th appointment in the 2017 World Championship from June 23 to 25.
Dating back to 1925, the track has changed its configuration and length plenty of times. In 1992, it was at Assen that Mick Doohan's right leg risked to be amputated after he fell during a qualification lap and got trapped under his Honda but his limb was saved by Dr. Costa. He came back to win, and most of the credit went to the thumb master cylinder Brembo engineers designed especially for him where he could activate the rear brake without using a pedal.
Even though it has 18 corners, TT Circuit Assen is very drivable with lots of fast turns and only one that is tight. This track also stands out because the deceleration is lower than at others. The maximum speed doesn't go over 320 km/h but the number of fast curves guarantees the braking systems can cool down with ease.
There are very few problems at this track, but one involves weather conditions. In 2014, the MotoGP riders started off with steel brakes because of the rain, then halfway through the race the rain stopped and many changed to bikes with carbon brakes. But these brakes hadn't been warmed up enough and some of the riders complained about problems in the first few braking sections.
According to Brembo technicians, who assist 100% of the 2017 MotoGP pilots, TT Circuit Assen is only slightly demanding on the brakes. On a scale of 1 to 5, it earned a 2 on the difficulty index, a score that surpasses only that of Phillip Island.
The most demanding braking sections
Of the 10 braking sections at the TT Circuit Assen, only one is classified as demanding on the brakes, two are of medium difficulty and the remaining seven are light.
The descending right-hand braking section at the Haarbocht Curve (turn 1) is where the riders and braking systems have to work the hardest. The bikes arrive going 291 km/h and the riders brake for 3.9 seconds in a space measuring 213 meters, which is the same length as a field of 2,000 tulips. To be able to set up the curve, the riders have to reduce their speeds to 111 km/h, which means applying a load of 6.1 kg on the brake lever and undergoing a deceleration of 1.5 G. Meanwhile, the pressure created through the Brembo HTC 64T brake fluid reaches 10.6 bar.
At turn 9 (De Bult), speeds drop from 242 km/h to 112 km/h in 3.1 seconds during which the MotoGP bikes travel 130 meters. This requires applying a load of 5.7 kg and experiencing a peak deceleration of 1.4 G, which is 0.1 G more than that of the Bugatti Veyron.
Turn 6 (Ruskenhoek) on the other hand, is the only corner where the riders go over 300 km/h. To stay on the track they need to brake for 1.6 seconds, the time required to drop down to 236 km/h. As a result, the load on the lever is about 2.7 kg and the pressure doesn't exceed 4.6 bar.