TT Circuit Assen was opened as a permanent racetrack in 1955, since when it has been modified and adapted several times. The northern loop was removed in 2006, reducing the length of the circuit from 7.705 kilometres to the 4.555 kilometres it is today. The circuit in the Dutch province of Drente is technically demanding. While the first section is relatively slow, the second section is where the fun really starts, with some very fast sections. The corners are slightly banked and the longest straight is 960 metres long.
“Like Misano, Assen was designed for motorcycle racing. The kerbs are flat, placing relatively little demand on the construction of the Hankook race tyre. In contrast, the running surface of the Ventus Race is put under greater strain when accelerating out of corners in the winding sections, some of which are very narrow,” explains Thomas Baltes, the Hankook race engineer responsible for the DTM.
Last time out, at the Norisring, the increase in power of the current crop of DTM cars, with turbo engines generating in excess of 600 hp, again put greater strain on the Hankook race tyre than in previous years. Thomas Baltes: “The surface of the track at the street circuit in Nuremberg, which is usually used by everyday traffic, is far from as aggressive and demanding on the tyres as the asphalt of a thoroughbred racetrack. Despite this, the constant acceleration and wheelspin caused greater wear than we have been used to at the Norisring, particularly on the rear axle.”
The driver’s driving style and tyre management will be important factors in Assen. However, the position in the field also plays a major role in this regard. “When a driver is able to drive his own race out in front, like René Rast and Bruno Spengler at the Norisring, they can obviously manage their tyres differently to a driver who is involved in battles for positions. Mike Rockenfeller came through from eleventh on the grid to finish third in race two at the Norisring and really put the Hankook race tyre to the test for the full distance. However, that kind of tactic is not necessarily advisable on aggressive asphalt like you find in Assen,” said Hankook’s head DTM race engineer.
Baltes believes the strain on the tyres at TT Circuit Assen will be average compared to many other DTM circuits. “With the layout of the circuit in Assen, the teams can use the set-up to get even more out of the Hankook race tyre. At the Norisring, the key was braking and accelerating. In Assen, the banked corners and fast passages in the second part of the track mean the car set-up will play a decisive role in the race for victory.”