The TT Circuit Assen is a motorsportrace track built in 1955 and located in Assen, Netherlands. Host of the Dutch TT, it is popularly referred to as “The Cathedral” of motorcycling by the fans of the sport. The venue holds the record for being the only circuit to have hosted a Grand Prix motorcycle event every year since the series was created in 1949.
It has a capacity of 110,000 spectators, including 60,000 seats. Since 1992, the circuit has also been part of the Superbike World Championship calendar.
The original Assen track was first used for the 1925 Dutch TT (Tourist Trophy) race, held on country roads through the villages of Borger, Schoonloo and Grolloo, and organized by the Motorclub Assen en Omstreken. The brick-paved track had a length of 28.57 km (17.75 mi). The winner was Piet van Wijngaarden on a 500 cc Norton with an average speed of 91.4 km/h (56.8 mph). In years afterwards the Dutch TT was held on a street circuit through De Haar, Barteldsbocht, Oude Tol, Hooghalen, Laaghalen and Laaghalerveen.
In 1951 the Italian Umberto Masetti took the record on a 500 cc Gilera with an average speed of 162.35 km/h (100.88 mph). In 1954, Geoff Duke of Great Britain reached 170.69 km/h (106.06 mph). The circuit remained unchanged until 1955, when a whole new circuit was built close to the site of the original, but less than a third of the length and much more like a modern road racing circuit.
In the period of 1999-2002, the circuit invested millions in upgrades. In 1999, the circuit management placed a new main grandstand and hospitality buildings. In 2000, a new Race Control tower was built, as well as 34 newly equipped pit boxes, a new media and medical centre. Between September 2001 and April 2002, another 9 million Euro’s is spent on the enlargement of the paddock area from 40 to 60.000 square metres. This upgrade meant that the Veenslang and Ruskenhoek corners had to be altered. The main straight has also moved about 50 metres eastwards and a new two-lane tunnel now connects the paddock with the main entrance road and the media accreditation / welcome centre. The Mandeveen and Duikersloot corners have been moved back by 10 metres to accommodate larger run-offs and gravel beds at the southern part of the circuit. That part of the track has also been resurfaced with new asphalt. In total, the circuit has been shortened from 6.049 to 6.027 metres. The total amount of costs on these upgrades is 23 million Euro’s.
In 2005, the grandstand at the Geert Timmer corner was slightly altered. In order to improve the gravel run-off length, the grandstand was made in a ‘floating’ manner to accommodate the extra space that was needed. The lay-out of the circuit was also slightly altered.
The circuit was fundamentally redesigned again in 2006, becoming the so-called A-Style Assen TT Circuit. All alterations aside, only one section of the circuit is original; the finish line never moved. On 21 September 2009 it was announced that a new chicane will be added, after a request from the A1GP organization, however A1GP was unable to start the 2009–2010 season and as a substitute the Superleague Formula replaced A1GP.