Part of the perennial success and popularity of the Assen event is its ability to modernise its facilities and layout without losing one iota of its unique character and appeal, to riders and fans alike.

Starting out its racing life as a 28km street circuit it was shortened in 1955 and then again in 1984, when it was also widened somewhat.

In many ways Assen is the granddaddy of the contemporary MotoGP circuits and is the longest still in current use, at 6.027km. With 23 distinct corners and many more subtle changes of direction and lean angle in between, it is possibly the most cerebral of challenges for riders and teams.

Despite the rapid, flowing corners and high average lap speed, outright power is not necessarily the determining factor at Assen. A good power output and a linear throttle response are nonetheless essential ingredients to the set-up mix but camber is King at Assen, a circuit that mimics the characteristics of a real road more than any on the current MotoGP calendar.

With a pronounced crown on the 'road,' the high speed switchbacks of much of the Assen circuit mean that camber goes from positive to negative to positive again as each corner is dealt with.

This unique characteristic of Assen demands not only judicious throttle control from the rider when crossing the cambers but suspension capable of dealing with its ever changing characteristics, not to mention a chassis package with a useable blend of good stability and high speed agility.

To prevent the rear end squatting under the combined forces of positive camber and acceleration, a higher rating of rear spring will be required for Assen, altering the usual front to rear balance of the M1. To handle the tarmac ripples and bumps, and because there are few places where heavy braking is called for, the front forks can be left on a softer setting than the rear.

One relatively recent piece of track modification has added another complication to the set-up. The double apex corner of Duikersloot, tightened and brought inwards to improve run off in the event of a crash two years ago, now has a largely flat camber, a fact which can catch out riders who forget that they have had the help of a positive camber at most other corners of the circuit.

Tyre performance is another key at Assen. The cambers aid outright grip in most instances and with the tarmac being grippy but not overly abrasive Assen is not the hardest circuit on tyres per se.

The front tyre is particularly important, however, such are the frequently encountered fast corner entries. Braking has frequently to be performed right up to the apex of the turn to attenuate speed, rather than violently reduce it, maintaining valuable momentum and machine balance.



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