Set-up report Assen Round 7

Setup

ROUND: 7, DUTCH GRAND PRIX
June 28, 2003
Circuit: Assen
Country: Netherlands
Track length: 6027 m
Opened: 1955
Fastest Lap Ever: 2' 0.973 (Valentino Rossi, 2002 - MotoGP)
MotoGP lap record: 2' 0.973 (Valentino Rossi, 2002) 
Last year MotoGP winner: Valentino Rossi
GP250 lap record: 2' 4.824 (Roberto Rolfo, 2002)
Last year GP250 winner: Marco Melandri 
Circuit tel: +31 592 321321
Circuit web site: http://www.tt-assen.com

2002 MotoGP race summary
The 2002 Assen TT became a race of attrition with six out of the 21 starters never seeing the finish of the main event, and another handful returning to the fray after running off the track at some point during the race. Carlos Checa (Yamaha) was one of the battle-scared survivors to take home a valuable bag full of points; moving up to third in the championship points' race as a result. The Spaniard finished a creditable third aboard the YZR-M1 after a last lap, last corner collision with eventual fifth place finisher Tohru Ukawa (Honda).

With only the final chicane remaining Ukawa made an attempt to slip up the inside of Checa, a move that saw the two riders collide, bouncing the YZR-M1 off the track and into the dirt. Checa managed to stay upright in the slippery conditions, rejoining the race, while Ukawa crashed only meters from the chequered flag. The latter remounted his damaged machine to limp across the line some 29 seconds behind fourth placed man Max Biaggi on the second factory Yamaha four-stroke.

Valentino Rossi (Honda) put in yet another dominating performance to take his sixth win of the season, but only after challenging the aggression of long-time race leader Alex Barros (Honda). The Brazilian rider came through from the back of an eight man pack to take the lead on lap three, and never relinquished his hold until lap 16 – finishing 2.233 seconds behind the Italian.

Set-up report YZR-M1
Assen is unique in a number of ways; the Dutch TT originally began life as 28km street circuit before being shortened – once in 1955 and again in 1984 – to comply with the ever-changing demands of modern motorcycle racing. The most recent of these took place during the 2001 winter break with the modification of the paddock hairpin. Even so the Assen layout is still the longest on the MotoGP calendar, measuring over six kilometers in length, and continues to maintain its street pedigree, giving it a character all its own. Although not every rider found the latest changes to their liking, feeling that the so-called back ‘straight’ lost some of its flowing character, it is still a popular addition to the MotoGP calendar.

With barely a straight piece of tarmac in sight there is no rest for the MotoGP field, making Assen more of a rider’s circuit than any other ever visited this season. Handling will therefore be a major focal point, due to high-speed chicanes and dramatic camber changes – the latter, in some places, resembling the profile of a public road more than that of a motorcycle racetrack. This single feature in itself makes Assen a challenging circuit to master. Hold the inside line and the rider will benefit from the extra drive available off the steeper section of the camber, but the suspension will need to compensate for these much higher G-force loads.

A good result at Assen relies heavily on a chassis that offers both agility and stability. It is quite a difficult balance to find at the best of times. This is why Yamaha will continue with the base geometry it has used over the past few rounds, relying on the finer adjustments of the suspension package and the correct tyre profiles to get the best out of the Deltabox chassis.

The combination of such fast cornering, good grip levels and extreme camber angles produce the high cornering G-forces, a load which the suspension package will need to deal with. For this reason a heavier rear spring rate will be chosen, in comparison to the front set-up, to prevent the back of the bike squatting under power, yet it will still need to offer a compliant ride to ensure feel isn’t compromised. Feel won’t be compromised if the compression damping character is dialed in to compensate. Therefore it will be wound back, from what was used in Barcelona two-weeks earlier, increasing the predictability of a slide as well as tyre life.

Although the rear spring rate is firmer than what Yamaha used at a circuit like Mugello, the front will be somewhat softer in feel. The latter is possible because of the lack of hard braking that will be done on the flowing layout, as trail braking into the apex is the only way to a good TT laptime.

With an outright top speed of around 300kmh Assen isn’t the fastest circuit, especially when you compare it to the 330kmh plus of Mugello. But the Dutch TT isn’t about outright top speeds, rather the key is a top speed average. In this regard Assen is one of the fastest tracks of the year. Because of this it’s an extreme and hard working circuit, not only for the riders and the chassis, but the tyres too. Fortunately grip levels are high yet the track surface isn’t too abrasive, even though almost all the driving will be done off the side of the tyres.