MotoGP Set-up report - Assen, The Netherlands

Assen, The Netherlands
20/6/2005

Round 7: Assen, The Netherlands
Track length: 5997 m
Opened: 1955
Fastest Lap Ever: 1' 58.758 (Valentino Rossi, 2004)
MotoGP lap record: 1' 59.472 (Valentino Rossi, 2004)
Last year MotoGP winner: Valentino Rossi
Circuit web site: http://www.tt-assen.com

2004 MotoGP Race Summary

Yamaha rider and reigning World Champion Valentino Rossi once more demonstrated
his full repertoire of race-craft by winning his third race in a row, at the
2004 Assen TT, after a last lap of epic skill and determination. A further
showing of the significant improvements made to the YZR-M1 were evident when
Yamaha Tech 3 pilot Marco Melandri also secured his second consecutive podium
result - taking third behind second place rider Sete Gibernau (Honda).

Rossi was involved in a race-long contest with Gibernau. With the others unable
to match their lap record breaking pace, they eventually left a nine-second gap
back to Melandri at the flag. Rossi's desire to win his third race in a row, and
his fourth with Yamaha saw him set the new lap record on lap 18 of the 19, with
a time of 1'59.472s. That lap brought him close enough to dive inside Gibernau
on the brakes at turn 12. The pair made contact into the following double
right-hander as Rossi almost lost the front, leaving the chasing Gibernau
nowhere to go and nursing a broken front mudguard.

2005 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 this year with the modification to the snaking back
straight leading up to the Stekkenwal right hander. With speeds increasing
safety became an issue with the current layout and as a result the former back
straight has now been fitted with a second gear right hander at the midpoint
followed by a sweeping left into Stekkenwal.

In addition the De Bult turn has been become more of a 90-degree turn and has
lost its positive camber. Despite these changes the Assen layout is still the
longest on the MotoGP calendar, now measuring just less than six kilometers in
length, and continues to maintain its street pedigree - although this is
changing with every modification. The length has been shortened by a total of
30m - from 6027 to 5997 - and is due for an additional modification in 2006.

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 that will be experienced.

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, but
with the white line to white line racing line it is a must find. 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. This won't be an issue 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 seriously hard braking that will be done on the flowing
layout. Tailing the brakes into the turn is more common at this circuit.

With an outright top speed of around 310kmh Assen isn't the fastest circuit,
especially when you compare it to the 340kmh plus of Mugello, but that doesn't
matter as the Dutch TT isn't about outright top speeds - it's the top speed
average that counts. 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.