Set-up report Jerez Round 3

Setup

Round: 3
Date: May 5
Circuit: Jerez Circuit
Country: Spain
Track length: 4423 m
Opened: 1985
Fastest Lap Ever: 1' 42.421 (Valentino Rossi, 2001 - MotoGP)
MotoGP lap record: 1' 43.779 (Valentino Rossi, 2001)
Last year MotoGP winner: Valentino Rossi
MotoGP 250 lap record: 1' 44.444 (Daijiro Katoh, 2001)
Last year MotoGP 250 winner: Daijiro Katoh
Circuit tel: +34 956 151100
Circuit web site: http://www.circuitodejerez.com

2001 Race Summary:
When the 2001 MotoGP World Championship moved to Europe both Norick Abe (Antena 3 Yamaha d’Antin) and Shinya Nakano (Gauloises Yamaha Tech 3) carried on with their impressive early season form to finish the Jerez MotoGP second and fourth respectively. Abe produced the perfect start and led the 22-bike field into turn one, but it was eventual race winner Valentino Rossi (Honda) who slipped through at the following right-hander. Yet the Italian couldn’t shake the YZR500 and eventually, on lap 13, Abe re-took the lead. Over the next seven laps the Japanese wild child led the race with Rossi hounding him at every turn. On lap 20, entering the final hairpin on to the front straight, the Honda rider made his move and it stuck.

Nakano looked set for his first podium finish when third placed Loris Capirossi (Honda) overshot turn one, but a hard charging Alex Crivillé (Honda), cheered on by his home crowd, made his way past the 23-year-old on lap 23 to complete the podium.

Meanwhile Marlboro Yamaha Team rider Max Biaggi was looking strong in seventh place until he ran off the bumpy Jerez circuit. The Italian rejoined the race to finish 11th while his teammate, Carlos Checa, struggled through the aftereffects of a massive qualifying crash that left him in 14th place.

Set-up report YZR-M1:
Because of the nature of Jerez, which has many hard braking areas, change of camber and an undulating layout, setting up a MotoGP machine here can be challenging for even the most experienced team. The main aim is to find a chassis set-up that works well during heavy braking – maintaining stability over the countless bumps that infest the entry into almost every turn. For 2002, though, it is likely that this latter point will not be such an issue with the track recently being resurfaced. Yet, even if it is a less than ideal surface, experience has shown that this is where a majority of the passing will occur – into turn one, turn six and setting up for turn 13 onto the front straight.

In these circumstances the front forks need to deal with the high braking loads while offering some movement when nearly fully compressed, to ensure that it is the suspension that absorbs these bumps rather than only the tyre. To cater for this the solution is to increase the spring rate, which will prevent the front of the motorcycle from diving too quickly under brakes as the weight transfers forward. This step, along with reducing the ride-height geometry, will ensure the rear of the machine stays planted on the ground, in turn improving braking stability.

As for the fork compression damping, it will be set to allow enough high-speed movement to deal with the repetitive bumps, while fork rebound on the other hand is dialed in to slow the return of the forks to their full length. This will help prevent understeer as the rider makes the transition from brakes to throttle and the weight transfers to the rear of the motorcycle. The rear spring rate, meanwhile, is set for a slightly softer overall feel with less damping – aimed at helping riders gain the best drive off the undulating corners. But the spring rate will be higher than that used by the YZR500 due to the extra power and weight of the four-stroke the suspension must deal with. This will also help reduce the effects of the YZR-M1 lofting the front wheel under power, allowing the riders to get the power down harder. If the Yamaha chassis technicians were to opt for too firm a rear end initially the times may be competitive, even faster, but as tyre-wear becomes a factor, traction and chassis stability would suffer more rapidly over race distance.

After its introduction in Suzuka, Japan, Yamaha is confident that the latest generation M1 frame will not suffer from the rear-end chatter that has been experienced by the two-stroke competition at this circuit. In addition it also offers increased pitching under brakes than the frame before it, which will be beneficial during the initial turn in when running a more stable base chassis geometry set-up. Even so this is one area that the four-strokes still need to improve compared to the two-stroke machines; for this reason Yamaha’s engineers are working on a fourth generation M1 chassis to be introduced in the not too distant future.

Also aiding the YZR-M1’s stability under brakes will be the Yamaha electronically controlled hydraulic engine-braking system, which offers the ability to control the level of engine braking in each gear. This will be especially helpful entering turn one, and the final turn onto the front straight. Meanwhile, engine wise the M1’s in-line four-cylinder, four-stroke will run a similar setup to that used in Welkom with mainly cams, exhaust and carburetor settings changing to cater for the change in altitude. Yet the power delivery itself will be left so that it delivers a strong midrange to top end.

Set-up report YZR500:
It is at this circuit that the two-strokes will offer one of the greatest challenges; with the lighter bikes likely to ride the corner entry bumps more effectively, while their minimal engine braking should prove to be beneficial too.

The more popular 16.5 inch rears tend to suit the Jerez circuit well, and for 2002 the latest four-stroke incarnation – which offers a greater contact patch than in the past via a more extreme profile – will again make an appearance on the two-stroke machines. The improved longevity and better side grip will require some modification to the geometry set-up compared to last year, not due of its increased performance, rather the different profile of the tyre. The higher rotating center diameter of the tyre will require the rear ride-height to be reduced further than before, yet the rider will need to take into consideration the effects the smaller diameter of the tyre’s edge profile will have when lent over. As the rider leans into the turn this effectively reduces the rear ride-height and therefore the geometry and handling.

Power wise the main aim is for a smooth delivery. Predictability leads to confidence, which encourages the rider to get on the power earlier. For this reason some of the YZR’s peak performance will be sacrificed to beef up the midrange and flatten out the top end of the power curve. It will offer the riders the top end overrun without a large drop in power, giving the engine more flexibility between turns.