French GP: Yamaha preview

Round: 4 Date: May 19 Circuit: Le Mans Country: France Track length: 4305 m Opened: 1965 Fastest Lap Ever: 1' 38.421 (Max Biaggi, 2001 - MotoGP) MotoGP lap record: 1' 39.954 (Max Biaggi, 2001) Last year MotoGP winner: Max Biaggi MotoGP 250 lap ...

Round: 4
Date: May 19
Circuit: Le Mans
Country: France
Track length: 4305 m
Opened: 1965
Fastest Lap Ever: 1' 38.421 (Max Biaggi, 2001 - MotoGP)
MotoGP lap record: 1' 39.954 (Max Biaggi, 2001)
Last year MotoGP winner: Max Biaggi
MotoGP 250 lap record: 1' 41.447 (Daijiro Katoh, 2001)
Last year MotoGP 250 winner: Daijiro Katoh

2001 Race summary
Le Mans was the first of many highlights for the Marlboro Yamaha team in 2001, which destroyed the competition at the French circuit with a perfect one/two team performance. After a textbook start by Max Biaggi and Carlos Checa, the Marlboro Yamaha teammates went on to leave the field in their wake, finishing first and second, respectively, by nearly five seconds over third placed Valentino Rossi (Honda). The result placed Biaggi third in the championship with 54 points -- behind Norick Abe (Antena 3 Yamaha d'Antin, 57pts) and championship points leader Rossi (91pts).

From the green it was Kenny Roberts (Suzuki) who led the field into turn one for the first time, but the American could only hold off a determined Biaggi until lap four. The Italian then went on to build a comfortable buffer within only a handful of laps before out-braking himself into the back chicane. The Italian kept it upright but the mistake relegated him back to third, behind Checa and Roberts. It was only a lap later that Checa made his move and took the lead into the first hairpin to carry on from where Biaggi had left off. But Biaggi was far from finished, and on lap ten he moved into second before sizing up the No.7 YZR500 to take the lead for the second time, and eventually the win by 3.266 seconds. Abe came through from a poor start to take fourth place, consistently setting some of the fastest laps in the process.

Set-up report YZR-M1
Of all the circuits on the MotoGP World Championship calendar Le Mans doesn' t cause too many headaches for the chassis engineers due to a somewhat dated stop/go design. It's a circuit made up of a number of first or second gear hairpins linked together by a series of long straights, with only the occasional chicane breaking up the run to the next hairpin. With almost every straight running into a low speed hairpin, and turns three and five the most likely passing points, all efforts will be focused towards finding stability under brakes. The YZR-M1 therefore requires, as it did in Jerez the round before, a firm front end to deal with the aggressive weight transfer, while still providing the ability to soak up any bumps entering each of the slower turns. It is likely the compression damping rates will be slightly firmer than at Jerez, while the rebound will be dialed in to offer a more controlled return of the fork's full length. This will be done in an effort to offer stability as the rider makes the somewhat aggressive transition from the brakes to the throttle.

Fork spring rates will be the highest used anywhere during the year to cope with the extreme braking forces and to control the pitching, while the bike' s attitude will be set to ensure stability on the rear end. This is achieved with a lower rear ride-height, lowering the center of gravity, in turn helping to prevent the rear tyre from rising off the track's surface and then attempting to slide past the front.

It's a chassis balance that will affect the cornering characteristics by reducing its turn-in agility and cornering capabilities, but it's an acceptable compromise at this track. Experience has shown, as it did last year with the YZR500, the gains made up under brakes far outweigh those that can be made while in the slow speed hairpins themselves.

For this very reason the two-day test held in Mugello, after the MotoGP of Jerez, was intended to further develop the YZR-M1's electronically-controlled engine braking system, but bad weather prevented the team from making any real progress. The target was to control the effects of the engine braking more precisely to improve stability, while also adjusting the chassis set-up to further reduce the pitching effect at the same point on the circuit. These parts will now need to be tested during practice at the Le Mans MotoGP.

Meanwhile drive must not be neglected; but with the rear ride-height reduced for stability entering the turns the ability to hold the line while exiting a corner will be compromised. Therefore a softer rear spring rate will feature on the M1 for good predictable feedback, but it will be dialed in with a high degree of preload to prevent the rear-end from squatting under power as the weight transfers to the back of the bike. Too much weight transfer will make it hard to hold the racing line under power and will also increase the likelihood of the M1 wheelieing off the turns.

Set-up report YZR500
The YZR500 shares a similar story with the M1 in relation to the chassis set-up, but due to the circuit's layout this will be one of the two-stroke's strongest opportunities at a good result thanks to their lighter minimum weight which offers an advantage in braking performance.

But where the four-strokes will be strong is driving off the slow speed turns; therefore rear wheel drive will become more important than in the past for the two-strokes. To help the two-strokes get on the power early the rear linkage and suspension unit will be tuned to offer ample rear-end feedback. This will come via a more progressive linkage system, lower rear spring-rate than the more powerful four-strokes, and slightly softer damping characteristics. It will also help prevent the rear tyre from being overworked as quickly as the four-strokes, but it is a fine line between feel and drive.

The Le Mans surface tends to offer a reasonable amount of grip, although, changes in temperature can have an extreme affect on tyre life; for this very reason tyre compounds will be difficult to predict until race day. And as for issue regarding 16.5 verses 17.0inch rear rim sizes, it is possible that the starting grid will have a mixture of both but the former will be more popular. With very little time spent working the side of the tyre both sizes have benefits at Le Mans.

Since the run between each hairpin is basically a drag race, Yamaha technicians will sacrifice a little bottom end power in an effort to gain the upper hand in top speed over the newer machines. Even so predictability in the delivery is always a must, as the exit speed greatly influences the eventual top speed at the end of the straight.

-yamaha-

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About this article
Series MotoGP
Drivers Max Biaggi , Valentino Rossi , Norifumi Abe , Kenny Roberts Jr. , Daijiro Kato