Czech GP: Michelin preview

BACK TO WORK AT BRNO Sunday's Czech Grand Prix brings the 2002 MotoGP World Championship back to life after a much-needed, four-week midseason break. This year has been more gruelling than most for many MotoGP riders and teams, because the new...

BACK TO WORK AT BRNO

Sunday's Czech Grand Prix brings the 2002 MotoGP World Championship back to life after a much-needed, four-week midseason break. This year has been more gruelling than most for many MotoGP riders and teams, because the new MotoGP four-strokes are still in their development phase, requiring plenty of testing and development.

Nonetheless, four-strokes have ruled all eight rounds so far, World Championship leader and 2001 Brno victor Valentino Rossi (Repsol Honda Team RC211V-Michelin) winning seven races, his team-mate Tohru Ukawa (Repsol Honda Team RC211V-Michelin) taking the other victory. The 500 two-strokes have enjoyed only a few brief moments of glory, Olivier Jacque (Gauloises Yamaha Tech 3 YZR500-Michelin) taking the only 500 pole of the year at last month's German GP. The Frenchman might've gone on to win that race if he hadn't been knocked out of contention, but it's likely that the four-strokes will rule once again at Brno, which should really suit their performance character.

Two-stroke or four-stroke, Michelin riders have dominated every stage of the MotoGP series, with eight pole positions, eight race victories and eight lap records from the eight GPs. Michelin men also currently hold the top eight places in the championship and have a great record at Brno, with six wins from the last six premier-class Czech GPs.

Just one race remains in Europe after Brno before Grand Prix racing leaves Europe for five weeks, taking in races in Brazil, Japan, Malaysia and Australia before returning to the Continent for the season-ending Valencia GP on November 3.

THE RIDERS AND BRNO

The Brno racetrack holds a mixed bag of memories for Max Biaggi (Marlboro Yamaha Team YZR-M1-Michelin). The Italian superstar has won six GPs at the circuit, including the 1998 and 2000 Czech 500 GPs, but he tumbled out of last year's race, the beginning of the end of his challenge for the last-ever 500 World Championship.

This weekend Biaggi returns to Brno on ever-improving form, his M1 four-stroke now within reach of its first success in the new MotoGP class. And if the former 250 World Champion isn't really in the hunt for this year's MotoGP world title, he's determined to prove to the world that he's still very much a winner.

Biaggi has always gone well at Brno because the sweeping nature of the circuit suits his artful, inch-perfect riding style. The Czech track is wider than most, and Biaggi's ability to cut the fastest line every lap gives him a real advantage here. The undulating venue also features many downhill, adverse-camber corner entries, through which mastery of the front end is all, and Biaggi is a front-end genius.

"Brno is very wide," he agrees. "So you can use a lot of different lines, it's up to the rider to use the best line every lap, depending on the situation, which makes it really interesting to ride. Machine set-up is very important wherever you go, but you need to work especially hard at choosing the correct front-tyre compound for this race, front-end grip is so important here because there are so many off-camber corners."

A month before last year's Czech GP Biaggi tested at the track along with team-mate Carlos Checa (Marlboro Yamaha Team YZR-M1-Michelin), who obliterated the existing track record riding a development version of the M1. Checa's pace announced that the new breed of MotoGP four-strokes would be incredibly fast. But during last August's Czech GP, Biaggi and Rossi were just as quick, bettering the 2000 race time by more than half a minute! Their stunning pace on their 500s revealed that as much of Checa's speed during those tests was down to Michelin's latest 16.5in rear slick as to the awesome speed of his big-bore four-stroke.

So far this year Biaggi has been able to run softer compound rear tyres than his main four-stroke rivals because he has a very tyre-friendly riding style. "Max's riding style is very smooth" explains Biaggi's Michelin technician Daniel Croispine. "Using soft tyres can give him an advantage, certainly early in the race. And because the engine is quite gentle on tyres, he has no problems with endurance despite running a softer compound. Max really likes the track. He's very pure in his lines, and Brno is wide and fast, so it's good for him."

Biaggi's arch-rival Rossi also appreciates Brno. He scored a vital win at last year's Czech GP after Biaggi had tumbled out of the lead while just a few metres ahead. "He was going so quick," recalls Rossi. "I was thinking, 'ah, maybe it's possible to overtake him here on the last lap', or 'here I'm faster, there I'm slower', and when he crashed I thought 'oh, now it's necessary to change my plan'. I think Brno 2001 is the masterpiece of my career because the mental situation was so difficult before the race.

"We tested at Brno in June and I think this will help us at the GP, because we have a good base to start from. During the tests we tried some new suspension links and a selection of Michelin tyres, working to improve traction and edge grip. I think we've made big steps since then, so I think we can be quite fast in the race."

MICHELIN TYRES AND BRNO

Brno is one of the faster MotoGP venues and a challenging and rewarding circuit for riders. The Czech venue is also one of the few racetracks where front-tyre choice is probably more crucial than rear-tyre choice. There are straightforward reasons for this -- Brno is laid out across wooded hillsides, with uphill and downhill sections, the downhill corners offering riders and engineers complex, negative-camber corner entries. Their task is further complicated by the track's bumpiness, which can contribute to causing chatter if riders don't work closely with their chassis, suspension and tyre engineers.

"Brno is very bumpy because the surface is quite old and they run truck races there," explains Michelin Grand Prix manager Emmanuel Fournier. "The track isn't very demanding on tyres from a compound point of view because the surface isn't so aggressive, possibly because it's old and smooth. Also, Brno is very balanced, with a fairly equal number of right-handers and left-handers (eight and six respectively), and the character is medium-gear sweeping turns, not tight, low-gear hairpins.

"But it's very important to choose the correct front tyre. Most riders tend to choose the same type of front at most races, just changing compounds according to the track, because they need to know a front tyre really well to be able to fully exploit it. But many of our riders like our latest front tyre, which has a new construction mainly for more feel. Feel is so important, especially with the front, because the more feel a rider gets, the more confident he will be, and the more confident he is, the more he'll be able to exploit the tyre's available grip."

"We've already tested twice at Brno with the four-strokes, with Yamaha last July and with Honda in June. Our rear tyre has changed a lot since last summer, I think we were using an S2 profile rear at that test, but since then we've found the best direction with the S4 profile, which we tried for the first time last November, with HRC at Jerez. The S4 immediately gave excellent traction and since then we've made big improvements in edge grip. But the developments made since we tested at Brno during June aren't night and day."

The combination of Brno's bumps and adverse camber corners can contribute to chatter -- a high-frequency vibration at the tyre contact patch -- because riders are loading up the tyres at very high lean angles. As a rider leans further and further, the bike's suspension operates less and less sufficiently, so increasingly the tyres and chassis must take on the job of the suspension.

"Brno is one of the worst tracks for chatter, but we've not had to deal with any real chatter problems with the S4," adds Fournier. "Getting rid of chatter isn't just a tyre thing, this problem comes from an interaction of the frequency of three different springs -- chassis, suspension and tyres -- and you can only tune it out by working on all three."

-michelin-

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About this article
Series MotoGP
Drivers Max Biaggi , Carlos Checa , Valentino Rossi , Tohru Ukawa
Teams Repsol Honda Team