WRC

Cyprus Rally: Michelin preview

The Mediterranean Trilogy, Episode 1: Michelin on the isle of Aphrodite As competitors prepare to tackle the Rallies of Cyprus, Turkey and Greece, the 2005 World Championship calendars kicks off a sequence of three rounds marked by rough, ...

The Mediterranean Trilogy, Episode 1: Michelin on the isle of Aphrodite As competitors prepare to tackle the Rallies of Cyprus, Turkey and Greece, the 2005 World Championship calendars kicks off a sequence of three rounds marked by rough, hard-wearing conditions. These three events also tend to take place in very hot weather which only adds to the punishing challenge for the drivers, mechanicals and tyres alike. Last year, Sébastien Loeb and the Citroën-Michelin triumphed in two of the Mediterranean Trilogy's ports of call, including Cyprus.

The Cyprus Rally first appeared on the world calendar in 2000 as an emergency stand-in for the originally scheduled Rally of China. That year, competing in the lofty Troodos Mountains renowned for their asbestos mines, the drivers got their first taste of the event's slow, twisty, stone-littered stages and Ford Focus-Michelin's Carlos Sainz won at an average speed of just 60 kph!

"This year, the Cypriot round marks the beginning of a series of three particularly rough rounds and a good run by any one team over the next month and a half could well have an important bearing on the outcome of the title chase at the end of the year. Cyprus, Turkey and Greece follow on from each other in such quick succession that they leave little scope to fine-tune tyre specifications from one event to the next," says Michelin Competition's Rallies Manager Aimé Chatard. "Three rallies in a row on such similar types of terrain is not easy either for tyre manufacturers as far as development and production are concerned.

Over the 27 working days between May 4th and June 7th, we will have to produce the tyres for a quarter of the championship, Cyprus, Turkey, Greece and Argentina!"

20 international events in the space of two months! In addition to attempting to win on all fronts, Michelin, which is present in all motor sport's leading disciplines, faces a particularly stimulating challenge from the beginning of May until the end of June: the mass production of competition tyres. During this period, the firm's tyres will effectively compete in five F1 Grands Prix, four WRC rallies, four MotoGP races, two Rally-Raids, four rounds of the FIA GT and WTCC series and the Le Mans 24 Hours!*

There are naturally a number of challenges within this overall challenge, including catering for the stages of Rally Cyprus which figure amongst the toughest on tyres of the entire World Championship.

"The roads are twisty and the drivers are forever re-accelerating in 1st, 2nd and 3rd gears which produces wheelspin and therefore wear. Active differentials and traction control systems help combat this phenomenon but it's above all up to the driver to control wheelspin and manage the wear of his tyres," points out Aimé Chatard. "We have to find the best performance/wear ratio for these hard-wearing rallies."

Michelin runners will this year benefit from the latest Michelin Z BTO tyre which has already proved its worth over New Zealand's flowing, medium-wearing stages as well as over the twistier but less aggressive gravel tracks of Sardinia. In Cyprus, where its task stands to be complicated by searing heat, this new product will need to perform on twisty, hard-wearing stages and the hard compound Michelin Z BTO is expected to be the most frequently chosen option over the weekend. *

Michelin's 2005 record up to May 8th includes 5 F1 Grand Prix wins (with Renault, McLaren- Mercedes), 3 WRC wins (Citroën), 2 MotoGP wins (Yamaha, Honda), 3 FIA GT wins (Ferrari, Porsche), 3 Rally-Raid wins (Mitsubishi, Volkswagen) and 7 consecutive wins at Le Mans since 1998.

TYRES, DRIVERS & WHEELSPIN

The Cyprus Rally places the accent for once on coping with the effects of low speeds instead of high speeds! The drivers are not accustomed to competing at such a slow pace and instinctively tend to accelerate to gain time. However, when running in 1st, 2nd and 3rd gears, they quickly reach maximum engine torque which not only favours wheelspin and wear but also consumes a great deal of energy in comparison with the distance actually covered.

"The active differentials and traction control systems used by modern WRC cars help minimise the phenomenon, but Cyprus represents something of a dilemma," confesses Ford-Michelin's Technical Director Christian Loriaux. "You need a very agile car, which implies very slack differentials. But you also need a lot of traction and, for that, you want tight differentials. In our bid to combat wheelspin, we have seen that trying to limit it mechanically does not result a big time gain, so we leave it up to our drivers to manage the wear of their tyres themselves."

"You need wheelspin to move forward," says Sébastien Loeb's engineer Didier Clément. "There is an optimum level of wheelspin below which the car doesn't go quickly enough and above which the constraints are considerable. If the driver accelerates too hard, his car will oversteer and end up in the soft gravel. The drivers have therefore learnt to measure the way they press on the right-hand pedal to enable them remain in the clear lines. Meanwhile, we have put a great deal of work into the flexibility of the engine."

In conclusion, even in the 21st Century, the driver remains the only judge when it comes to adapting the way he drives as a function of the feedback he gets via the steering wheel. And, sometimes, that can be to the detriment of tyre wear.

ON THE TECHNICAL FRONT: 2 PATTERNS AUTHORISED, 1 PATTERN CHOSEN -- IN 2 DIMENSIONS

The rules permit two types of tread pattern for the Cyprus Rally but, as for the first three loose surface encounters of 2005, Michelin runners have chosen just one pattern: the Michelin Z. However, they will be able to choose between two dimensions: the familiar 17/65x15 tyre and a wider option (19/65x15). A maximum of 40 tyres from each driver's individual quota of 65 may be used.

MICHELIN Z BTO

The Michelin Z BTO, which won in New Zealand and Sardinia, has also been chosen for Cyprus. Given the high temperatures and the hard-wearing nature of the stages, the hard compound Michelin Z BTO tyre could well prove decisive.

NO TESTING IN CYPRUS The Cyprus Rally is considered as a non-European round which means that on-site testing is not permitted. As in Mexico and New Zealand, the event represents something of an unknown therefore for Michelin's technicians and runners. However, they will be able to count on the experience of their previous visits to the island as well as on the result of testing work in Spain, Greece and Italy.

HARD-WEARING FAMILY Along with Turkey and Greece, the Cyprus Rally is one of the hard-wearing family of rallies. For Michelin, the World Championship qualifying rounds fall into one of six categories: wintry asphalt, ice/snow, asphalt (wet and dry), hard-wearing gravel, medium-wearing gravel (Mexico, New Zealand, Great Britain) and low-wearing gravel (Italy, Argentina, Finland, Japan).

FROM THE MICHELIN 'GW' TO THE 'Z BTO'

In 2002, Michelin launched the GW tyre in Cyprus and Marcus Grönholm (Peugeot-Michelin) won with it out of the box over the island's punishing, hard-wearing stages. Last year's Acropolis Rally saw Michelin introduce its new TDE tyre (Taux d' Entaillement Evolutif) which was also developed for hard-wearing terrain. However, the weather conditions did not favour its use. These two products have enabled Michelin's engineers to build up a better understanding of the demands made of tyres on hard ground and that has ultimately led to the new BTO version of the Z tyre which celebrated its launch with victory in New Zealand last April.

MORE THAN 100°C

It's not only the drivers who suffer from the heat in Cyprus. Ground temperatures can soar as high as 50°C and tyre temperatures can exceed 100°C during stages.

A GREATER DISTANCE TO COVER

Although active differentials help minimise wheelspin, the Cypriot stages are so slow and twisty that this phenomenon can still reach 150%. In the first group of stages, which total 60.89 km, tyres could therefore cover the equivalent of more than 90 km!

-michelin-

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About this article
Series WRC
Drivers Carlos Sainz , Marcus Gronholm , Sébastien Loeb , Christian Loriaux , Didier Clément
Teams Citroën World Rally Team