Spa 24: Michelin preview

The Spa-Francorchamps 24 Hours Tyre strategy is crucial ! The cars and drivers in the FIA GT Championship will join battle this weekend on the legendary Belgian Spa-Francorchamps...

                              The Spa-Francorchamps 24 Hours

Tyre strategy is crucial !

The cars and drivers in the FIA GT Championship will join battle this weekend on the legendary Belgian Spa-Francorchamps circuit nestling in the foothills of the Ardennes. It is the sixth round of the 10 on the FIA GT Championship calendar, and is the longest of the year as it lasts 24 hours.

Free practice starts on Thursday 26th July followed by qualifying and the race looks like being the theatre of an exciting battle between high-powered grand touring cars such as Ferrari, Corvette and Aston Martin. There are over 50 entries and they will at be at it hammer and tongs to add the mythic Belgian event to their laurels.

Although the length of the current circuit is but half that of the original, it has kept its spirit and has a number of very tricky sections. Its layout is among the drivers' favourites and is the yardstick of their courage. This weekend will be the eighth time that the FIA GT field has raced at Spa-Francorchamps.

Michelin will supply tyres for some 20 cars. The Clermont manufacturer is out to provide them with the best possible products and services to give them a rostrum finish, while bearing in mind the large variations in temperatures than can arise at Spa. And, of course, not forgetting the rain that can turn the race upside down.

The layout track length: 6,976 kms

Matthieu Bonardel, Circuit and Rally Competitions Manager

"Spa is a very quick circuit and a real challenge for the tyres. It can induce under-steer as the tyres have a tendency to slide if the settings are optimised for the rear. So it's essential to find the right balance to make sure that the front tyres don't wear too quickly. The layout is very special with two places that require exactly the right settings and for the drivers split-second appreciation and unswerving determination: the Raidillon and Blanchimont. One puts the left-hand side of the car under load and the other the right, and both are taken at very high speeds.

Temperatures can vary enormously at Spa in addition to the rain and that's why we have to adapt the products that we supply; they have to be different from each other to cover all eventualities. We bring most of our wet tyre range." The tyres

Matthieu Bonardel, Circuit and Rally Competitions Manager

Make the right choice at the right moment

"The Spa 24 Hours is a race unlike any other. Technically speaking above all and more especially because of the weather conditions, which can vary enormously in the Ardennes. Tyre strategy is certainly more important on this circuit than on any other.

Putting on the wrong tyre at the wrong moment can lose the race for a team so the ability to make the right choice is crucial. The layout is very tough and if the tyres are not adapted degradation occurs very rapidly: there's a very quick fall-off in performance so the car has to pit again and this costs it a lot of time. All the more so, as pit stops can take up to 2m 30s, a big handicap.

Double stints

"Normally, the quantity of tyres is limited by the regulations, but at Spa there are no restrictions.

It's always tricky to find the right compromise for two stints without performance loss but that is our challenge.

Type of tyres

We'll bring our full range of rain tyres to Spa to enable us to cope with any situation.

We'll also have to keep an eye on the temperatures. For example, if the track temperature is over 20C we can run on hard rubber but under 15C this doesn't work, so it's essential to be able to choose the right tyre for the right moment.

This year we'll provide 5 types of rain tyre (in two different types of grooves) and we're not allowed to hand cut them. We'll have 4 types of slicks on hand. We're bringing long-lasting tyres because in this kind of event it's more important to think about the race itself and not about qualifying. We'll also have an ace up our sleeve, a tyre that's able to do 2 stints in good conditions! We weren't able to test it during practice at Spa but in another session it's proved both consistent and quick. Finally, we won't be trying for a compromise left/right or front/rear as the track layout doesn't require it.

In GT2, we'll bring 3 types of slick tyres, 2 rain compounds and 1 intermediate. Unlike in GT1, if it rains the GT2s will spend 2 hours out on the track, so we have to supply a polyvalent compound that can hold out for 2 hours and cope with the different track conditions. That too is a very interesting challenge!"

Experience

"The fact of having double-stinted at Le Mans in good conditions augurs well for the Spa 24 Hours. But where the rain tyres are concerned our Sarthe experience will be of little use, as the choice for the Belgian circuit will have nothing in common with Le Mans because Spa is much harder on rubber. Nevertheless, the teams were able to get used to our various rain tyres during the test session on the Spa circuit at the beginning of the July. We were not able to do endurance tests in the dry so that remains an unknown factor.

The special feature of this event is that the teams go back to their first race set-up with no weight handicap. Points are awarded after 6, 12 and 24 hours. With 3 races in one, the tyres choices are even more difficult. During the first 6 hours, teams will have to look for overall performance. Then, for those still racing, to be as consistent as possible will be the new challenge, in order to reach the 12, then the 24 hours marks.

At Spa being the quickest on the track is not necessarily the most important thing: you have to stay on it! You also have to keep pit stops to the minimum as they cost a lot of time. Add the uncertainty of the weather to this and you have all the ingredients required for a very exciting race!"

-credit: michelin

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Series Endurance , Blancpain Sprint