The pressure is on for tyres
Since its debut on the rally-raid scene in 1972, BFGoodrich has emerged as the discipline's benchmark tyre brand. Its record today boasts eight Dakar wins since 1999 and it has just won the Cross-Country Rally World Cup for the 10th time. BFGoodrich has every intention of defending and developing its domination thanks to the strong relationships it enjoys with the different teams involved. The 2008 Euromilhoes Dakar starts on January 5 and the two track days organised recently near Ales, France, in association with Mitsubishi -- and attended by Luc Alphand and Nani Roma -- provided a first class opportunity to take a look at the vital role tyres play in off-road competition.
The tyre regulations for priority rallyraid drivers are very simple: a single type of tyre must be chosen for the entire season. In the case of BFGoodrich, that tyre is the Rock T/A which features a hard compound and a single pattern which ensure outstanding performance, even in extreme conditions. "It is this paradox which is the challenge we face in rallyraids," explains Michel Maraval, rallyraid tyre designer at BFGoodrich. "The different events run on very different and very challenging types of terrain, yet the teams can only use one type of tyre. Our work therefore consists in producing a versatile product which is competitive not only on smooth surfaces but also over rough and even very rough ground."
"Given the crucial role tyres play in rally-raids," continues Luc Alphand, "working with BFGoodrich is a big plus. The products we use need to be very durable and also offer the best possible resistance to punctures. Compared with the WRC, the constraints tyres face are very different, since rally-raid stages are much longer and often far more extreme."
"It's all about finding the ideal compromise," points out BFGoodrich rally-raid technician Dominique Bravy. "You very rarely get uniform conditions for stages of up to maybe 400km, day after day. To take rocky tracks in their stride, tyres need to be very strong and, to help ward off punctures, their construction features materials which ensure they don't deform. The problem is different over dunes because you want the tyres to dig into the sand as little as possible. Endurance is also a key factor, and tyre pressures are a major parameter when it comes to making sure the competitive potential of our products is optimised."
"Different tyre pressures can have a radical effect on handling," says Michel Maraval. "For rough ground, the pressure needs to be high to enable the tyres to soak up the constraints of the terrain, as well as when the car lands after a jump, which can sometimes be on just one wheel. On the other hand, soft, sandier surfaces call for low pressures to optimise traction and prevent the wheel from digging in. The aim is to compact the sand as much as possible under the wheels. The bigger the contact patch the better the result. Running with the correct tyre pressures is not only vital but it is also a key tactical consideration for the competitors. It's all about strategy: either the crew takes the time to stop and adjust its tyre pressures if the terrain changes or else they don't stop and perhaps run the risk of puncturing."
"We sometimes hesitate to stop to change tyre pressures," relates Nani Roma. "Yet it can be absolutely necessary. It is difficult, impossible even, to drive a car when the tyre pressures aren't suited to the terrain. There is a great deal of tactics involved and you can't afford to get it wrong. You have to realise that stopping for a minute can actually pay back in terms of your stage time..."
"There's the psychological aspect, too" adds Luc Alphand. "No driver wants to stop during a stage. At times, we try to pass a series of dunes without getting out of the car, but you can end up digging yourself into the sand if you try to run with pressures that are too high. At others, we might be tempted to cover a high-speed portion with low pressures, but this can lead to tyre damage and a risk of puncturing. Sometimes it's a question of luck."
The necessity to run with correct tyre pressures and the knock-on effect not doing so can have underlines the importance of tyres in rally-raids. "We enjoy an increasingly strong relationship with our partner teams," says Dominique Bravy. "They pay increasing attention to this aspect and I am sure the 30th anniversary Dakar will once again highlight the key role BFGoodrich tyres play, both during the teams' preparations for the event, as well as once it starts, of course. We work closely with them to give advice and help in the way they take the tyre factor on board."
"The route of the 2008 Dakar promises to be very challenging indeed," warns Luc Alphand. "The menu of four stages in Morocco and seven in Mauritania won't be easy, but the combined experience of Mitsubishi and BFGoodrich should be a big help in our bid for victory."