Searing heat and efficient stage starts: two further challenges faced by tires
In addition to searing heat, the day’s menu featured a daunting cocktail of sand, fast tracks, rough, stony dirt trails and more exacting navigation which put crews to another taxing test, especially as the fatigue accumulated since the event’s start is beginning to take its toll.
It was yet another challenge for the new BFGoodrich® KDR2+ which has so far taken the all the difficulties inherent in the world’s biggest cross-country rally in its stride, including the sand dunes, mud and high altitudes it had to contend with earlier in the rally. Today’s hot weather provided an added complexity. “As the tires heat up, their pressures increase, too,” explains Matt Hanlon, the engineer who oversaw the KDR2+’s development. “The crews of the two-wheel drive cars are authorised to adjust their tire pressures on the move from inside the cabin, but crews of four wheel-drive cars aren’t allowed to do this, so pressures can climb considerably.”
Stéphane Peterhansel (N°300 PEUGEOT 3008DKR Maxi) (2nd overall):
"Given how fast we’ve been going through the prickly scrub in our PEUGEOT 3008DKR Maxi, it’s amazing that we haven’t picked up any punctures!"
On top of that, today’s competitive action was divided into two parts, which meant tires had to start twice from standstill. As a car powers away from the start-line, the speed at which its wheels to rotate needs to be a function of the car’s own speed, otherwise you get wheel spin which, in turn, leads to a loss of traction. Today’s cars are equipped with electronic traction control, but a rate of wheelspin of 5 to 10 percent can result in a complete loss of grip. “The new tread pattern we designed for the BFGoodrich® KDR2+ delivers more efficient traction,” says Matt.
This is a significant change for the four-wheel drive runners, including the likes of Nasser Al-Attiyah, who tend to have the edge over their two-wheel drive rivals in this situation, as testified by the visible leap forward of the Toyotas and the dirt they throw up as they move off the line. The Peugeot and Mini 2WD drivers have to focus on pulling away more smoothly before pressing hard on the accelerator. Otherwise, they run the risk of remaining on the spot if they unleash too much power when the officials wave them off.
With two stages still to come before the 2018 Dakar ends, tires can still make a real difference.