Loeb On Top With Pirelli In Bulgaria

Borovets in Bulgaria was home to the tough 220.03 mile course of Rally Bulgaria, round seven of the 2010 World Rally Championship, of which Pirelli is the exclusive tyre supplier under a three-year agreement with the FIA, motorsport's world governing body.

It was the threat of unpredictable weather that made the availability of the soft compound Pirelli P Zero tyre essential for the competing crews. On gravel events, WRC regulations restrict drivers to a pre-determined compound of Pirelli's Scorpion tyre. On asphalt events, they can choose between the hard (for dry conditions) or soft (for wet conditions) compound P Zero, albeit with a restriction of 40 covers in total. In Bulgaria, they had an allocation of 34 hard compound tyres and 24 soft compound tyres, eight more than usual, following reports of possible thunderstorms.

Although the event was held in largely dry conditions, competitors were forced to choose between the hard and soft compound tyre due to overnight showers. Both types of compound use an identical tread pattern that aims to provide maximum contact with the road, however, the soft version is designed to provide more grip and stability in cold and damp weather conditions. Whilst, the hard version provides the optimum performance when the weather is warm and the road surface dry.
 
Sebastien Loeb, who won the rally, opted for the soft compound P Zero tyre for all of Saturday’s six stages to counter the potential threat of showers. While it proved a wise move by the factory Citroen C4 driver on Saturday morning, it was less inspired in the afternoon when it remained dry.

“We expected some rain so it was a safety decision because when you have water on the road the soft compound tyre is much better,” said Loeb. “If it’s dry we knew it would not be the best choice but we did not lose too much time because the grip under braking was still good when we used the soft compound tyre on a dry surface, although we could not be so quick through the corners because we have less lateral grip and you have to find a different rhythm for that.”
 
In the past, Pirelli engineers would have developed a tyre specifically for competition and for different levels of rainfall. However, because the FIA specified that the asphalt tyres had to conform to everyday road use regulations, the P Zero WRC cover is virtually identical to the tyres available for members of the public, albeit with even stronger sidewalls to combat the threat of punctures. Nevertheless, Loeb was quick to praise the performance of his Pirelli P Zero tyres.

“It’s been the perfect rally for me and very good for the championship,” said Loeb. “I am happy with the performance of the tyres and I was surprised that the soft was as good as it was in dry conditions when, for sure, it was not the best choice.”

Rally Bulgaria also marked the debut of Pirelli’s new RX tyre for use by Junior World Rally Championship competitors in place of the old RS design. Using the same technology incorporated into the 18-inch RX tyre, Pirelli has produced 17- and 16-inch versions to give the competitors in the young-driver class more precision, reaction, durability and consistency, particularly on some of the longer stages (the Batak Lake stage run twice on day one measured 19.74 miles in length) on the rally route.

Thierry Neuville, who claimed his maiden win in the JWRC class in a Citroen C2 S1600, said: “The tyre was working very well. (We) had a very good feeling and there is not much difference between how the tyre looked at the start and finish of the long stages. It’s very good work by Pirelli.”
 
“We are very satisfied with how this rally has gone for us,” Matteo Braga, Pirelli’s senior WRC tyre engineer, concluded.  “It is a new rally and the first round of the WRC on Tarmac this season so there was increased expectation. The teams are now clear about how the soft and hard tyres perform in different conditions and this is very important. Also, Petter Solberg used the same set of tyres on Friday’s stages, which covered (74.56 miles), and this shows the durability of the tyre is very good. We’ve seen no tyre damage or punctures although there were some junior drivers who had problems by cutting corners and hitting rocks, which broke rims rather than the tyre.”