The 2007 Rally Ireland marked the end of the reign in the World Rally Championship of the g-Force Profiler, an ultra-high performance dry weather asphalt tyre that owes its origins to the FP generation ('Fort Potentiel', or 'Strong Potential') tyre first seen on the 1998 Sanremo Rally. In the space of ten years, the FP has won 39 of the 40 asphalt WRC rounds contested and the g-Force Profiler went unbeaten in 2006 and 2007.
BFGoodrich's exit from the championship at the end of the current season and the new regulations that are due to come into effect in 2008 mean that WRC drivers will no longer be able to benefit from the outstanding grip provided by the g-Force Profiler dry weather asphalt tyre.
"I took all my wins on asphalt with this type of tyre," says Sébastien Loeb who has dominated seal surface events in the past three years. "The g-Force Profiler is essentially a racing tyre; that is to say it is rigid and responsive. It is also very progressive when the amount of grip or type of surface changes, for example. Another of its advantages is that certain compounds like the '0+'' (soft-medium) and the '2' (medium) compounds cover a broad spectrum of conditions which means they are competitive in changeable conditions. Indeed, the medium compound gave me incredible grip even in rain in Spain this year."
Prior to the 2007 Monte Carlo Rally which he contested with BFGoodrich, Petter Solberg had only driven once on FP generation tyres (1999 Sanremo Rally, Ford Focus): "I was surprised by how consistent the g-Force Profiler was, as well as by its ability to stay competitive over the full length of a stage, even in changing surface conditions."
His team-mate Chris Atkinson first ran with this product this season: "Second time over the 46km 'Saint Pierreville-Antraigues' stage, the performance of the medium compound ('2') g-Force Profiler didn't drop off at all."
The following day saw the Subaru Impreza WRC2006, on BFGoodrich tyres, take its first dry asphalt stage win since the car's launch the previous year.
The g-Force Profiler, which began its career with a win on the 2006 Monte Carlo Rally, is a direct descendant of the 'FP' generation which the Michelin Group launched in 1998 and which marked a leap forward in terms of performance on sealed surfaces thanks essentially to its new, more rigid construction.
In the space of ten years, the construction of the WRC asphalt tyre has hardly evolved which, given the competition it has faced, underpins its efficiency.
The construction of a tyre is just one of the performance parameters, however. The chemists, engineers and development staff have put in a great deal of work on compounds, too, with a double objective: adapt them to the new construction and also broaden the spectrum across which each compound can function to anticipate future changes to the regulations.
Indeed, given today's restrictions concerning the numbers of tyres authorised for each rally, compounds must now function across a temperature range of 15°C and no longer just 5°C. For example, a medium-soft compound ('0+') is designed to deliver optimal performance from 0 to 15°C and no longer just from 0 to 5°C as was the case, say, fifteen years ago when drivers had perhaps a hundred or so tyres available for every rally.
Finally, to match the compound to the conditions of the moment, drivers use a technique known as 're-cutting' which involves hand-carving extra groves into the tyre's tread, or widening existing grooves, to help the compound reach its working temperature more quickly or to clear water and/or mud if necessary. This job is carried out by BFGoodrich staff in the service park.
