Big changes in the set-up!
The first two rounds of this year's Intercontinental Rally Challenge could not provide a greater contrast to each other: from the snow and ice-covererd asphalt of Monaco and the Col de Turini, the IRC competitors will now move to gravel on the
other side of the Atlantic in Brazil, where temperatures are set to be dry and warm.
In order to make the transition between surfaces presenting such different characteristics, a number of modifications need to be made to the cars.
The biggest change between a gravel and asphalt set-up is that the cars ride much higher on gravel. This is because the roads are rougher, so the cars need to be tall enough to pass over most surface obstacles and provide enough suspension travel to absorb jumps and bumps.
As a result the suspension set-up on each car for gravel tends to be a lot softer than it is for asphalt, enabling the cars to flow better over the rough roads.
The tyres are also very different. Gravel tyres are tougher, in order to resist punctures, and they also feature a distinctive deeply-grooved pattern to expel dirt, dust and debris.
The wheels and brakes on gravel tend to be smaller than those seen on asphalt rallies, as the braking forces are less because the cars slide more (due to the loose surfaces involved offering less traction and grip).
As a result, the physical forces exerted upon the drivers tend to be smaller, thanks to the lower G-forces that are generated.
However, one extra problem that the cars will have to face in Brazil is cooling. The low ambient temperatures in Monte Carlo meant that it was comparatively easy for engines and brakes to stay cool, but this will not be the case in the higher temperatures of Brazil – where it could be easy for overheating problems to appear.
Although there are many subtle differences between an asphalt and a gravel set-up, a skilled group of mechanics can swap a car from one configuration to another in just a couple of hours. This will have taken place back at base, before the cars were all shipped off to South America over a week ago.
The IRC's second round of the 2009 season begins in a few days with the Rally Internacional de Curitiba, from 5th to 7th March.