Pirelli rear F1 tyre design reacts to new aerodynamic regulations

Pirelli will enter its second season of Formula One as exclusive tyre supplier this weekend at the Australian Grand Prix; previewing the race, the tyre manufacturer has outlined another of the ways its tyres have changed since last season, responding to new aerodynamic and technical regulations, which have had a profound impact on car design. The banishment of blown diffusers – with the exhaust outlets now having to exit the car higher, pushing the centre of pressure forwards – have resulted in reduced grip at the rear, meaning that Pirelli has had to rise to the challenge of increasing the grip given by its rear tyres.

Pirelli has reacted to the new regulation, which pushes downward force to the front axle, by giving the rear tyres more grip and adopting squarer profiles to increase the contact patch. The new profiles are designed to distribute stresses more evenly across the entire tyre footprint, compensating for the greater stress they will be under, as driving styles become increasingly complex and aggressive to deal with the reduced grip at the rear.

Pirelli explains further that a greater proportion of force on the front axle means that there is better turn-in and superior driving precision in corners, as well as improved medium-speed to high-speed direction changes. But with the forces moving more towards the front of the car, a weaker rear end means that the rear tyres have to work even harder to avoid sliding through corners, as well as combating wheelspin under acceleration.
 
The driving style needed to control the rear during these periods of oversteer and wheelspin puts plenty of stress onto all the tyres, which translate into higher working temperatures on both the front and the rear. As a result there is more rear degradation and a balance that moves towards oversteer during a race stint.

Another important new tyre regulation for 2012 is the fact that drivers can have all 11 sets of their weekend’s allocation available from Friday. This is designed to avoid drivers limiting their running in order to save tyres for later, and it should give spectators the chance to see more action.
 
Pirelli has also worked to improve spectators’ understanding of team tactics with more prominent colour markings, and a new name for the wet-weather tyres: Cinturato.

Melbourne’s oversteer challenge

Pirelli says that the life of a tyre at Albert Park evolves over the course of the weekend as the circuit rubbers in and gets progressively faster. The manufacturer identifies a comparatively high level of downforce, used by teams to tackle the quick succession of corners, and oversteer on the exit of corners contributing to higher stress on all four tyres.
 
A place where the tyres and cars are worked especially hard is turn two. The drivers scrub off 200 kilometres per hour in just 2.5secs and 108m under braking, subjecting themselves to a 5G deceleration while the front tyres are pushed into the ground by 1150 kilograms of downforce.
 
Turns 11 and 12 are two of the key points of Albert Park. The exit speed from the corner is in the region of 210 kilometres per hour. The stressed front tyre (on the outside of the curve) is operating at around 105°C, whereas the inside tyre on the right has slightly less work to do and runs five degrees cooler at around 100°C. The rear tyres operate at temperatures in excess of 100°C.
 
Another important area is the braking zone between turns 14 and 16, which loads the front of the car heavily leading into a chicane with tight right-angle corners before the main straight. This is the only place on the track where the cars top 300 kilometres per hour in seventh gear, and it is where the left-rear tyre has its temperature peak.