Paul Hembery at the 2012 German Grand Prix (© Foto Ercole Colombo)

There have been two changes for the 2012 Formula 1 season which have made it one of the best in many years. Arguably, the most important feature which has given F1 eight different winners and many thrilling races so far this season is the change in tire performance.

Today we sat down with Pirelli Motorsport Director Paul Hembery to learn more about how tires would play a part in the outcome of this weekend’s race.

Earlier this year, molds of Circuit of The Americas were taken and laser scanned by Pirelli engineers.  Once translated into a 3D model, engineers combined energy simulations supplied by teams to produce a performance model to allow testing of tire compounds. Using this data, Pirelli chose the P Zero Silver hard and P Zero White medium compound tires for the USGP; this combination is the same as what was used at Monza and Spa this year.

However nothing beats real world experience, and with feedback from practice and qualifying sessions now in the hands of Pirelli, there have been unexpected obstacles to overcome. The surface of COTA, explained Hembery, is smoother than simulations showed. When compared to circuits like Monza and Spa, both fast and harsh on tires, COTA is less abrasive, making harder tires more difficult to wear-in and reach the target performance zone.

In addition to the texture of the track, the cool fall temperature is also affecting performance, making it more difficult to get heat into the hard and medium compound tires and give them more grip. Each of these factors, Hembery explained, means that Pirelli could have opted for softer tires, making their choice a bit “conservative” for the USGP.

To some extent, this means the hard and medium tires could last the entire race themselves even though both must be used for at least one lap. The grip fall-off, which has played a critical role in effecting the strategy and delivered many exciting races this year, will not be a factor tomorrow and should be very predictable now that both compounds have been tested on track.

The fan favorite feature of COTA, Turn 1, might put significant vertical load on the tires, but Hembery assured that the tire structure is significantly over-engineered, and there is no risk of failures from the high loads going up into Turn 1.

The 2012 season has been incredibly exciting and Pirelli has played a key part in delivering the on-track race action. Now that the season is winding down, the development of the 2013 tire is underway. Pirelli's approach to the significant challenge of delivering a tire that improves race action has proven to be wildly successful. For 2013, Hembery explained, expect more.  The tires will be more aggressive and the variations between compounds will ensure race action is even more dynamic.