Chinese Grand Prix: Friday practice sessions

April 18, 2014

Weather will have a big effect on tire behavior throughout the Chinese Grand Prix weekend, with free practice today characterized by cool weather and a possibility of rain for qualifying tomorrow. Ambient and track temperatures dipped to 55 degrees F respectively during FP1 this morning, before becoming slightly warmer in the afternoon.

As a result, the drivers had to be sure of warming their tires up properly, in order to extract the best possible performance and guard against graining. In order to warm up the compound, the driver has to gradually put more heat and energy into the tire during the out lap, so that the compound reacts with the surface to generate grip. Graining happens when the tire simply skates across the asphalt rather than bonding with it, causing wave-like patterns of wear across the surface of the tread. Graining was seen for some drivers during free practice, but it remained within anticipated levels.

Paul Hembery: “We’ve seen quite a big gap in terms of lap time between the two compounds today: between 1.4 seconds and 1.8 seconds depending on the team. These are exceptional circumstances because temperatures are a lot cooler than we would expect to see over the rest of the season, and with rain expected tomorrow, weather will obviously remain a big factor over the course of this weekend.

There’s been some graining, but no more than we would expect under these circumstances. We’ll analyze all the data tonight but so far we would expect the teams to get about 20 laps out of a set of soft tires and approximately 25 laps out of a set of mediums. Degradation on the medium tires is about half of what we are seeing on the soft tires: in terms of performance the medium tire loses about 0.15 seconds per lap in race trim, whereas the soft tire loses about 0.3 seconds per lap. We’re looking at between two and three pit stops on Sunday from what we can see so far.”

Free Practice 2:
 
Hamilton
1m38.315s – Soft New

Alonso
1m38.456s – Soft New

Rosberg
1m38.726s – Soft New

In the P Zero Magazine:
The brand new P Zero magazine, an innovation from Pirelli for this season, contains facts about the Chinese Grand Prix and everything else that is happening in the world of Pirelli from the past, present and future. This dynamic new e-magazine, which contains video and other interactive content updated over the weekend, can be accessed via Pirelli’s website or on the following link: http://magazine.pzero.com

Pirelli fact of the day:
The Pirelli factory in Yanzhou, China (one of two in the country) is the largest of the 22 factories in the entire group. Maximum capacity for car tires in the plant is up to 10 million units per year.