Hot and rainy Malaysian race to put Pirelli's new tires to the test

The teams will also try out an experimental compound of hard tire. Two sets of this new version of the hard tire will be given to the teams for Friday’s two practice sessions only, in order to evaluate feedback in the demanding rainy and hot conditions of Malaysia. The remaining tire allocation for the weekend is unaffected.

The hard and the soft tire will be the prime and option choices for the Malaysia, as was the case in Australia, but with rain such a common feature of Malaysia, the intermediate and wet tires are likely to take center stage as well.

The intermediate tire, distinguished by light blue markings, has a tread that is characterized by light grooves across the whole surface of the tire.

The wet tire, with orange logos, has an asymmetric tread design. The pattern is denser on the outer edge of the tire, while a center channel and two smaller channels of the inside of the tire help to disperse water more effectively.

The amount of water displaced varies according to the depth of the grooves. The grooves on the intermediate tire are three millimeters deep, meaning that they can cope with standing water that is around two millimeters deep.

Any more water than that and the wet tire is required. The moment at which it becomes quicker to switch from the intermediate to the wet tire and vice versa – the “crossover point” – is of vital strategic importance, and will hold the key to the teams’ tactics in Malaysia.

The wet tire has a tread depth of five millimeters and is able to cope with a level of standing water of up to five millimeters before aquaplaning sets in. One of Pirelli’s wet tires will clear up to 60 liters of water per second at 186.411 mph, meaning that a Formula One car at full speed will clean up 240 liters of water per second.

The intermediate tires by contrast clear 20 liters of water per second, as opposed to a road car tire that can only clear 10 liters per second – but at much slower speeds.

Malaysia presents a stark contrast to the first Grand Prix of the year in Australia, with hot and humid weather matched to a much more aggressive surface. This should lead to three or four pit stops during the race.

The Sepang circuit is 3.44 miles long, with the total of 56 laps that comprise 192.878 miles. The track is well known for being tough on tires, and that is evident from the very first hard braking area into turn one.

The second turn is even tougher; the unevenness of the surface and the stiff suspension means that the inside wheel often lifts, putting all of the load on the outer front tire.

After the opening complex of corners there is a long right-hand bend taken at 155 mph. This turn tends to result in understeer, forcing the driver to make a correction. The front left tire, which does all the work here, is subjected to a vertical load of 1,829 pounds.

As well as the two main straights, unusually separated by a hairpin bend, there is a quick succession of fast corners that impose a lateral acceleration of more than 3G on the car and tires. The left-rear tire temperature gradually rises to a peak of 302 degrees F on the inner edge while accelerating out of the corner. The famous hairpin bend between the two straights is not only crucial, but a key area of stress for the tires, combining braking, turning and acceleration at the same time.

“Australia went very well for us but this will be another type of race entirely,” says Paul Hembery, Pirelli’s motorsports director.

“About the only thing you can rely on here is the fact that it will rain hard in the afternoon and because of this we expect our wet tires to play a key role here. When it’s dry, we expect the hard tire to be well-suited to the conditions, as ambient temperatures are going to be a lot hotter than they were in Australia,” he explains.

“Due to the aggressive surface that we have in Malaysia and the hot weather, we expect to see more pit stops; about three, which could increase to four if the teams have to change between wet tires, which is more than likely,” says Hembery.

“Before the race, the teams will have a chance to try out a new hard compound tire during Friday’s free practice session. This tire represents a new philosophy in the compounding and it will be interesting to hear the teams’ feedback. Generally speaking it’s a more durable tire but we need to be careful not to be too conservative: The emphasis is still firmly on entertainment and putting on a great show for the crowds.”

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