Will Gray

Technical Talk: Picking the right tyre

Will Gray

View photo

.

Predicting the weather is a massive gamble and last weekend the Sepang roulette wheel failed to come up red after Ferrari took a punt on the black rain clouds bursting open for them on lap 18 when, with the track bone dry, Kimi Raikkonen came in for a set of wet tyres.

It looked a big gamble at the time — but sometimes, Ferrari thought, fortune favours the brave. Not this time. Not by a long shot. Their former super-strategist Ross Brawn must have been smiling after this one — but at Ferrari it is no laughing matter, and heads could roll.

So just how bad (or unfortunate) was Ferrari's decision?

Heavy rain was expected for the race and Bridgestone predicted that when the track started to become wet, the cars on dry tyres should continue on dry tyres until they were setting lap times around 15 seconds slower than they had been lapping on a dry track, after which they should change to wet tyres.

Likewise, they said, intermediates would be worth swapping to if the lap times they were running on dry tyres were around 10 seconds slower than they had been on a dry track — but teams were not expecting to use the intermediates because the tropical downpours seen in Malaysia would soak the track so quickly the intermediates would quickly be useless.

With no rain on the track at the point Raikkonen pitted, the cars on dry tyres were still running at relatively normal pace — but that was the gamble. If the heavens opened on that lap or the next, Raikkonen could fast-track all the way to the front on a settled pair of wets while the rest of the cars tip-toed around in undriveable cars, trying to avoid sliding off the track on their way to the pits.

Raikkonen was running fifth, 27 seconds behind leader Jenson Button's Brawn, when he stopped on lap 18.

On lap 19 Raikkonen did a 2:20 lap, including pit stop, while Button set a time of 1:39 - gaining 41 seconds on Raikkonen on one lap. The Brawn driver came in for fuel on that lap and, resisting the gamble to go for wets, stuck to dry tyres.

On lap 20 Raikkonen and Button's times were matched, at around 2:00 including the time Button spent stationary in the pits. But while the Ferrari driver continued at that pace, with the track still bone dry Button set times of 1:38 and 1:47 on laps 21 and 22 - gaining a further 35 seconds in two laps.

On lap 23, Button decided to pit for wet tyres when the rain came down and Raikkonen had the advantage, setting a time just under two minutes while Button ran just under 2:19, including his stop - losing 19 seconds to Raikkonen.

By the time things settled down on lap 24, with both Raikkonen and Button on the same tyres, Raikkonen was one minute and 27 seconds off the lead. And so, a gamble that could have put Raikkonen ahead if conditions had played into Ferrari's hands had actually cost him a full minute in just six laps.

In contrast, Toyota's gamble at putting Timo Glock on intermediates was an inspired move.

Glock was in 11th place, exactly one minute behind Button, when he and everyone ahead of him stopped to change tyres on lap 22. All the other teams chose the wet tyres, expecting the rain to pour down in buckets, but it did not and Glock's intermediates were the right tyre to be on.

Glock's lap was between three and five seconds faster than the other drivers who had stopped and his first clear lap was five seconds faster than the whole field. He set the fastest time on laps 24, 25 and 26, and by lap 28 he was in second place having taken 35 seconds out of Button's lead in just six laps.

But at the end of the day, while teams up and down the pit lane tried to play the weather to get ahead, Button and Brawn were sitting pretty.

Sure, they put wet tyres on when intermediates would have been better — but with a car and strategy that had put them in front in the dry, they were able to calmly calculate their way to victory. There was no need to gamble. All they needed to do was match their closest rivals.

 

DATE PUBLISHED ON: 7 APRIL 2009

View comments (0)