Diffuser boosts Hamilton but Button shines

Bodywork change speeds up world champion as Brawn rivals play catch-up

McLaren yesterday became the first team to take tentative steps towards parity with Brawn, Toyota and Williams in the wake of the FIA court of appeal ruling on aerodynamic diffusers, when Lewis Hamilton tried revised interim bodywork on his MP4-24 to set the fastest time in the first practice session. But by the end of the day it was Brawn's Jenson Button who continued to set the pace as usual.

"The car instantly felt a bit better," Hamilton reported. "I can definitely feel more stability and downforce from the front. We've definitely made a step forward for this race. The car feels much stronger through the corners and I think we've got a very positive baseline for the rest of the weekend."

As all of the "non-diffuser" teams have now been obliged to invest in the technology exploited already by Brawn, Toyota and Williams, the appeal judges' ruling in the latters' favour has not been universally popular. Renault plan to have a revised diffuser on Fernando Alonso's car today. McLaren will have further revisions for the start of the European season in Barcelona next month. But Ferrari will have to wait until Turkey and Red Bull, whose car needs a significant redesign, may have to wait longer still.

"For us it has a significant impact because obviously we designed the car around how we believed the regulations should be interpreted and obviously came up with a very good car," said Red Bull team principal Christian Horner. "The benefit that diffuser offers is significant and obviously, if you haven't incorporated it into the car design from inception it is something that is difficult just to bolt on."

"It is definitely not sufficient and not possible to just exchange the diffuser and come with a new solution at the rear underbody," said BMW Sauber's Mario Theissen. "We have to redesign at least the aero package. I wouldn't go as far as Christian [Horner] and say it is a completely new rear end with our car, but the aero package will be totally different.

"We will have an aero update for Barcelona. But I cannot tell you today if the diffuser will be included or not. It is part of a lot of ideas and a lot of developments we are following and the final package is not decided on yet."

It remains to be seen whether the controversy which has divided the teams will impact on their unity in political matters. "I really hope not," said team owner Ross Brawn, whose cars have been so successful partly because of their designers' clever interpretation of the rules. "We have to learn that on one side of the business we must all work together for the future, while on the other we can fight cat and dog on the track. If we can learn that, then FOTA [Formula One Teams Association] will have a future.

"I can learn that principle and I think Stefano Domenicali at Ferrari agrees, but let's just say that certain elements elsewhere do not want that to happen. Certain people are trying to pour oil on troubled waters while others are pouring on fuel, and I'm not talking about the FIA here."

Oblivious to all this, Button said: "The balance of the car really improved over the last couple of runs today after we had struggled to find the right set-up early on. We completed a great deal of work with the two very different tyre compounds to establish what condition they would be in after longer runs. It was a useful first day of running but we still have some work to do."

Chinese Grand Prix: Practice times

First Practice Session

1 L Hamilton (Eng) McLaren, 1 min 37.334sec;

2 J Button (Eng) Brawn, 1:37.450;

3 R Barrichello (Br) Brawn, 1:37.566;

4 H Kovalainen (Fin) McLaren, 1:37.672;

5 M Webber (Aus) Red Bull, 1:37.752;

6 J Trulli (It) Toyota, 1:37.764;

7 N Rosberg (Ger) Williams, 1:37.860;

8 T Glock (Ger) Toyota, 1:37.894;

9 F Alonso (Sp) Renault, 1:38.089;

10 S Bourdais (Fr) Toro Rosso, 1:38.195;

11 K Raikkonen (Fin) Ferrari, 1:38.223;

12 S Vettel (Ger) Red Bull, 1:38.274;

13 S Buemi (Swi) Toro Rosso, 1:38.307;

14 A Sutil (Ger) Force India, 1:38.319;

15 F Massa (Br) Ferrari, 1:38.418;

16 N Heidfeld (Ger) BMW, 1:38.456;

17 G Fisichella (It) Force India, 1:38.460;

18 R Kubica (Pol) BMW, 1:38.463;

19 K Nakajima (Japan) Williams, 1:38.730;

20 N Piquet Jnr (Br) Renault, 1:38.825.

Second Practice Session

1 Button 1:35.679sec; 2 Rosberg 1:35.704;

3 Barrichello 1:35.881; 4 Webber 1:36.105;

5 Vettel 1:36.167, 22; 6 Trulli 1:36.217;

7 Nakajima 1:46.377; 8 Glock 1:36.548, 40;

9 Kovalainen 1:36.674; 10 Bourdais 1:36.800;

11 Sutil 1:36.829; 12 Massa 1:36.847;

13 Hamilton 1:36.941; 14 Raikkonen 1:37.054;

15 Buemi 1:37.219; 16 Piquet 1:37.273;

17 Kubica 1:37.491; 18 Heidfeld 1:37.544;

19 Alonso 1:37.638;

20 Fisichella 1.37.750.