British Grand Prix in 90 seconds
By Mark Hughes
BBC F1 commentary box producer
Does Red Bull's stunning form at the British Grand Prix signal the start of a dominant second half of the season for the team - and therefore a very close championship battle with Brawn's Jenson Button, the runaway points leader? Or was it just a one-off, explained by a specific problem for Brawn?
The dominance of Red Bull's heavily revised RB5 at Silverstone was certainly impressive. Fuel weight-corrected, it had a margin of around 0.6 seconds on the rest of the field in qualifying and Sebastian Vettel and Mark Webber duly romped to a comfortable one-two in the race.
It was the first time the Brawn had been beaten in the dry, but there were similarities between what happened at Silverstone and in the wet Chinese Grand Prix, the other race this year where Red Bull scored a one-two.
On both occasions the Brawns were struggling to get their tyres into their working temperature range.
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Racing tyres are extremely sensitive to their temperature. They are designed to work between around 80-130C. This is the range at which the rubber bonds to the surface of the track at a molecular level and is referred to as 'chemical grip'.
The other mechanism by which a tyre generates grip is by the elasticity of the tyre reacting against the cornering force with an opposing force. This is termed 'mechanical grip'. The mechanical grip induces temperature in the tyre which then triggers the chemical grip.
If a tyre is running below its optimum temperature, the rubber is not elastic enough to generate good mechanical grip and the chemical grip is not triggered.
Different cars work the tyres in different ways according to their weight distribution, suspension geometries and aerodynamic loadings. The Brawn is easier on them than any other car.
This is an advantage at tracks where the challenge is to stop the tyres going beyond their working temperature range - when they get too hot the rubber becomes too soft to withstand the mechanical loadings - but obviously a disadvantage when the tendency is for the tyres to run cool.
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At Silverstone there is relatively little braking - which helps generate heat - and the track temperature itself was cool.
For this reason, Silverstone did not see the best of Brawn.
On the other hand, the Red Bull's revisions brought it a very significant improvement. How much of that 0.6secs margin was one, how much the other? It's impossible to accurately gauge but it is more than feasible that tyres out of their temperature zone could cost that much lap time.
If that was indeed what happened, will Brawn's superiority re-emerge at more conventional tracks with plenty of braking and higher temperatures? Not necessarily.
There's reason to believe the changes made to the Red Bull - essentially a complete repackaging of the car that allows the downforce-inducing 'double diffuser' a bigger inlet area - will allow it to retain the superb fast-corner performance it has always had but combine it with with slow-corner capability that might more nearly match the Brawn's.
The new diffuser should be able to retain more of its downforce at lower speeds, thereby attending to the RB5's previous weakness.
That offers the possibility of a Red Bull that might well now be every bit as fast as the Brawn on conventional tracks - and sure to remain faster on those with lots of high-speed corners or cold or wet track surfaces, such as the races still to come at Spa and Suzuka.
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If the Red Bull can do that, it is essential - given Button's big points advantage - that the team focus on one driver for their championship challenge.
Yet Sebastian Vettel and Mark Webber are still only a few points apart and it would surely cause some disharmony if the Australian was asked at this early stage to support a Vettel title campaign.
Vettel remains the logical choice, though. He is the guy that has won two races this year, after all. It promises a real challenge for the team's management.
Of course, that would all be immaterial if Brawn's development programme can match that of the Red Bull's and it reverts to being the fastest car.
Mark Hughes has been an F1 journalist for 10 years and is an award-winning author of several books