MPH: Mark Hughes on...

At Interlagos there seemed to be a thousand-and-one things going on beneath the radar while the front-of-F1 shop presented a thrilling title showdown.

The teams were trying to agree among themselves what they might present to the FIA as their vision of the future, trying to ease the tension between their determination to remain united, their differing interests and their uncertainty about the FIA's agenda and strategy.

Then there was another little matter that may be less crucial to the future of the sport but could be absolutely critical to the future of certain drivers within it: how kinetic energy recovery systems (KERS) might be about to impact on their market value.

Sound incongruous? Whatever could KERS have to do with the prospects of individual drivers? Quite a lot if you happen to be at the taller or heavier end of the F1 driver scale.

The weight span between the various teams' KERS packages next year ranges from 25kg to 60kg. This is weight that would otherwise be allocated to ballast for the purposes of varying the weight distribution. Pre-ballast, the lightest cars currently weigh around 465kg, the heaviest around 485kg.

The regulations require them to weigh a minimum of 600kg - including the weight of the driver. What's left over between those two figures is used as ballast. The lighter the car and driver combined, the greater the choice of weight distribution, which can be an extremely important lap-time differentiator.

The weight of expectation

But for next year it's feasible that we could see cars potentially exceeding the minimum weight limit with their KERS fitted, in which case there would be no ballast with which to vary the weight distribution from track to track. At the very least, there will be considerably less ballast with which to play.

Suddenly the weight and size of the driver becomes absolutely crucial. Running above the weight limit is out of the question. On the average track each 10kg costs around 0.3sec of lap time. But even if you can make the weight limit, the heavier driver will still be significantly disadvantaged.

Already teams endeavour to get their baseline weight distributions as far forward as possible. It allocates the loads between the front and rear tyres better, given that the rears are deliberately under-specced for their workload by the regulations. The more load you can get off the over-worked rears and onto the under-worked fronts the faster, in theory, you'll go.

The advantages snowball too because the further forward you can get your weight distribution the further forward you can bring your centre of aero pressure - meaning more front/less rear aero, which is perfect because extra front downforce comes at negligible cost in drag but extra rear downforce invariably means extra drag.

Next year, it will be necessary to move the weight even further forward, as Patrick Head explains: "The likely consequence of our moving to slick tyres next year is that we will need a more forward weight distribution. When you take those grooves out it increases the contact patch area more at the front in relative terms than it does at the back.

"I'm not sure what it's like for others but for us it's very difficult to achieve the weight distribution we will need for a successful car next year because not only is pretty much all of our ballast taken up with a KERS system, we can't really run it any further forward than the area for the side-impact test.

"The difference KERS could make to a lap time will be between 0.1sec and 0.3sec, perhaps at the maximum 0.35sec. Having your weight distribution inappropriate for the tyres by more than one or two per cent will probably make more difference than that."

Ballast, in other words, is at even more of a premium - at just the time that KERS has taken much of it away. If we look at Red Bull as an example of how this impacts, there's no way it will be able to run as forward a weight distribution on Mark Webber's car as it will on Sebastian Vettel's, simply because of the weight and size difference of the pair.

On aero-crucial circuits Webber will be consigned to a less than optimum weight and aero distribution, won't get as good a response from the front tyres, will wear his rears more and will carry more drag. It will be a similar story at BMW where the diminutive Nick Heidfeld will be able to run a better set-up than the tall Robert Kubica.

When size does matter

It was suggested to Rubens Barrichello - at 71kg the heaviest driver at the beginning of this season - that it would be helpful if he shed a couple of kilos during the summer break and it didn't go down at all well when he returned 1kg heavier. KERS has got teams thinking ever more intently about their drivers' dimensions and weights. Honda's test driver Alex Wurz (187cm /79kg) may not get much testing of the KERS-equipped car next year. Anthony Davidson (165cm/56kg) is far better placed.

The bigger drivers are vexed by all this, only adding to the general disruption the KERS programme is causing.