Fault lines begin to appear inside the McLaren garage

By Mark HughesBBC F1 commentary box producer

McLaren's sudden lack of competitiveness at the European Grand Prix seemed to release into the open some of the underlying tensions in the team.

The reality of their dip in form at the Spanish track was really nothing more than the specific combination of tyre behaviour, a very high track temperature and the car's characteristics.

There was absolutely nothing to suggest that the car that was fastest on race day in the previous three events was suddenly intrinsically way off the pace rather than merely out of its set-up window.

The McLaren car's form in Valencia does not mean that it will be 40 seconds behind the best Ferrari again at the end of the Silverstone race, despite Lewis Hamilton's initial downbeat assessment of his chances at Silverstone.

But both Hamilton and, to a lesser extent, Jenson Button were critical of the team post-race.

Button suggested that they "need to start taking more risks" in the car's development. Hamilton complained that recent developments - such as the new front wing introduced at Valencia - concentrated on front downforce but that it is the rear of the car that most badly needs a downforce boost.

Certainly, had the car enjoyed more rear downforce at Valencia it would probably not have overheated its rear rubber so much.

It was this that was largely responsible for a race pace that averaged around 0.8 seconds a lap slower than Red Bull's and Fernando Alonso's Ferrari, and which led to Hamilton quickly destroying the tyres in his first two stints.

The way a car's downforce interacts with its tyre grip is not straightforward and can often give what to the layman appear anomalous outcomes.

With this generation of Pirellis, it is inevitably the rear tyres that are the issue and there are basically two different ways they can overheat.

If there is too much downforce working upon the tyres, it can give them heat degradation, where the entire structure of the tyre becomes overworked.

In this case, the downforce is essentially over-stressing the tyre and the rubber's various chemical bonds begin to break down, leading to a reduction in grip. Were there still a tyre war, the tyre company would simply make a stronger construction for the cars with greater downforce.

Confusingly, a lack of downforce can also overheat the rubber - by allowing too much wheelspin and not pressing the tyre down hard enough through the corners.

This will overheat the surface of the rubber more than the inner structure, which remains cool through not being loaded up enough.

This makes things even worse, as the structure of the tyre is not bending enough to allow it to grab the track surface, meaning the tyre's contact patch gets 'wheel-spun' - dragged across the road - thereby overheating it even more, giving it even less grip, allowing the core of the tyre to cool even more in a vicious circle.

This is what was happening with the McLaren at Valencia.

The circuit's many low-gear acceleration zones combined with a track temperature of 46C - by far the hottest track surface the Pirellis have ever been subject to - to make the McLaren's rear downforce level horribly inappropriate.

But that same rear downforce deficit has almost certainly played its part in McLaren being faster than Red Bull on race day at Barcelona, Monaco and Montreal.

The Red Bull's big downforce that tends to overwork its rubber helps in qualifying by getting the tyres quickly up to temperature, but gives the tyres more heat degradation over a race stint.

There are other factors too - the difference in emphasis between the performance of the cars' rear wings with the DRS overtaking aid deployed or not, or McLaren's more reliable Kers power-boost system, for example - but the differing tyre usage borne of the differing downforce created by the two designs is probably key.

Valencia simply created the set of circumstances that exposed a weakness in the McLaren that can usually be overcome.

It had a very narrow set-up window in those circumstances, and the Red Bull and Ferrari did not.

McLaren and Hamilton found that window in qualifying but the hotter conditions of Sunday dropped them back out of it.

Lewis Hamilton
Hamilton has been on the podium three times this season

What is probably more significant than the fact of the car's struggle around the Spanish track is the frustration it unleashed in the drivers.

Someone who should know said in Montreal that Hamilton was "one unhappy bunny at McLaren and would leave tomorrow if he could".

But Hamilton has publicly stated his desire to stay with the team despite his recent form.

Button arrived in Valencia on the back of his stunning Canada win, talking openly of fighting for the championship, encouraged by the McLaren car's recent run of race day speed.

Just as he seemed ready to step up to that challenge, he found himself in a car that was nowhere near the pace.

Team principal Martin Whitmarsh put a brave face on it post-race, saying: "You want your drivers to be asking for more downforce and more power. What sort of racing drivers would they be if they weren't always asking for that?"

But the visibly irritated manner of the normally urbane and smooth team boss suggested something more was troubling him than just the occasional off-the-pace weekend that is a normal part of even a front-running team's season.

It would be highly surprising if the McLaren was not at least back on level terms with the Ferrari at Silverstone, and possibly back to threatening the Red Bull again.

Certainly it will have a new, more aggressive, rear wing in line with the Red Bull's in how it balances the DRS/non-DRS performance.

But the bigger question is: will that be enough to bring some serenity back to this team?