What will Brazil F1 tire test reveal?

ERJ staff report (TP)

São Paulo, Brazil − Pirelli will test a prototype of their 2014 tire for the first time in Brazil this weekend – but how will the big technical changes in F1 next year change tire design and what will the test tell them? Reported Will Gray for Eurosport.

At Interlagos, each car will have two sets of next year’s tires to use in FP1 and FP2. These tires will have the provisional 2014 construction and profile and use the 2014 medium compound.

They have the same dimensions as the current tires but will be of a completely different design, constructed to cope with much greater forces that the 2014 cars will produce.

The combination of the new turbo engines and enhanced energy recovery systems is expected to deliver more power than the current V8 engines – with reports suggesting total output could be around 850bhp, some 70bhp more than this season.

The turbo engines will also produce torque in a completely different way, with the transmission almost constant throughout the rev range, while the electric motors of the ERS systems will deliver almost instantaneous torque when they are used.

Changes to aerodynamics, although less significant than originally planned, will also have an effect, with a drag reduction increasing straight-line speeds. Downforce has also been reduced, but reports suggest development in this area has enabled teams to recover much of the loss so cornering speeds could be similar to those currently seen.

All this puts extra stress on the tires, particularly the rears, with the very real potential for drivers to wheelspin even in high gears.

If that went unchecked, it would lead to overheating, high wear rates and extreme degradation, so much that Pirelli has reportedly claimed the 2014 cars would shred the current tires in a handful of laps.

Fundamentally, therefore, the tires will require more grip – some reports suggest as much as 10 percent more – to cope with this.

But so far Pirelli has been almost developing in the dark.

There are simulation tools available but with such dramatic changes, and such intelligent engineers locked away in F1 design offices around the world, it is hard for the tire manufacturer to predict exactly what performance levels next year’s cars will be at.

The top-secret nature of development means any clues are hard to come by, and earlier this month Pirelli boss Paul Hembery admitted that the development process has been made significantly harder because teams are unwilling to share their performance predictions.

To design a tire, Pirelli needs to know top speeds, lateral loads, vertical loads and aerodynamic loads, all of which determine exactly what loading is being put through the tires at any time.

With limited data, they have had to take the worst-case scenarios of what they do have, and that means their tire designs will be more on the conservative side.

Such is Pirelli’s concern, they even asked for a dimension change as they feared the size of the existing tires would not give them enough structural strength to play with.

This was a late call. They were pushing for a change in July, well after these crucial dimensions had been set and teams had used them to design their cars around. Unsurprisingly, the teams vetoed any change, so Pirelli have had to design around it.

That will almost certainly mean they will create stiffer tires with more robust compounds, and that will mean they will have less of an influence on performance than they have had over the last few years.

The other consideration to be made is that Pirelli may need to evolve their tires over the season.

Whenever a new design phase is begun, the pace of development at its early stage is much faster because there are far more areas to explore. Teams have spent almost two years working on the new regulations, but there is still likely to be many different avenues in the deeper detail that have not yet been explored – and that could see cars getting dramatically faster throughout the season.

So this weekend is just a start. The relative lap times on Friday (22 November) may give some sort of indication of how conservative Pirelli has been, but it will do little more than that.

And for Pirelli, having the performance information feed once the season kicks off, and having the opportunity to make changes if they need to, is far more relevant than what they will learn in Brazil...

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Full story from Eurosport