The Right Attire for Tyres
It’s all about the tyres again.
One thing this week in Barcelona’s confirmed is that, although the new Pirellis do indeed have a slightly larger operating temperature window than last year, we still saw most people struggling like mad to ‘switch them on’. Of course the first two days were simply too cold, I didn’t see the average temperature for that period, but I can tell you I needed a jumper, jacket and scarf in the pitlane and I haven’t been to many F1 races over the years where more than perhaps a gillet was required at worst.
I’m not sure Pirelli normally use a clothing based method to define the ideal ambient and track temperatures for their tyres to work in, but I would suggest that in Melbourne we need to be looking for short trousers if possible, but at the very least t-shirt conditions to get the best from the supersoft and medium compounds. If we’re not seeing predominant use of sunglasses and lotion around the paddock, we may find everyone wanting for more grip and going through tyres far quicker than intended.
To get back on track so to speak, we were seeing tyres on average, running in the second half of this test at temperatures around the 60-70 degree mark, still some way short of their intended or ideal working range of 75-100 degrees. The tyres, which incidentally aren’t rubber as they’re often referred to as, but are made up of a specific chemical, man made compound and engineered to ‘switch on’ or activate at a certain core temperature. By activate, I mean changing state slightly, becoming ‘sticky’ and reacting with the track surface to give the extra grip the drivers are looking for.
The temperature needs to be achieved in the right way, by heating the core of the tyre as well as the surface and working both areas simultaneously without pushing them too hard before the ‘critical’ level’s been achieved. The driver has various tools available to him to help with this, but needs a good understanding of how the process works in order to do it properly.
During an out lap in qualifying, or on the way to the grid, we’ve all seen cars weaving left to right and spinning up the rear wheels to increase tyre temp ready for the crucial lap, engineers are generally on the radio at this point informing the driver if he needs to work one end of the car more than the other as they monitor the numbers back in the garage (except in Kimi’s case of course, where he “knows what he’s doing”). The team can also ask the driver to adjust his brake balance, meaning the split in the amount of braking force applied to each end of the car when the brake pedal’s operated. The brakes generate an incredible amount of heat inside each wheel and that heat radiates through the wheel rim and into the tyre, helping to increase the tyre’s core temperature. By playing with brake balance on an out lap, the driver can create more heat at the front or rear, depending on where it’s needed.
McLaren developed a system on their car last season which utilised a pitstop adjustable opening in the brake ducts to allow more or less of the hot air from the brakes to be directed into the wheel and help during a race if the team was struggling to maintain the necessary temperatures. There’s talk of more teams working on similar systems on this year’s cars at the moment as tyres are proving equally important to get right.
Without the correct chemical reaction of the compound, the tyre simply doesn’t stick to the road, the car slides around, not only making for a slower laptime, but importantly the sliding around overheats and quickly destroys the surface, making matters worse and you’ve lost your opportunity for the optimum lap.
With such little meaningful running in representative conditions, the practice sessions at the first few Grand Prix and in particular Albert Park, are going to be really important to all of the teams. They still don’t really know how the characteristics of their cars will change in t-shirt and sunglasses conditions, let alone what the supersoft tyre does at all. The teams who did try that option here in Barcelona found it lasting for something ridiculous like three or four corners before it was degraded by the process I’ve described, simply because they couldn’t get anywhere near the required temperatures into it.
Any downtime in P1 or P2, unlike this week where they’ve had a chance to make up for it and recover, will cost teams dearly come Australia and that’s something McLaren and Lotus need to sort out and ensure doesn’t happen pretty quickly.