Why Piastri was over half a second slower than Norris in F1 Mexico GP qualifying

Nature abhors a vacuum, so naturally Oscar Piastri’s recent lack of pace compared with McLaren team-mate Lando Norris – stretching to a remarkable 0.588s in final qualifying for the Mexico City GP – has prompted fevered speculation.

Since the human brain is hard-wired towards pattern recognition, many theories centre around a problem with the car – either as a result of damage incurred during the campaign, most recently in the sprint round in Austin, or because McLaren is deliberately ‘nobbling’ Piastri to favour Norris. Ridiculous as the latter proposition is, the problem with conspiracy theories – no matter how improbably or even unhinged – is that they are inherently self-validating.

Sometimes a driver comes to believe there is something wrong with their car, and recent Formula 1 history is ripe with examples of teams appeasing fractious drivers by swapping monocoques. But McLaren team principal Andrea Stella is adamant that Piastri’s problem lies neither in his car nor his head.

“Every evidence, every piece of data, every indirect measurement of information we have tells us that there is no problem with the car, and we have no reason to suspect that that’s the case,” said Stella after qualifying in Mexico.

“Also the change of the chassis, I know that in the history of Formula 1 there is this topic of changing the chassis. I would change other components than the chassis, like the floor, the front wing, but in reality there is a rotation of parts, so it’s not like there is always the same parts on the car. So we have reasons to be reassured that there is no problem with the car.”

McLaren’s thinking is that Piastri and Norris have different skill sets, and Piastri struggles in low-grip conditions where the tyres begin to slide. There is lap time on the table if the driver can lean on the car a little more, whereas Piastri’s natural instinct is to keep it tidy and kill the slide. As a result he loses fractions of a second per corner, which compound into a bigger deficit at the end of the lap.

It’s counter-intuitive because too much sliding can cause the tyres’ surface temperature to spike, damaging performance. It’s a question of degree.

The Autodromo Hermanos Rodriguez is the least grippy track on the calendar, a factor of the track surface and the fact that the facility is little-used for the rest of the year. Dust, therefore, accumulates and, while protracted running clears it from the racing line, away from that line it remains on the surface to kill the grip of anyone running over it.

Also, while the track is bumpy on account of local geography – this used to be a lake basin, and groundwater extraction is causing subsidence of around 30cm per year in some places – the aggregate used on the asphalt surface is relatively smooth. Tyre grip is partly a factor of the tread pushing into the indentations in the asphalt; the smaller the gaps, the less micro-mechanical grip is generated.

Oscar Piastri, McLaren

Photo by: Sam Bagnall / Sutton Images via Getty Images

“The fastest car is also a car that needs to be driven in a certain way,” added Stella.

“Especially when you have conditions like here and to some extent in Austin, with hot tarmac, sliding tyres, and the way in which you generate lap time is a way that, I would say, comes relatively naturally for Lando and less naturally for Oscar. You know, Lando is the driver of going on low grip: end of the stint, when the tyres are quite worn, used, the grip is low, is where we see Lando doing green sector, green sector, green sector.

“Oscar, instead, is more of a driver of high grip, that’s where he can exploit his incredible talent. At the same time, we don’t have to forget that while we talk about the leader in the drivers’ championship, he’s not even finished the third season in Formula 1.

“So, experiencing situations like we have here in Austin is how you actually calibrate yourself as a driver. So Oscar, every session, is learning a little bit as to what you need to do, what you need to feel to say, ‘I’m fast now,’ in these specific conditions, which conversely are more natural conditions for Lando.

“Nothing to worry, I think it’s more a calibration exercise for Oscar. I’m sure this calibration will pay off.”

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– The Autosport.com Team