Why is Piastri losing to Norris?

      Authoritative expert Mark Hughes, writing in the British magazine Motor Sport, dispelled suggestions that McLaren were deliberately sabotaging Oscar Piastri’s car to help Lando Norris win the title. Hughes explained the Australian driver’s deficit to his teammate as a difference in driving technique and tyre work, which became especially apparent at the Mexico circuit.

      After two unremarkable races in which Oscar Piastri trailed teammate Lando Norris and lost the lead in the drivers’ standings, the most vocal and loudest section of Formula 1 fans, as expected, hurled wild accusations of team sabotage. How could a driver who had been as quick as Norris up to Austin suddenly start losing half a second or more a lap in two races running, they asked?

      In fact, such a speed difference is fairly easy to explain when you have telemetry and GPS data and an understanding of how tyres interact with the track, how that affects the car’s behaviour, and how that in turn makes each driver feel the car differently.

      As McLaren team principal Andrea Stella noted, both in Austin and in Mexico the asphalt had very low grip. Oscar Piastri simply could not adapt his driving technique to that surface as well as Norris did.

      They have completely different techniques, and on corner entry they load the car differently almost everywhere. But on those two tracks Piastri was about 0.5 seconds slower.

      If we look at the Mexico round in more detail, the main difficulty with the smooth surface at high altitude is heating the front tyres up for the first corner while avoiding overheating the rears by the final part of the lap. That is much harder to achieve than at other tracks requiring a similar compromise in car setup (Barcelona, Hungary, Abu Dhabi), because the ultra-smooth asphalt does not allow the tyres to get a good bite on the surface, so the mechanical grip that comes from tyre hysteresis (the tyre deforming while moving, which generates heat) is not very effective.

      All this puts additional stress on the tyre tread, which tends to overheat. As it overheats it transfers less load to the tyre carcass, which consequently remains cool and inflexible.

      Norris’s pole lap was 0.588 seconds quicker than Piastri’s lap that earned him eighth place. That difference is explained by Piastri losing 0.25 seconds in the first corner (the fronts hadn’t warmed up) and 0.343 seconds in the long, slow final corner (the rears were too overheated). In total, Piastri’s losses in those two corners relative to his teammate amounted to 0.593 seconds.

      They did the rest of the lap at an equal pace, because the configuration smooths out the difference in driving styles. Yes, Piastri lost time in the fast Turn 9, which is atypical, but overall he was faster through the slower sequence of Turns 4, 5 and 6.

      Piastri’s 0.343-second loss in Turns 16–17 is explained by greater understeer on entry, more wheel lock-up as power increased and, therefore, more excess oversteer on exit, which further overheats the rear tyre surface.

      Piastri simply doesn’t turn as effectively because his driving technique loads the front tyres differently. This is also visible in the time loss in the first corner. Approaching that corner, Norris partially lifts and overlaps that phase with the start of braking, whereas Piastri brakes later and immediately fully releases the throttle, not overlapping throttle and brake.

      In that phase Norris can rotate the car more on entry, which allows him to carry more speed through the corner. That is where the noticeable time gain occurs. Norris carried apex speed through the second corner, the slowest part of the sequence, at 112.6 km/h, whereas Piastri did it at 101.4 km/h. On that section Piastri lost a quarter of a second.

      Mexico was simply a more extreme example of what we usually see at the start of every race weekend, when on a dusty track not yet covered in rubber Norris is invariably quicker than his teammate. As grip improves over the weekend, the car copes better with the sharper load changes associated with Piastri’s entry technique, and Oscar catches up with or passes Norris.

      “Over the previous two weekends I had to drive the car completely differently,” Oscar Piastri said after the race in Mexico. “But it was hard for me to realise because in the previous 19 races everything worked well… Our car hasn’t changed for a long time, it’s just that Lando feels more comfortable in the cockpit over the last few races.”

      That is the reason for the deficit. Forget the conspiracy theories.