How did the tyre drama unfold in Qatar?

Following the opening day at the Qatar Grand Prix on which everything looked normal, Formula 1’s governing body the FIA revealed that the sport’s sole tyre supplier Pirelli discovered safety issues with their products at the Lusail track. F1Technical's senior writer Balázs Szabó reports on the unexpected issue.

The Milan-based tyre supplier carried out their usual tyre analysis after yesterday’s qualifying session, putting focus on the tyres that had been used for approximately 20 laps. During this process, Pirelli’s mechanics cut several tyres in pieces in order to perform in-deep analysis and measurements that are not possible by only examining the outer surface.

While analyzing the inner structure of the tyres, Pirelli found damages between the topping compound and the carcass cords. Although the damages were so small that they could not be realized by the naked eye, Pirelli’s Director of Motorsport Mario Isola reported the case to FIA’s Single Seater Director Nikolas Tombazis.

With no similar issues having been experienced during the 2023 F1 season, Pirelli suspects that the problem is track-specific with the Losail kerbs pinpointed as the main reason for the issues. When F1 last visited Qatar in 2021, several drivers – including then Mercedes driver Valtteri Bottas – suffered punctures which were also put down to the high kerbs at the Losail circuit. The high pyramid kerbs at Turns 12/13/14 have been highlighted as the most severe parts of the track which cars hit under heavy g-loading.

The FIA and Pirelli believe “a significant number of additional laps on these tyres could result in circumferential damage of the tyres with subsequent air loss, and tyres analysed with lower lap numbers showed a much-reduced extent of the issue.

“This issue has likely been caused by the high-frequency interference between the tyre sidewall and the 50mm ‘pyramid’ kerbs used extensively at this circuit, aggravated by the propensity to ride those kerbs.”

Isola stated that the kerbs punish the tyres in a way that is not experienced on any other circuit: "The issue is – to give you an [explanation] that is not a lot technical but probably clearer – it is like if you take a hammer with a pyramid at the top, and you hit it against the sidewall for 100 times per second for a long period.

"The compound is the weaker part. You have the chord of the carcass that is made with textile material and is a lot more resistant. So, it’s not a matter of fatigue. Fatigue is when you have the construction with fatigue [and] also the chord is affected.

“In this case, we don’t have an issue with the construction. It’s just the fact that you have a repeated impact on the sidewall that is affecting the resistance of the compound, localised where you have the chord,” Isola is quoted as saying by autosport.com.

Ahead of the Sprint Shootout, the FIA announced an additional practice session plus new safety measures with further possible steps announced if the situation does not improve on Saturday.

The track limits at Turns 12 and 13 have been revised which prompted the FIA to slot in a ten-minute practice session ahead of the Sprint Shootout to give drivers the opportunity of getting used to the new track limits.

After today’s Sprint race, Pirelli will conduct an extensive tyre analysis to decide whether further action needs to be taken ahead of the Grand Prix.

In the event the problem is still evident, the FIA will be issuing a directive for Sunday’s Grand Prix, on safety grounds. It would mean that the tyre life parameter must not exceed 20 for new tyres used in the race. This number would rise to 22 for any used tyres fitted in the race, to account for in-out laps in qualifying. Furthermore, all drivers will be obliged to perform at least three tyre-change pitstops during the race.