Tag: Pirelli

The Qatar Grand Prix will include maximum stint lengths of 18 laps to ensure tire integrity after concerns over curb strikes on Friday.

Small damage was identified during Friday practice that was judged to have been caused by the severe edge of exit curbs at circuit corners, and the amount of time cars run on them at high speed. While there were no failures, Pirelli noticed the initial signs in tires that had completed around 20 laps, so changed the track limits to try and keep them off the edges of curbs at Turn 12 and Turn 13.

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As the Sprint was an interrupted race with multiple Safety Car interventions, Pirelli felt it didn’t have enough data to be certain the problem has been removed, and in some cases, tires that were analyzed from the Sprint did show the initial onset of the separation in the sidewall between the topping compound and the carcass cords of the tires.

As a result, the FIA and Pirelli has agreed with the teams that it will mandate an 18-lap maximum tire stint for new tires for the race.

Used tires will be taken into account based on how many laps were completed at high speeds rather than cool downs, in and out laps in qualifying and Safety Car laps, and their permitted life communicated to each team by the FIA and Pirelli. Any car deemed to have exceeded the tire life lap limit will be reported to the stewards as being run in an unsafe condition.

While the stint lengths will lead to all teams needing to make at least three stops if the race runs its full distance under green flag conditions, the potential for interruptions, reduced laps and lapped cars means a three-stop race has not been directly mandated.

Pirelli has explained that changes to the curbs and the time drivers are spending on them have created indications that there could be safety issues at the Qatar Grand Prix.

The FIA has moved the track limits on the exit of Turn 12 and Turn 13 inside the existing exit curb by 80cm to prevent drivers running over the highest part of the curb that stands at 50mm. That’s in response to small initial hints at damage that were discovered by Pirelli after Friday practice, with the tire supplier concerned that use of the tires in the same way for more than 20 laps could lead to a construction failure in the race.

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Pirelli’s head of motorsport Mario Isola says the discovery was made during the standard post-session checks on Friday night and action had to be taken due to the potential safety permutations.

“Starting yesterday after free practice, as usual we collect several sets of tires,” Isola said. “They have to return one set of tires they used during free practice. We analyzed the sets. We saw an indication that in the construction of the tire on the sidewall, there was a small, small separation between the carcass cord and the topping compound.

“Obviously then we went deeper into the analysis, and this is due to strong impact against, or repeated impact against something. We believe that it is an impact against a curb. The geometry of the curbs we have here is similar to the geometry of the curbs we had in 2021, the second row of the curbs. And in 2021, we had a similar issue.

“So once we have seen this indication, obviously the first step was to inform the FIA to make them aware and find a solution. Maybe it’s because yesterday in free practice, all the drivers were running wide, they had low grip, and it was difficult to find the real line on the track. But our duty is to inform immediately if there is a potential issue. So with tires that we used yesterday and we analyzed were in the range of 20 laps, there is just the initiation (of an issue).

“But tomorrow, the race is 57 laps, and that means we that we need to understand better after the Sprint if with this additional track limits decided by the FIA, the problem is fixed or not. Probably the corners that are stressing the tire the most are Turns 12, 13 or 14. We have to spend a lot of time on the curbs.

“It’s not just the geometry of the curbs, because these curbs are used in many other circuits. It’s the time and the speed of staying on the curbs that is important. So here, during the lap, all the drivers are spending quite a lot of time at high speed on the curbs, and this is damaging the construction.”

The new track limits will remain in place for the rest of the weekend but if analysis after the 19-lap Sprint race show the issue to still be developing then maximum stint lengths will be imposed for Sunday’s race, as well as three mandatory pit stops. The choice of three stops rather than two has been made to ensure strategic variability is possible, rather than all teams being locked into the exact same stints. 

F1 races in Qatar two years ago and Isola says the 13-inch tires that were used in 2021 were not necessarily more resistant to the issue than the current 18-inch specification, but that the way the curbing has changed in the two years since has created the problem.

“A smaller sidewall for sure is not helping this effect, because you have less opportunity to absorb the heat. But in general, when we made some specific test on the 18-inch tires, we realized that the level of resistance on the construction was in line with the 13 inches. So we are not saying that the 13-inch tire is weaker compared to the previous tire.

“The point is that in 2021, this was the second row, and so when they were going out, the first row was 25mm, and the second row was 50mm. Now we have only one row that is 50mm. So they jump over the curb and they go down. That’s probably why we found out this issue in free practice, or luckily, we found out this issue in free practice.

“I believe it’s a good example of predicting an issue, and also working with the other stakeholders in order to avoid any safety issues during a race. Better to discover in advance.

“Just to be completely clear, if I cut a tire and I show you the section, you cannot see any damage. It’s so small, that obviously we can find the damage with a microscope. So it’s not an issue that here I’m saying, ‘guys pay attention because we have a big issue’. No. It’s an indication, but obviously we cannot ignore it. That’s why I reported what we found after our analysis.

“I don’t want to talk about fault. There is an issue and we have to work together to fix the issue. Then obviously you learn from issues and for the future we have to find a better process to anticipate it. But it’s important that if there is an issue that is not predicted then we have a system that is happening before we have any tire issue on track and we can fix it, even if we have to change the schedule or the track limits or whatever.”

The Qatar Grand Prix schedule has been changed to allow an extra practice session on Saturday ahead of the Sprint Shootout, while maximum stint lengths and a mandatory three-stop race could be imposed due to tire safety concerns.

Following Friday’s practice and qualifying session, Pirelli carried out its usual analysis, and in “tires that have been used for approximately 20 laps” a separation in the sidewall between the topping compound and the carcass cords on many of tires that were checked was discovered.

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“It is the view of the FIA and Pirelli that a significant number of additional laps on these tires could result in circumferential damage of the tires with subsequent air loss, and tires analyzed 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’ curbs used extensively at this circuit, aggravated by the propensity to ride those curbs.”

The curbs are new for this year’s race compared to the only previous visit in 2021, while the track has also been resurfaced, and drivers were previously concerned about floor damage if they ran too far wide.

To try and negate the issue, the track limits will be revised at Turn 12 and Turn 13 – where drivers have been running onto them at high speed through the three-part left-hander – with the white line on the exit brought in by 80cm. The gap from the existing exit curb to the new track limit will be painted to make it clear visually for the drivers.

There will therefore be a 10-minute practice session at 16:00 to allow drivers to familiarize themselves with the new limitations ahead of the rest of running on Saturday. That was the original time the Sprint Shootout was due to start, so the start of that session will now be delayed by 20 minutes until 16:20 local time.

Turn 14 will also be monitored closely – as well as the exits of other corners – to see how wide drivers are running, but on Friday it was only 12 and 13 that saw the furthest extreme of the curb used regularly.

The FIA says “there will extensive tire analysis following the Sprint (19 laps), to decide whether further action needs to be taken ahead of the grand prix,” and if the problem is still evident then on safety grounds a directive will define the maximum stint length for a new set of tires to be 20 laps on Sunday (or 22 laps for a used set to allow for in and out laps in qualifying), and a three-stop race will be mandatory.

“Pirelli and the FIA will carry out extensive research and simulations in order to establish with complete confidence the reasons behind this issue, and to work on solutions to avoid it in the future,” the governing body added.