Small separations in its construction, caused by damage sustained from running across the Losail circuit's high kerbs, had triggered concerns about potential failures in the race.
A hastily revised configuration of track limits, allied to an emergency 10-minute practice session to get used to the new layout was the first step in a weekend that could now have a totally different feel.
So ahead of what could be a mandated three-stop Qatar GP, we look at the key issues at stake in terms of what has happened so far, and where things could lead from here.
What has caused the tyre problem?
Pirelli discovered the problem after routine analysis of sets used in FP1 and returned by the teams, which as on every Friday were cut up and examined.
As the company's F1 boss Mario Isola noted, his engineers "saw an indication that there was – in the construction of the tyre on the sidewall – a small separation between the carcass chord and the topping compound."
Further investigation indicated that it was caused by the Losail kerbs, especially those in the high-speed Turn 12-13 section, where drivers were spending a relatively long time running along them.
A perfect storm of the time spent on the kerbs, the high g-loadings in the corner sequence, the harshness of the kerbs and their edges plus the frequency put through the tyres as they bumped across them created the problem.
Isola explained: "It's not just the geometry of the kerbs, because these kerbs are used in many other circuits. It's the time and the speed they stay on the kerbs that is important.
"So, here, during the lap, all the drivers are spending quite a lot of time at high speed on the kerbs, and this is damaging the construction."
Is this a new phenomenon?
Tyre damage was caused by the Qatar kerbs in 2021, and what occurred was fully investigated by Pirelli after the race weekend, with the results submitted to the FIA.
However, Isola stressed that the specific problem discovered on Friday night was a new one, noting "I can add that we never found this issue. That's why we informed the FIA."
The issue is caused by the physical pounding that the sidewalls were taking.
"In this case, we don't have an issue with the construction," said Isola. "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.
"Because the chord is giving you a certain resistance, and then you push in the direction of the chord and the compound is subject to this continuous impact and then you break it."
He added: "If you continue to run on the same tyre, then these small fractures can continue, and then you can reach a point where you have a loss of pressure. And if you have a loss of pressure, obviously, you run flat."
Is this a repeat of the tyre failures from 2021?
Pirelli is keen to point out that 18-inch tyres are in use this year, with a low-profile sidewall, whereas in 2021 it was still using 13-inch tyres.
That factor alone means that the two situations are different, although Isola said the current tyres are not inherently more vulnerable.
"The smaller sidewall for sure is not helping," said Isola. "Because you have less opportunity to absorb the hit.
"But in general, when we made some specific tests on the 18-inch tyre, we realised that the level of resistance of the construction was in line with the 13 inches. So, we are not saying that the 18-inch tyre is weaker compared to the previous tyre."
The kerbs are also ostensibly different, although Isola noted that they act like those in use two years ago.
"The geometry of the kerbs we have here is similar to the geometry of the kerbs that we had in 2021 [with] the second row of the kerbs," he said.
"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 kerb, and they go down."
What is wrong with the Qatar kerbs and why can't they be changed?
Losail made its F1 debut in 2021 by virtue of being able to organise a race at short notice during the ongoing COVID-19 disruption.
But this year marks the first round to be held at the venue as part of Qatar's 10-year host contract. As such, the circuit has undergone extensive upgrades. Aside from a resurfacing, the kerbs were revised.
Although these new kerbs have been constructed to FIA specification, their raised 50-millimetre pyramid-style outer edge has created high-frequency interference with the tyres.
Drivers are running over them faster and for longer compared to other tracks, according to Pirelli. As the cars wash out wide to the permitter, the inner sidewall drops over the kerb edge and takes repeated impacts.
The FIA assessed modifying the kerbs on Friday night as the critical tyre problems were identified. It was considered whether they might be ground down, but the governing body's single-seater director Nikolas Tombazis reckoned there were too many that were too solid.
As an alternative, the white lines defining track limits have been brought in by 80cm to draw drivers away from the kerb edge.
Tombazis told Sky Sports: "Safety is absolutely our number one priority here. We did consider modifying the kerbs but in the time we had from last night, very late at night, until today, that would not have been possible. It was not one or two single kerbs. It was quite an extent.
"They would have all had to be filed off and that's very hard concrete. That would not have been possible. So, on that basis, the next thing we got was to actually get the cars to stay a bit further away from the kerbs, which is what we've done by the change to the white line."
Why potentially make the Qatar GP a three-stop and not a two-stopper?
With Pirelli and the FIA concluding that a safe tyre life for the Qatar Grand Prix track is 20 laps, it would be logical to suggest that Sunday's 57-lap race could be made a mandatory two-stop to ensure all drivers fell in line.
However, should F1 go ahead with forcing a maximum 20-lap tyre life, then it will also impose a three-stop race. It may seem strange to need to put both actions in place, but Isola says there is logic behind it.
"It's 57 laps and if you impose a two-stop, the risk is to have all the cars on the same lap coming in," he said.
"That makes confusion. So, if you impose a maximum number of laps at 20, but three stops, you have the flexibility to play around this."
Will the teams get any extra sets for the GP?
The potential for a mandatory three-stop race means that some drivers may find themselves short of the best compound for the race if they are forced to cycle through them.
Matters also will not have been helped by the fact that teams had to conduct an extra 10-minute practice session on Saturday morning.
But Isola has said there is no scope for any extra tyres to be handed out, even on safety grounds, because there are not enough spare sets on the ground in Qatar.
"We don't have a number of tyres that can give us the possibility to fit an additional set of any compound," he said.
"We have spare tyres, but we cannot give one medium to you, one soft to him and one hard to another one.
"But I believe that, with the current format, they have plenty of tyres in their allocation. And don't forget they start with 12 sets, and they have only to return two."
What process will Pirelli go through ahead of the grand prix?
A final decision on whether or not extra safety measures will be imposed for the Qatar GP will be made on Saturday night.
With the issue of tyre separation only being noticeable once tyres have been cut open and examined under the microscope, there is little further analysis that can be conducted before the end of the sprint race.
"After qualifying there is nothing we can do because the teams are not going to return any tyres," Isola said.
"After the sprint they are obliged to return a set of tyres with the highest number of laps. So probably we will have 20 sets of tyres with 19 laps and obviously we will cut them and we will run the same analysis we did yesterday in order to understand how is the damage.
"[We will also see] if there are differences across the cars, if these new track limits are working well and so on, and then we will give the information to the FIA in order to take the decision for tomorrow."
What will happen after this weekend?
The short answer is investigations will continue. The FIA and Pirelli ran simulations at Losail in 2021 but this data is now outdated since F1 wheel rims have grown from 13 to 18 inches to reduce the profile of the sidewall. The kerb design has also changed.
Therefore, once this weekend is complete and the immediate firefighting finished, fresh research must be completed. These will help establish with confidence the reasons behind the tyre issue, and to work on permanent solutions.
Isola said: "After this weekend, we will continue to analyse the tyres: usually as a normal procedure. On top of the analysis we do here on track, we send back to Milan and to our indoor test department a good number of tyres for additional analysis that obviously we cannot do here.
"As soon as we have the result, we will inform, we will prepare a report to inform the FIA of any additional findings after the race."
The FIA is also assessing how it can end the issue of track limits, which remains high on the agenda, for good. Gravel traps and changes to circuit infrastructure are high on the list.
Simultaneously, initial investigations are under way to assess what role technology might play in speeding up how track limits are monitored and enforced to avoid delays in lap times being deleted.
By Adam Cooper, Matt Kew and Jonathan Noble
