Following the standard analysis of tyres used during Free Practice 1 yesterday, in which tyres that have been used for approximately 20 laps are examined by Pirelli to check various safety parameters, a separation in the sidewall between the topping compound and the carcass cords on many of tyres that were checked was discovered.
It is the view of the FIA and Pirelli that 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.
The following actions will be taken on safety grounds in response to this issue:
- Track limits at Turns 12-13 will be revised.
- There will be a 10-minute Practice Familiarisation Session, scheduled to start at 16:00 local time, following the revision of the track limits, to allow drivers to adjust to the changes. The Sprint Shootout will therefore start 20 minutes later than scheduled (16:20 local time).
- There will extensive tyre analysis following the Sprint (19 laps), to decide whether further action needs to be taken ahead of the Grand Prix.
- In the event the problem is still evident, we will be issuing the following directive for Sunday’s Grand Prix, on safety grounds:
4.1 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.
4.2 All drivers will be obliged to perform at least three tyre-change pitstops during the race.
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.
UPDATE:
Due to the frequency of Safety Car interventions in yesterday’s Sprint, the tyre data available for analysis by Pirelli was insufficient to add to that already undertaken following previous track sessions.
In some cases, tyres that were analysed from the Sprint did show the initial onset of the separation in the sidewall between the topping compound and the carcass cords of the tyres.
As was the case in Free Practice 1, 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.
As a consequence, it has been decided by the FIA and Pirelli and after consultation with the teams on safety grounds, the following measures will be implemented for today’s Qatar Grand Prix:
- A mandatory limit of 18 laps of total tyre life per set will be imposed.
- The life of already used tyres will be taken into consideration.
- The FIA and Pirelli will communicate to the teams the remaining available laps for each set of used tyres at their disposal for the race and the criteria used to calculate that number.
- There is no direct mandate for at least three tyre-change pitstops during the race, however this will be a consequence of the above guidelines should the race run its entire race distance.
- Any car deemed to have exceeded the tyre life lap limit will be reported to the Stewards as being run in an unsafe condition.
- This information will be formally communicated to the teams in the Race Directors’ notes and further updates issued as required.