The FIA authorizes the return of mullets in F1 now, to prepare for 2026

The new Formula 1 regulations that will come into force in 2026 continue to raise concerns within the FIA itself. Aware of the challenges ahead, the International Automobile Federation has decided to introduce new principles to best assist teams in preparing.

A very strict regulation outside free practice during a Grand Prix

In Formula 1, it is almost impossible to drive with the car of the current year on a real circuit for several years, except in a well-defined framework. These are test sessions organized at the beginning of the season with all the teams and their new car, or promotional days (limited to 2 days per team per season).

The FIA has also set up test sessions for tire manufacturers to develop their single-seaters, but these are not dedicated to team development. And that’s it. So, to facilitate the training of young drivers, it is possible to drive with single-seaters that are 2 seasons old or more, but only with a young driver.

This very restrictive regulation is worrying for 2026 and better preparing for significant technical changes.

Tests with “mule” cars

The FIA World Motor Sport Council has introduced a new rule allowing 10 days of mule cars testing this year. This decision echoes the remarks of Mario Isola, head of tire development at Pirelli, who had rejected the development of new mule cars due to their inconsistency with the 2026 regulations.

« It is impossible to create a mule car with similar characteristics. We will not have smaller cars. We can save weight – instead of doing long relays, you can reduce the fuel level just to simulate the weight. But for the rest, it is impossible because there is no active aerodynamics.

In response, the FIA declared that all teams will be able to use chassis built according to the technical regulations of one of the four previous seasons (2020 to 2023) as a basis for the mules and update their machines with various settings in order to better replicate the requirements of upcoming regulatory changes.

This includes the single-seaters from 2022, much heavier than those from 2026 (798 kg for the 2022 car compared to 768 for its 2026 counterpart) and using ground effect, hence Mario Isola’s concern about the relevance of the data collected. However, he hopes to obtain useful information, especially to prepare the tires for 2026.

« We need these figures to characterize the stress exerted on the tires and then design the tire. » These tests therefore appear essential for the FIA in order to prepare for the upcoming events in the best possible way.

« Mulets (TMC) trials are defined as any track time, not part of a competition, in which a competitor registered in the championship participates using cars designed and built according to the technical regulations of one of the four calendar years (2020 to 2023) preceding the championship calendar year (2024), but properly modified to test future products of the designated tire supplier or to test components or systems for future championship seasons. »

« Cars must include and be limited to the minimum modifications necessary to test development tires or to test components or systems for the FIA for future championship seasons, as determined by the FIA » states the FIA regulation, allowing teams to use different aerodynamic devices to see which one will be most suitable for 2026.

Mule cars already tested before the 2017 season

This is not an innovation, donkey cars having already been used in 2016 to prepare for the new 2017 regulations, which introduced wider front tires and wings. This had allowed teams to create more powerful aerodynamic devices to generate more downforce.

« It is a situation similar to the one we encountered with the mule cars when we were developing the 18-inch tire, for example, or in 2016 when we were developing the wider tire for 2017. We were doing it with mules that were not entirely representative, » explained Mario Isola, emphasizing the importance of the data obtained for the 10 teams on the grid.

The permission to use the 2022 models can prove useful, as they feature the ground effect concept, allowing single-seaters to follow each other more easily, a criterion that the FIA wishes to continue in 2026, according to Jason Somerville, aerodynamics manager within the federation.

» The main objective of the aerodynamic rules for 2026 is really to focus on restoring performances for following cars. We want great races; we want to ensure that cars can follow closely. The 2026 rules are an opportunity for us to reset the baseline of cars so they can race together.

In parallel, Pirelli will carry out tests concerning the 2026 tires, which will be slightly narrower and will have a new compound with the introduction of the C6 tire, one step softer than the C5. Many trials are therefore awaiting the 10 teams of the grid to be ready for the 2026 season, which promises to be exciting.

What does the regulation say?

The new article 10.10 of the 2024 sports regulations specifies:

« Test mules cars (TMC) are defined as any track session, which is not part of a competition, in which a competitor registered in the championship participates (or in which a third party participates on behalf of a competitor or supplier of an approved powertrain group), using cars designed and built to comply with the technical regulations or the technical regulations of one of the four calendar years preceding the championship calendar year, but appropriately modified to allow the designated tire supplier to test its future products on track or to allow the FIA to test components or systems for future championship seasons. No competitor may sell or make available such a car to a third party without prior authorization from the FIA. »

« Cars must include and be limited to the minimal modifications necessary for tire development testing or for testing components or systems on behalf of the FIA for future championship seasons, as determined by the FIA. »

Please note that only drivers with more than 500 km of driving in F1 will be able to drive on these days.