The technology on show in Abu Dhabi F1 testing ahead of new-look 2022

Testing with these cars has been ongoing throughout 2021 but this is the first time all of them have been used together, allowing a much larger pool of data to be collected that can be used by the tyre supplier and the teams.

To qualify as a ‘mule’ car, teams were required to make the necessary changes to allow the new wheel rims and tyres to be fitted, which has mainly resulted in a new suspension design and brake ducts. It wasn’t specified as to what vintage the car had to be and so there’s an array of choices from the teams, as will be discovered in the gallery below...

Click on the arrows in the images to scroll through them

A look inside the brake drum assembly of the 2019 Mercedes W10 that’s been repurposed for the test. The teams will be much more limited in the aerodynamic assistance that can be provided in 2022, with more of a brake cooling focus seen here. You’ll note how much larger the end fence is though, in order that it marries with the wheel rim well.

The much larger brake drum can be seen here as the team prepares the W10 for action.

The brake drum fitted to the W10 mule car which has been extended to take up the entire space within the wheel well – note how the inlet has been blanked off where ordinarily it would feed internal pipework that serves an aerodynamic purpose.

The AlphaTauri AT01 mule car is being run with just an enlarged brake duct fence for comparison.

McLaren, on the other hand, has opted for the full-size brake drum and some channels on the end.

Aston Martin has opted to run this year's car in the mule configuration and in a similar fashion to AlphaTauri, have only increased the size of the brake fence.

McLaren has also opted for this year’s car as the base for their mule, owing to the Mercedes power unit deal which would have made life difficult on an older car – here it is with the wheel rim covers on the rear of the car.

Meanwhile, Ferrari has opted to create a mule car from the 2020 challenger, the SF90, with the front brake duct assembly having a gentler transition from the larger end fence into a larger but not maximum sized brake drum.

Another angle of the Ferrari SF90 mule car’s front brake drum shows some pipework is routed to the outer ring of the drum for aerodynamic assistance.

Running without the front wheel covers on their car we can see those ducts through the wheel spokes.

Alpine has really wound back the clock and have repurposed the Renault RS18 chassis for its mule car, even using the front and rear wings from that era. The brake duct appears to have simply had a collar added to close-off the end fence.

The 2018 specification front and rear wings can be seen more clearly in this image, with the cascades on the front wing and endplate louvres on the rear wing the distinguishing features that would become outlawed in 2019. Also note the team is not using the outer wheel rim covers.