The FIA and Formula 1 management made changes to the aerodynamic regulations ahead of 2021 in a bid force a 10% reduction in overall downforce – enough they believe to allow the tyres to cope with the ever-increasing downforce the cars deliver.
The most significant contributor to the forecasted 10% drop in downforce is a set of new floor regulations. The cars see a diagonal cut in the floor ahead of the rear tyres, reducing the width at the trailing edge by 100mm on each side.
Red Bull Racing RB16B. Formula 1 Testing, Sakhir, Bahrain, Day One. Photo: XPB Images
 
Additionally, the rules prevent the designers from having any fully enclosed holes in the floor to manipulate airflow through slots, holes, and shaped aerodynamic furniture in that region. These changes decrease the floor’s working area used to generate downforce from under the car and reduce the team’s ability to seal the floor to work the diffuser as effectively as possible. AlphaTauri AT02 floor detail. Formula 1 Testing, Sakhir, Bahrain, Day One. Photo: XPB Images
 
Additionally, it will be harder to control rear tyre wake influence on the diffuser stream and control rejected air from the rear tyres without the slots, holes, and other aerodynamic fixtures seen in 2020. The loss of these features also reduces the control of the aerodynamic consequences of the varying sidewall bulge and contact patch squirt (loss ejected by the tyre as it contacts the ground).
Mercedes AMG F...