The factors influencing Mercedes' challenging Bahrain GP weekend

Why the surface at Sepang posed challenges beyond just tyre performance

Two key aspects link the track surface to the car, with the most apparent being the relationship between the road and the tyres. The roughness of the circuit significantly contributed to excessive tyre heating, as the interaction between the tyre and the surface exerted additional strain on the tyre.

When the tyre contacts the road, it deforms elastically—implying that the tyre will revert to its original shape once the load is removed. This effect is intensified by the track surface; in places like Sepang, where there are numerous gaps in the surface, the tyre partly fills these voids. 

While this can enhance grip through the mechanical movement of the tyre, the loading and unloading (known as hysteresis) of the contact patch generates additional heat as waste energy. As the tyre deforms more to occupy those gaps in the road surface, the heat generated on the tyre's surface increases.

The second influencing factor, which has an aerodynamic dimension, was alluded to by McLaren team principal Andrea Stella. F1 vehicles not only utilize aerodynamic components to generate load but also to create specific airflow patterns and enhance the efficiency of the car's operation.

On a racetrack, the roughness of the surface must be taken into account, as it can impact the airflow beneath the car. No circuit is perfectly smooth, and teams likely have some understanding of the surface roughness to integrate into their simulations.

Andrea Kimi Antonelli, Mercedes

In a computational fluid dynamics (CFD) simulation, the "domain" walls at the bottom will have a frictional coefficient applied to ensure the accuracy of the flow field. Wind tunnels may also employ textured belts to replicate a similar impact.

However, a unique track surface will result in a different interaction with the airflow beneath the car. If you visualize that airflow being accelerated to help generate downforce, one can infer that the surface texture will influence how this flow behaves. The boundary layer —the theoretical immediate layer of a fluid surrounding a surface —will alter and could lead to effects such as turbulence due to separation.

Teams possess a wealth of data regarding Singapore, making the assessment of the car's relative performance —from both tyre and aerodynamic perspectives —much clearer.

Lord also addressed Russell's power unit failure in Malaysia, noting that the Mercedes power unit had experienced a mechanical malfunction but still required further investigation to identify the cause.

"From our initial investigation, after retrieving the car and conducting a preliminary inspection, it's evident there was a mechanical failure on the power unit," he stated.

"We still need to pinpoint the exact root cause, but the impact was clear for everyone to see. It was a significant setback for the team, costing 15 points, but particularly disappointing for George, who was on track for a very strong podium finish."