Front bib and T-tray explained: The F1 car part under FIA suspicion at US GP

The T-Tray and front bib on a Formula 1 car have been in the news, so we're breaking down their role on a car and what they mean for performance.

An intriguing aerodynamic development has stirred up in the F1 paddock, with the FIA vowing to take swift action at this weekend’s US GP.

The spotlight is now on the front bib – commonly known as the T-Tray – a key aerodynamic component located beneath the car. There were growing suspicions that one unnamed team had been altering the height of this element, adjusting its position to suit different phases of the race weekend. If true, this tactic could provide a significant edge on the track, but how exactly does the T-Tray function, what is its role in the car’s aerodynamics, and how might teams be manipulating it?

The T-Tray, also referred to as the splitter, sits at the front of the car’s floor, just behind the front axle. Initially, its purpose in Formula 1 was quite straightforward – it provided a mounting point for the plank that runs almost the entire length of the floor. This plank plays a vital regulatory role.

Since the early 1980s, teams have been required to maintain a flat floor relative to the reference plane, and the plank has been key to monitoring compliance with this rule. Even today, it ensures that the car’s ride height stays within legal limits during a race. Any excessive wear on the wooden plank serves as a clear indication that the car may have been running too low.

Over time, as aerodynamics became increasingly important to the overall performance of F1 cars, the T-Tray began to serve additional, more aerodynamic purposes.

Since the 2022 rule changes and the reintroduction of ground effect, the car’s floor has become the primary source of downforce, and teams devote significant attention to optimising this area.

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As the T-Tray is positioned well ahead of the car’s underfloor tunnels, its design greatly affects airflow behind it and how air enters the tunnels.

It also serves to split the airflow to the left and right, with a small percentage of air flowing beneath the plank’s lower surface. Engineers aim to use this opportunity to energise the airflow by creating vortices that later enter the underfloor tunnels.

These vortices not only help increase airflow speed beneath the car, lowering local pressure and directly boosting downforce, but also improve the efficiency of the diffuser and other rear-end aerodynamic elements.

In short, the aerodynamic efficiency of the car’s entire floor is critical to its performance on the track, and the T-Tray is the first element to influence the flow, dictating much of what happens behind it.

As we know, the ride height of an F1 car significantly affects its aerodynamic behaviour and performance.

Engineers are constantly searching for the optimal height that will allow the car’s floor to reach its full potential. However, track conditions and session types vary, especially when it comes to the difference between qualifying and the race.

Fuel load plays a major role in this – it affects the car’s weight, and consequently, its ride height. Since changing the car’s height between sessions is prohibited, engineers must find an optimal solution.

Therefore, even a slight adjustment to the height of the T-Tray can have a significant impact on underfloor aerodynamics. Lowering the T-Tray can also reduce the front wing’s height relative to the ground, making it more efficient. This change can alter the car’s balance, shifting it towards the front and potentially reducing understeer. Moreover, a lower splitter increases local downforce at that point.

On the other hand, raising the height of the T-Tray may help in other ways – for instance, bringing the car’s height closer to optimal when the fuel tank is full.

Of course, these are potential benefits for which we currently have no solid evidence of any teams employing. However, it is clear that manipulating the height of the T-Tray could give engineers greater flexibility in tailoring the car’s aerodynamics to suit a particular circuit or session type.

Rumours suggest that an unnamed team has cleverly designed their car to allow such adjustments from within the cockpit, by incorporating a simple spring mechanism. Given that cockpit inspections are routine before each track session, it is difficult for the FIA or rival teams to confirm this theory.

This latest tech row will undoubtedly be a hot topic of the F1 paddock at COTA, so stay tuned…

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