Technical Draft: The Formula 1 Wet Weather Set Up

Formula 1 wet rainmaster

The weather forecast for the 2021 Styrian Grand Prix at the Red Bull Ring in Speilberg includes a high likelihood of a dry qualifying session followed by a wet race.

Finding lap time in the wet in a Formula 1 is so much more than just being about who is the Rainmaster behind the wheel.

It is about engineering and compromises.

In fact, even if the best rain driver on the grid is behind the wheel, if the setup on the car is wrong, lap time will not be found.

So, just how will an F1 team set a car up to be fast in the wet?

Before considering this, it is important to acknowledge that in modern F1 unless qualifying is conducted in wet conditions knowing that the race will also be wet, it is highly likely that a wet specific setup will not be used.

Firstly, there are certain changes that would have been made in the past that are no longer allowed. For instance, gear ratio and engine maps are obvious changes that give good performance benefits in wet conditions that are no longer allowed.

Obviously and simply, wet conditions reduce grip. The tyre contact patch is compromised by water, and cornering speeds are reduced as a result.

An F1 wet setup is essentially all about regaining back as much of that grip as possible.

Front and rear wings are generally set with the main plane chord axes at much larger angles to the horizontal in a wet set up. The aerodynamic strategy of an F1 car in the wet is all about maximising low speed grip.

It is also important to remember that at lower cornering speeds the aerodynamic load provided by the underfloor is significantly less and this also changes the centre of aerodynamic pressure of the car. This puts more emphasis on the wing settings and the need to increase the load they provide.

A contemporary F1 is classified as flat bottomed and is more prone to aquaplane in wet conditions at high speed. An extremely critical part of a wet setup is an increase in overall ride height, both front and rear.

Not only will more ground clearance reduce the risk of the tyres surfing on ground water, the risk of bottoming at high speed is also reduced. Bottoming in an F1 at high speed in the wet can result in an instantaneous and catastrophic loss of grip.

Mechanical methods of pursuing more grip in a wet setup include increasing negative camber and toe-in, particularly at the front. Spring rates are reduced, and dampers are softened in both bump and rebound, specifically the low-speed adjustment ranges.

It is not unusual for specific damper valving for wet conditions to be used, the ‘wet specials”. Importantly, and because of the reduction in cornering speeds in wet conditions, lateral compliance is significantly reduced.

Too much roll control in the wet can be detrimental and reduce lateral grip. Roll bars are softened to minimal and quite often rear roll bars will be disconnected completely.

One of the more important impacts of wet weather on an F1’s performance is significantly increased braking distances.

Lower temperature (softer) brake pad compounds, particularly at the front might be used and brake bias adjustments made reducing the front bias towards the rear. In years gone by even wet weather specific rotors would be used.

There are specific wet driving techniques the drivers will use in the wet, but without delving in detail into those, there are two techniques associated to the engineering specifics. In wet conditions drivers will use different braking techniques such as cadence and trailing braking to minimise axle lock up and ensure progressive weight transfer to the front of the car as it would be set up softer.

Wet conditions obviously require different tyres, and the Pirelli intermediate and full wet tyres serve that purpose very well. Tyre pressures are also reduced to help improve the grip that they provide.

Interestingly in the past, the choice of wet weather tyre used was at the discretion of the team and some would have a member on staff who was an expert in the black art of carving wet weather patterns in very soft compound slicks. These technicians were highly desired, often poached by other teams and paid very well.

In accordance with the current sporting regulations cars go into Parc Ferme conditions after qualifying and setup changes are not allowed prior to the race. Unfortunately, this applies even if a race is declared wet.

Of course, the use of wet tyres is allowed, but the only setup change of substance allowed if a race is declared wet is to brake ducts.

In the past the post-qualifying Parc Ferme conditions did not exist and when a race was wet not only were we privileged to watch rainmaster drivers demonstrate their superior wet weather skills, but also marvellous demonstrations of engineering agility as the teams endeavoured to adapt to a wet setup the best in a short timeframe.

It seems most unfortunate and to the detriment of the sport that modern F1 no longer allows us to witness those engineering challenges play out.