Formula One Suspension Set-Up for the Rain

F1 Cars Need Special Suspension Settings, Especially in the Rain

Apr 22, 2009

Two of the first three F1 races in 2009 were run in wet conditions. If the engineers had known it was going to rain, how would they have set up their cars?

Many items on an F1 car are adjustable to optimize the overall performance: suspension, aerodynamics, gear ratios, and engine settings, to name but a few. However, to achieve good lap times, the correct suspension and aero settings are critical.

Mechanical Grip and Aero Grip

The grip afforded by the tires is controlled by two parameters; mechanical grip, and aero grip (down-force). Although there is a certain amount of overlap between these two parameters, mechanical grip is generally controlled by the suspension settings. These settings will be established by the engineer based on prior knowledge of the track/car/driver combination, and the anticipated weather conditions.

To set a race car’s suspension specifically for wet conditions, the engineer will make allowances for the reduced grip available on the track. In dry conditions, the car will develop higher cornering speeds and the suspension will be set very hard accordingly – the engineer will not want the chassis to roll in the corners, for instance. But in the wet, the car will be traveling much slower and will generate less grip overall.

Softer Shocks

Ideally, the engineer would prefer fitting softer suspension springs to increase the mechanical grip, but as it will be necessary to increase the overall down-force, he may well leave the springs as per the dry set-up. However, the shock absorbers (dampers) will need to be softened both in compression, and in rebound.

As the car will not be generating high grip levels on corners, the anti-roll-bar (a device that limits the chassis from rolling in the turns) will also be softened. Some teams will disconnect the anti-roll-bars altogether.

To stop the car’s chassis from aquaplaning (floating on puddles of water), the ride height will be increased - this is the static distance a car is set above the ground. Normally, in dry conditions, the cars are set up to run as close to the track as possible as this makes the under-body aerodynamics work better and also lowers the center of gravity.

Increased Down-Force from the Wings

As the car will be traveling slower than in dry conditions, the down-force generated will be proportionately lower, therefore, the engineer will elect to increase the down-force generated by the wings. Also, as mentioned, when the ride height was increased, the overall down-force would have been reduced, and the engineer must compensate for this too when deciding on the wing angles.

As the top speed of the car will be less than in dry conditions, the gear ratios will need changing too. However, as the engines develop more power at higher rpm (revolutions per minuet), the gear ratios may not be changed in an attempt to reduce wheel spin – less power equals less chance of wheel spin.

In addition to all of these suspension and aero setting changes, teams will ensure that water cannot get into the electronic systems. This is particularly important in 2009 with the introduction of the KERS (Kinetic Energy Recovery) systems, where water could act as a conductor between the high voltage systems and the driver.

With optimization of the settings for wet conditions, the teams will be in good shape for the race, unless of course it dries out during the race!

The copyright of the article Formula One Suspension Set-Up for the Rain in Formula 1 is owned by John Glimmerveen. Permission to republish Formula One Suspension Set-Up for the Rain in print or online must be granted by the author in writing.