Car Setups: Playing With Physics

So, qualification is over, and you have done everything to set that perfect lap time. Braking late, maximum speed through the corner, barely exceeding track limits. Only P10? But I pushed the car to its limits! Well… you might have, but what if you had decreased your tire pressure, stiffened the suspension, or decreased the rake angle?
Racing cars are very complex machines. Apart from the fact that every car behaves differently, two equal cars may behave differently as well, depending on their settings. The collection of settings is known as a car setup, a term widely used in real-life motorsports, but also in simracing. In this blog is discussed what car setups are exactly, and how they can make you go faster around the (virtual) track.

The basics of car setups

Let’s get one thing out of the way: there is no specific car setup that is the quickest or which works the best for everyone. For example, a setup designed for hot laps (setting the quickest lap time possible) will not always work for an endurance (long-distance) race. Besides that, weather and time of day play an important role as well.

Parameters

A car setup consists of many different parameters. It is important to understand how certain parameters influence the behavior of the car. Changing one parameter may affect the complete system and behavior of the car! On top of that, certain effects will have to compromise for others. For example, compromising speed for better handling.
Opening the car setup menu reveals an overwhelming amount of settings that can be adjusted. The ten most important parameters (both in real-life racing and simracing) are selected and explained below.

Tyre pressure, camber, caster and toe :

Tyre pressure affects the contact area with the road surface. Increasing tyre pressure will increase grip, but will increase tyre temperature and decrease tyre life and fuel efficiency. The last three parameters have to do with the alignment of the wheels. Camber is the angle between the vertical axis of the car and tyre. For example, negative camber improves handling in corners but increases tyre wear. Toe is quite similar but in a horizontal direction. Increased toe-in will result in reduced oversteer (breaking out of the rear wheels, a.k.a. drifting), increased toe-out in reduced understeer (breaking out of the front wheels). Caster is the angle between the vertical axis of the wheels and the steering axis and will influence the directional control (precision and effort) of steering.

Springs and anti-roll bar:

These are the main components of the suspension. Springs absorb the energy caused by the vertical displacement of the wheels. Stiffer springs reduce ground clearance, increasing aerodynamics, and decreasing body roll. Softer springs however increase contact with the ground and provide more grip. An anti-roll bar is a bar connecting the left and right suspension, decreasing body roll caused by the displacement of the weight of the car (centrifugal force) while cornering. A rear anti-roll bar reduces oversteer, a front anti-roll bar reduces understeer.

Ride height, rake angle, rear wing, and front splitter:

These parameters influence the aerodynamics of the car. Lowering the ride height lowers the center of gravity, reducing body roll. The between the ground and the floor of the car is known as the rake angle. A steep rake angle, noticeable at this year’s Red Bull F1 car, increases downforce at low speeds. Low rake will increase downforce at medium to high speeds since air can flow smoother under the car. Wings and splitters work just like airplane wings, but then the other way around. Lift downwards gives you downforce, sticking the car to the ground. More downforce at the back will reduce oversteer and vice versa.

Setting up the car

With all parameters in mind, we can start setting up our car. So where do we start?
On the internet, complete setups for certain cars and tracks can be downloaded straight away. However, if you have actually no idea how car setups work, they will be pretty much useless (which will make more sense later on). Besides that, some setups even have to be paid for, and might not even work for you!
When preparing for a race, start off with a baseline setup. This will be your starting point for further adjustments. Baseline setups created by the community can be found on the internet and easily imported into the game. The next step is to perform some practice laps on the track. Run test sessions at the same time of day, under the same weather conditions and same duration as the race. Analyze how the car behaves. Does it oversteer or understeer? And where exactly in the corner does this happen? After this, it is a matter of problem-solving!

Example

You are preparing for a 40-minute race at Monza, a relatively high-speed track, in dry weather. After some testing with the baseline setup, you notice that the car handles well in the fast sweeping corners, but tends to oversteer at the exit of the chicane (a slow set of corners). Suppose that oversteer would occur at the high speed corners, this could be solved by adding more downforce to the car by adjusting the spoiler of the car, but at the cost of increased drag and therefore lower top speeds. In our case, we need to increase (mechanical) grip at low speeds. This can be achieved by softening the springs of the suspension, in order to keep the wheels on the (bumpy) road as much as possible and maintain grip. But again, this would decrease tire life. Compromises…
It becomes quite clear that fiddling around with a car setup is a matter of trial and error. When doing this right, it can save you precious seconds and make the difference between winning and losing. That is why doing research in this rather complicated field is interesting within the simracing division of Esports Team Twente.