One of the most debated elements of the 2021 Formula 1 season was rake angle. There were many different car philosophies and approaches that were taken by teams towards this concept, and it made a huge difference to their cars. Rake angle is an important concept in F1.
Rake in F1 refers to the difference in ride height at the rear of the car compared to the front. A positive rake angle is when the rear of the car is raised higher than the front. This allows the car to produce more downforce at the expense of extra drag and slower straight-line speed.
Rake angle used to be very important, but with the 2022 aerodynamic regulations, it became less varied among the teams. The return of ground effect made shallower rake angles and lower ride height even more important than before. Below, we’ll discuss rake angle and its effect on F1 cars.
What Is Rake On An F1 Car?
Rake on an F1 car refers to the angle at which the rear of the car is raised compared to the front of the car. All F1 cars have some rake, as if they didn’t, the car would act like a plane’s wing. This means they wouldn’t produce much downforce and would instead generate lift.
In 2021, Red Bull, among other teams, ran with a relatively high rake (i.e. the back of the car raised significantly vs the front). A shallower rake angle was used by Mercedes because the team had a different philosophy. However, both the Red Bull and Mercedes cars were incredibly fast throughout the 2021 season. It all depends on how the car is designed and how the aerodynamics of the car work.
An aggressive, or high, rake angle is when the rear of the car is much higher off the ground than the front of the car. This gives the car a distinctive look, especially when viewed from the side. The car looks to be pushing its nose further into the ground, and there’s a clear gap between the rear of the car and the ground.
A shallower or lower rake angle looks more “normal” when viewed from the side. In this case, the car will have almost equal height above the ground from the front to the back, although there will still be some rake. The car might also seem to sit closer to the ground. The choice of rake angle affects cars differently.
A Note On Rake
It should be noted that rake refers only to the underside of the car, and not the overall height of the car itself. In other words, if a car has high rake, the rear of the car looks to be sitting higher off the ground, but this doesn’t mean the rear wing is sitting higher than on a low rake car, for example. If this was the case, there would be more drag.
So, teams that ran high rake cars would also reduce the overall height of the car to compensate for this. This could be achieved by lowering the overall height of the car towards the rear. It could also be compensated for by running skinnier or ‘flatter’ rear wings, but how each team approached the issue varied depending on the designs of their cars and on the individual tracks too.
How Does Rake Affect Aerodynamics?
A higher rake angle affects aerodynamics by allowing more air underneath the car at the rear and into the diffuser. The diffuser then has more air moving through it, which creates a larger area of negative air pressure underneath the car that effectively sucks the car to the ground.
Rake angle has a huge impact on aerodynamics, and this is why there was such a big difference between the Red Bull and the Mercedes in 2021. The Red Bull was extreme in its rake angle, and it benefited in different areas when compared to the Mercedes. It should be noted that this rake angle was typically only around 1-2 degrees.
High Rake Cars
The higher the rake angle of an F1 car, the more underbody downforce it could generate in the past. Now that the ground effect has returned to F1, this is not strictly true, and we’ll talk more about this in a later section. But considering F1 cars of the past without the ground effect, having a higher rake allowed more airflow under the car, maximizing the power of the diffuser.
The diffuser on an F1 car is a component at the rear that generates downforce. By allowing more airflow through it, the car can generate more downforce. It does this as, when there is a bigger difference between the ride height at the front and the back of the car, there is also a bigger difference in air pressure. This leads to more downforce.
However, this higher rake has other consequences. Aside from raising the center of gravity of the car, affecting things like roll and overall handling of the car, it also increases drag. Because the car is producing more downforce at high speed, the maximum straight-line speed is reduced.
Low Rake Cars
A lower rake angle, on the other hand, allows for less drag as the entirety of the car from front to back sits lower to the ground. As a consequence, there is a smaller difference in ride height between the front and the rear of the car, making for a smaller pressure difference, and therefore less under body downforce.
So, while a low rake car would usually have better straight-line speed, it would produce less downforce via the floor. Teams usually compensated for this by using a longer wheelbase. This would increase the total volume of airflow under the car, mitigating the loss of downforce that resulted from running a lower rake.
High Rake vs Low Rake In F1
There has been much debate over which is the better car philosophy to go with. Teams can’t really adapt their cars throughout the season to use a different rake angle, because the cars would have been developed from the ground up with either high or low rake in mind.
Ultimately, it was a close call between the high and low rake philosophies in the 2021 Formula 1 season. Red Bull took the Drivers’ Championship and Mercedes took the Constructors’ Championship. However, their individual results throughout the season were varied.
There were some tracks where the low-rake Mercedes was able to gain a lot on the straights with their setup. This helped them on circuits with long straights, and it also helped them to overtake during the race. However, we really saw them suffer on circuits where downforce was important, such as Monaco.
The Red Bull ran a high rake angle and they succeeded on tracks that had a lot of slow to medium- speed corners. This was because there was more air flowing into the diffuser, allowing the car to produce more under body downforce. Overall, it’s difficult to say which was better, but it makes a big difference in how the car handles. But things changed in 2022.
Why Is Rake Angle Less Important In 2022?
The rake angle is less important now because the 2022 aerodynamic rule changes reintroduced the ground effect. With this concept being revived, the high-rake cars have also somewhat disappeared. Formula 1 cars are now designed with Venturi tunnels underneath, which require the cars to run relatively low to the ground for them to be effective.
The Venturi tunnels will only work if the floor of the car is “sealed,” which means that the outer edges of the floor are as close to the ground as possible, to prevent high pressure air from rushing into the space under the car, eliminating the ground effect. If the car’s ride height is too high, the car won’t produce enough downforce.
Because the cars are now designed to produce a large portion of their downforce via the floor, high rake cars are not only less effective, but also not required. In the past, F1 teams were trying to generate as much downforce via the floor of the cars as they legally could, as regulations made it quite tough, and any marginal gains were key.
This meant that finding the balance between high and low rake was critical to the performance of the cars. However, when the regulations changed to force teams to instead maximize the downforce generated with the floor of the car, teams now had no reason to run with higher rake, as they would only suffer, and their competitors would all be now trying to run as little rake as they could.
Some Rake Is Still Required
An F1 car does need some degree of rake though. Because of the shapes of F1 cars, they’re basically designed to work in the opposite way that a plane wing works. While a plane wants to generate lift to take off and stay in the air, an F1 car wants to generate negative lift – or downforce – in order to stay planted to the ground.
With the front and rear wings, among other parts, an F1 car can generate a lot of over body downforce. If the rake of the car was neutral, the car would produce less downforce overall, so that’s just not really an option. But if the front of the car was higher than the rear of the car, not only would the floor be less effective at generating downforce, but the car might take off at high speeds!
What Is The Ride Height Of An F1 Car?
The ride height of a Formula 1 car typically ranges between 30 mm at the front and 80 mm at the rear. Teams will adjust their ride height depending on the circuit they are on, and there are several factors that they need to consider when deciding on the ride height of their car.
Formula 1 cars are extremely low to the ground, that much is obvious. However, there is very little space between the floor of a Formula 1 car and the ground, and this is mainly because of the aerodynamic benefits that the cars gain from being so low to the ground.
Less vs More Drag
When an F1 car runs with a lower ride height in the current ground effect era, they generate a lot of downforce. With a higher ride height, they generate less downforce. This means that, in order to be fast over the course of a lap, teams run low ride heights to produce lots of downforce that allows them to be faster in the corners.
However, if a car runs very low to the ground, the ground effect is very powerful. This means the top speed of the car suffers on the straights, just like if they were to run a bigger rear wing for example.
As they go faster and faster, the ground effect sucks the car lower to the ground with a bit of extra drag at the rear (as a result of the diffuser having a stronger effect), and while the extra drag is far less than would result from a larger rear wing, it is still measurable. So, for maximum speed, a higher ride height would be the approach, right? It’s really not that simple.
High vs Low Ride Height
Teams will change the ride height of their car depending on the circuit they are driving on. If a circuit is extremely bumpy for example, they would most likely increase the ride height in order to prevent the floor from being damaged when the car goes over those bumps. However, the power vs downforce comparison is far more important to consider when optimizing the car’s ride height.
On a high-speed ‘power’ circuit such as Monza, the teams would traditionally run higher ride heights than any other circuit because they need to maximize their top speed. Downforce is less important on these circuits, and teams can sacrifice their downforce generated by the ground effect for higher top speed to find more lap time on the straights.
However, on circuits such as Monaco where the cars need to have high downforce setups, the teams will run their cars as close to the ground as possible. The challenge with Monaco in particular is that it’s a very bumpy circuit, so the teams also need to consider this when tweaking their ride height. For other high-downforce tracks that aren’t as bumpy, low ride heights are best.
Why Is Ride Height So Important In 2022?
Ride height is so important in 2022 because the aerodynamic regulations brought the ground effect back, and instead of just using airflow over the top of the car to produce downforce, the cars can now use the floor and the Venturi tunnels to produce downforce.
With the ground effect, teams need to try and seal in the airflow underneath the car. In order to create this seal, the car needs to run as low to the ground as possible. If the ride height is too high, the higher-pressure air at either side of the car would simply rush into the floor, effectively preventing the car from generating downforce through the underside of the car.
So, it’s therefore still about finding a balance. Even though rake is less important in 2022, the ride heights of the cars are still tweaked on a per-track basis to ensure there is the optimal setup for each car. But ride height doesn’t just affect aerodynamics.
How Does Ride Height Affect Handling?
Ride height not only affects the downforce and the top speed of the car, but also the handling of the car. Naturally, lowering the ride height of the car also reduces its center of gravity, and it will affect weight transfer too. This affects how an F1 car handles into and through the corners.
Lowering the ride height over one axle increases the load on that axle. With lower ride height at the front than at the rear, weight transfer to the front of the car increases. This means that the front tires will tend to have more grip, making the car less likely to understeer. It also increases braking power at the front wheels, and boosts traction during cornering.
Having a lower ride height at the rear (compared to a high ride height – we don’t mean low ride height at the back and high at the front, as that would generate lift as previously discussed) increases the weight over the rear axle. While this would provide better grip under acceleration (F1 cars are RWD), the car would suffer in the corners with decreased traction under braking and when cornering.
Why Are F1 Teams Struggling With Ride Height In 2022?
Some F1 teams are struggling with ride height because the 2022 regulations reintroduced the ground effect, which means ride height is key for producing downforce. But with the ground effect and reduced ride height comes the effect known as porpoising, which affects performance.
Porpoising in F1 is the bouncing effect seen as a result of the car generating so much downforce via the floor that the car gets sucked very close to the ground. When the car gets too close to the ground, the airflow under the car stalls, taking away the downforce, and the car springs back up, only to then be sucked back down as downforce increases again. This cycle then repeats.
Changing The Ride Height
The easy solution to porpoising is to increase the ride height to allow the air to always be able to flow under the car, rather than being effectively cut off and stalling underneath as the gap reduces too much. However, increasing the ride height will also cause the car to lose downforce through the corners since the floor is not able to seal properly and produce downforce, increasing lap times.
Teams are now faced with the dilemma of finding the ideal ride height where they have minimal porpoising and the highest amount of downforce they possibly can have at the same time to allow for high cornering speeds. Outside of solutions like active suspension, teams will simply have to work until they find the ride height balance that works for them.
Rake angle refers to the difference in ride height between the front and rear of the car. A high rake angle would traditionally allow for more downforce to be generated under the car. However, the 2022 regulation changes meant that lower rake designs were far more favorable.