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F1 Active Suspension (Explained In Simple Terms)

The technology in F1 cars is astounding, and the sport has been a breeding ground for innovation for many years. There are a number of neat technologies present in modern cars that owe their development to the engineers of the sport, and one important F1 innovation was active suspension.

Active suspension in F1 is a system that actively adjusts the suspension of each wheel to ensure a consistently optimum ride height. This active system can be hydraulic or electronic, and it adjusts according to the conditions on the track in order to maximize the aerodynamic performance of the car.

However, the suspension of a car is a complicated system, and even more so when discussing the suspension of an F1 car! Below, we go into more detail about what active suspension is in F1, and how it works.

What Is Active Suspension In F1?

Active suspension in F1 is an electro-mechanical system that can actively adjust the stiffness and position of the suspension connection to each wheel. This is able to adjust the ride height of the car to ensure an aerodynamically efficient position despite the different conditions around a circuit.

Basics Of Suspension

To start with the basics, the suspension of an F1 car is how the body of the car is attached to the wheels. The tires touch the road, but the body of the car is elevated from the road by the way it is attached to the wheels. Some freedom of movement is required in this attachment, to allow for unevenness in the track surface and going across the kerbs.

Conversely, suspension can also be seen as the mechanism that keeps the tires firmly on the track surface, ensuring that the tires are constantly providing grip. This suspension arrangement should maximize the surface area of the tire in contact with the road when under the highest load, which is when the car is cornering.

In its simplest form, suspension consists of a spring and a damper (the damper in road cars is commonly called the shock absorber). The spring absorbs energy by compressing as the wheel moves relative to the car body, such as when the wheel recoils upwards as it hits a bump. However, if this spring simply released that energy, it would send the wheel bouncing back onto the road and up again.

The damper dissipates that energy by providing a force in the opposite direction and releasing the energy slowly. This damper is usually a hydraulic cylinder containing a piston, with a limited rate at which the hydraulic fluid can move from one side of the piston to the other, therefore limiting the speed at which it is able to move, making the suspension stiffer.

Elements Of Active Suspension

Active suspension adds some intelligent electronic elements, namely multiple sensors, adjustable dampers, a servo motor for each wheel, and a computer called an electronic control unit (ECU). The sensors detect changes in the movement of the car and each of the wheels, send these signals to the ECU, and in response use the servo motors to adjust the stiffness and position of the suspension.

In this way, the suspension can react to the pressure over each tire by adjusting the stiffness of the suspension to maintain the desired grip levels for each tire. In addition, it can raise or lower the front or rear axle.

Attitude Of The Car

Considering a standard suspension, as a car brakes before a corner, it pitches forward as the inertia of the car shifts the weight forward over the front axle and dips the nose. Similarly, as the car accelerates and the weight shifts to the rear axle, it pitches the nose slightly upward in relation to the rear of the car. You’ll see these effects in your own road car too.

As the car goes around a corner at speed, the body of the car has a natural ‘roll’ towards the outside of the corner. This is due to the inertia of the car and the centrifugal forces placing more pressure onto the tires on the outside of the corner, depressing that suspension further than the suspension over the inside tires.

Also, as the car is going through the corner, the car is moving in a direction that isn’t exactly the same as the direction that the front of the car is pointing in. This slight difference is called yaw. Together, pitch, roll and yaw are referred to as the attitude of a car – its approach to the air (and road) in front of it.

The attitude of a car has a major impact on the effectiveness of the aerodynamics, as it changes the way the air flows over the car as it drives forward through it.

For F1, this means that active suspension can control the ride height of the front and rear of the car throughout the lap, as well as the attitude of the car into corners and adjust for roll through the corners. Therefore, active suspension allows the car to be maintained in the most aerodynamically efficient position at all times.

How Does Active Suspension Work In F1?

One of the key reasons for developing active suspension in F1 was due to ground effect aerodynamics.

What Is Ground Effect?

Ground effect was discovered and exploited in F1 by Colin Chapman at Lotus. He found that designing the car to accelerate air underneath the car using a Venturi section would create a low-pressure zone and suck the car down to the ground. The entire body of the car effectively operated like an upside-down airplane wing, using the airflow to force the car downwards.

However, in order to maximize this effect, it was important to seal the airflow underneath the car relative to the air going around the sides of the car. The gap between the floor of the car and the track surface was also critical to getting the most out of this airflow.

History Of Active Suspension in F1

Active suspension was actually developed separately by two different teams. Lotus, the pioneer of ground effect downforce, was the first team in F1 to try an early active system on the track in 1983. The team’s focus was on controlling ride height in order to optimize and control the downforce generated by ground effect.

However, their active suspension was not run regularly and was last used in 1987. By that time, Williams was developing their own active suspension system. Theirs was less focused on constant ride height, but rather on overall aerodynamic efficiency. They experimented with a reactive hydraulic suspension system in the late 1980s, before trying a new fully active system in the early 1990s.

The system was the best it would get in 1993 on the Williams FW15C, with each wheel independently controlled electronically. In this way, the active suspension could accommodate for and counteract the roll through corners, or the pitch during braking and accelerating.

In fact, the car could be ‘trained’ according to each circuit. It could be programmed before a race to anticipate the adjustments that would be needed for the next corner along the track. This made the car incredibly stable – and greater stability leads to faster lap times.

Active Suspension vs Passive Suspension

The current suspension arrangement in F1 is a fully passive system. It consists of rockers, torsion bars and dampers. The rocker converts the vertical motion of the wheel into a rotational, angular movement.

The ‘spring’ to absorb this energy is actually a torsion bar – a metallic bar held stationary at one end that twists with the rotational movement of the rocker. The torsion bar stores this rotational energy and releases it again as it returns the rocker to its zero position.

A damper is connected to the rocker to slow this movement and dissipate the associated energy. The damper is a hydropneumatic cylinder, which is a cylinder that contains both compressible air and incompressible liquid.

A further element of the current passive suspension is the anti-roll bar. This connects the two wheels on either side of an axle, to limit how much each wheel can move relative to the other. In other words, if the left-hand front tire is to move upwards slightly, the anti-roll bar will move the right-hand front upwards too. This counteracts the roll of the car into a corner, hence its name.

Pullrod vs Pushrod

The connection of each wheel to the rocker within the car’s body is by a pullrod or pushrod. The difference between the two is the geometric arrangement of the wheel hub in relation to the suspension arrangement within the body. Pushrods are mounted higher on the body relative to the wheel hub and ‘push’ the rockers. Pullrods are mounted lower and ‘pull’ the rocker.

A common arrangement for F1 cars (since 2009) has pushrod suspension for the front axle and pullrod for the rear, as this geometry generally favors the airflow across the aerodynamic elements of the car.

However, this is only a generalization – for the 2022 season, McLaren and Red Bull both employed pullrod suspension for the front axle, and McLaren even switched to pushrod for the rear. These differences in suspension arrangement were another interesting twist on the variation of the cars under the 2022 regulations.

Passive Suspension Tricks

The benefits of active suspension have been tantalizing ever since its advantage was shown so clearly in 1993, and then subsequently banned. However, F1 teams have found clever ways to utilize passive suspension elements to try to extract some of the benefits of active suspension. This has resulted in some incredibly complex hydraulic arrangements.

FRICS Suspension In F1

An example was the FRICS system in the 2014 season. FRICS stands for Front Rear InterConnected Suspension. In this system, the front axle suspension was connected hydraulically to the rear axle suspension.

In its simplest form, this meant that, as a car was braking and it pitched forward, the additional pressure on the front axle suspension could be translated into additional pressure at the rear axle suspension, pushing the rear of the car lower, and compensating for the pitch.

In the complex arrangements, individual wheels were connected in different ways to the other wheels hydraulically, with the relative reaction of the wheels controlled by flow control valves on the hydraulic fluid connecting them. Effectively mechanical computers, these were almost able to be mechanically preprogrammed according to each circuit.

Again, the major aim of this suspension was to influence the attitude of the car to maximize the aerodynamic efficiency. The system was therefore outlawed at the end of the 2014 season as it was considered a moveable device for the sake of influencing aerodynamics. The regulations now expressly state that the front axle suspension must be completely independent of the rear axle suspension.

Is Active Suspension Allowed In F1?

Active suspension is not allowed in F1. The Formula 1 regulations make significant effort to ensure that only conventional, passive suspension systems are used. Active suspension was banned in F1 for the 1994 season.

Some of the details of those restrictions include that “any powered device which is capable of altering the configuration or affecting the performance of any part of any suspension system is forbidden. No adjustment may be made to any suspension system while the car is in motion.”

Allowing active suspension back into F1 would allow highly optimized (‘peakier’) aerodynamics, which would have a larger fall-off of pace when in non-ideal conditions. This would go against the spirit of the 2022 regulations, which require the cars’ aerodynamics to be as unaffected as possible so that the cars can follow closely with only a minimal drop in performance.      

Why Did F1 Ban Active Suspension?

F1 banned active suspension in 1994 because the cars were deemed to rely too heavily on driver aids. Active suspension was also banned because of increasing costs in developing the technology, and there was a safety aspect too, as cars could become unpredictable under the wrong conditions.

Active suspension was outlawed in the F1 regulations after the 1993 season. The reasoning has a lot to do with the context of the sport at the time. It is widely acknowledged that the cars of the 1993 season were the most technologically advanced F1 cars. To be more accurate, they were the cars that had the most electronic technologies for their time included across the functioning of the car.

The Williams FW15C was a prime example of the peak of electronic driver aids in 1993. It was equipped with traction control, a semi-automatic gearbox, active suspension, and anti-lock brakes (ABS).

There was even a “push-to-pass” button, which used the active suspension to raise the rear of the car to reduce the drag of the diffuser, allowing a higher top speed on the straights. This, coupled with a temporary boost to the maximum engine revolutions by 300 RPM, and made overtakes much easier. It’s clear to see how all the smart electronic controls in the car made it much easier to drive.

In the context of that era of the sport, it was time then to get rid of the computers that made a driver’s job relatively easy – the computers that superhumanly handled all the tricky bits. By excluding the use of many of these digital technologies, the control and the responsibility was put firmly back in the hands of the drivers.

It also aimed to save some cost. The FW14B was already dominant in 1992, but the gap to the rest of the field only grew in 1993 with the refinements made in the FW15C. It would have been a necessity for other teams to develop their own complex electronic systems in order to be able to compete. The ban aimed to avoid the vast sums of money that this development race would have cost each team.

Safety Reasons

Further than that though, the active suspension particularly allowed the attitude of the car to always be kept inside a small optimum window. This meant that the aerodynamics were designed to be much ‘peakier’ – providing maximum aerodynamic efficiency within a small window of conditions and disregard the need to have reasonable levels of downforce in other non-ideal scenarios.

The high downforce levels allowed higher cornering speeds. This introduced a safety risk, that if for any reason the car was not kept within that narrow window that kept the car working at peak performance, the downforce would fall away, and the car would behave unpredictably or simply leave the track.

Would Active Suspension Fix Porpoising In F1?

Active suspension has risen again as a popular topic since the ground effect was reintroduced in the 2022 technical regulations. The ground effect aerodynamics introduced a detrimental effect called porpoising, and active suspension seems to many to be the easiest solution to the problem.

What Is Porpoising?

Porpoising is the rapid bouncing up and down of the rear of an F1 car, particularly on the straights. It is an unwanted consequence of the return of ground effect aerodynamics in the 2022 F1 cars. The floor of the car creates significant downforce towards the rear axle, as it’s designed to do.

However, as the car drives down the straight, the levels of downforce generated pull the rear of the car closer to the track. When the gap between the floor and the track is too small, the airflow under the car stalls. The stalling air results in a sudden loss of downforce, and the car springs back up. This reestablishes the air flow along the floor, generating the downforce once again.

This causes the rear of the car to oscillate rapidly. These oscillations are referred to as porpoising as it is reminiscent of a porpoise swimming, going up and down in the water. Porpoising creates some genuine reliability issues for the cars, due to the vibrations of the body and the bumping of the rear of the car on the track. It also makes the cars incredibly uncomfortable for the drivers.

One of the reasons that the 2022 cars struggle with porpoising on the track is that it is a very difficult effect to replicate in a wind tunnel or a simulation.

Would Active Suspension Fix Porpoising?

Active suspension would fix porpoising, as it would allow the car to maintain a fixed height above the surface of the track even under increased downforce. This constant ride height would prevent the floor from being sucked to the ground, ensuring that the airflow under the car would not stall.

However, active suspension would bring some negatives with it as well. It would add weight to the cars, which are already the heaviest they have ever been in the history of the sport. The weight of the cars has been on an upward trend since 2009.

The Cost Of Active Suspension

Further, it would increase costs. If active suspension was allowed again in 2022, each team would need to develop their own bespoke system. It is anticipated that at least a year, if not two, would be required to get a race-ready system into the cars. The development race would invariably add costs, which goes against the philosophy of the recently introduced cost cap.

It has been suggested that a standardized ‘spec’ system be provided, that all teams would be mandated to use. However, given the many differences in the aerodynamics of each car, let alone McLaren and Red Bull using pullrod rather than pushrod suspension for their front axles, there would be meaningful knock-on effects of incorporating a spec system.

In the time it would take to incorporate active suspension (either bespoke or spec), each team’s engineers would likely have brought the porpoising problem under control within the existing regulations, with less cost and no additional weight.

What Else Could Fix Porpoising?

Active suspension is not the only answer to fixing the porpoising issue. F1 teams still have a number of routes that they can take to reduce the problem. Unfortunately, the simplest of these result in a tradeoff of significant downforce loss, which is why teams are treading carefully.

A simple method of combating porpoising is to run the car with some rake – that is, the back of the car higher than the front. When the large downforce generated by the floor acts towards the rear axle, the larger ride height there prevents the bottom of the car from getting too close to the road. However, there is some performance loss with this adjustment.

There are some clever tricks that can be incorporated into the design of the floors to help. One can be the creation of vortices on the outer edges of the floor that ‘seal’ the airflow under the floor, reducing the downforce lost by increasing the ride height. Another tweak is to include slots or cutouts in strategic areas of the floor that prevent the air flow under the car from stalling.

Stiffening the floor by attaching it at additional points with stay bars can also reduce porpoising. The additional stay bars reduce the deflection of the floor towards the road when experiencing peak downforce.

Does F1 Use Active Aero?

F1 does not allow the use of active aero. The use of movable or flexible bodywork is specifically excluded in F1 under the current set of regulations. However, technically F1 does have active aero – in the DRS flap that drivers use on the straights to pass other cars more easily.

Whereas active suspension concerns only the suspension system of the car, active aerodynamics affects how the car manipulates airflow over and under itself. F1 has specifically aimed to prevent the use of moveable aerodynamic devices. However, there have been some controversies related to skirting around the letter of the law with respect to moveable aero devices – this is F1 after all!

In the 2010 season, all the talk was about the F-duct. This was a device used by McLaren to direct air to the rear wing to stall it (essentially make it stop producing downforce), significantly reducing drag and therefore increasing top speed.

The key was that this was activated by the driver covering a duct with their knee or hand, thereby staying ‘legal’ as driver movement was not regulated – yet. For 2011, any system “which uses driver movement as a means of altering the aerodynamic characteristics of the car” was prohibited.

Flexi-Wings

Flexible wings that deflect under load is another area where teams have tried a number of times to gain an aerodynamic advantage. Most recently in 2021, there was some furor over Red Bull’s rear wing apparently rotating to reduce drag under extreme loads on the straights.

Similarly, there were accusations that Mercedes’ rear wing flap was flexing under load. This led to an infamous incident at the 2021 Sao Paulo Grand Prix, where Max Verstappen was fined €50,000 for touching Lewis Hamilton’s rear wing while the car was in Parc Fermé.

Hamilton’s car would go on to fail scrutineering for having too large a gap between the two elements in the rear wing (although not as a result of Verstappen’s contact). As a result, Hamilton was excluded from the Friday qualifying session, which essentially forced him to start from the back of the grid for Saturday’s sprint qualifying. Despite this, Hamilton would go on to win the race on Sunday.

Will F1 Use Active Aero In The Future?

Active aero (other than DRS) has been prohibited for so much of F1’s history that one would never expect a time that it would be legal. However, F1 has said that it is planning to allow some active aero in future regulation changes. The main focus of the update to the regulations then will be reducing the carbon footprint of the sport, towards F1’s commitment to be carbon neutral by 2030.

Active aero is planned for the future to allow a reduction in the drag of the cars while still having the similar cornering downforce. This is intended to save up to a third of the fuel used during a race. However, F1 have not yet given any further details of what scope of active aero they are planning to allow.

Final Thoughts

Active suspension in Formula 1 is a suspension system that automatically adjusts the suspension at each wheel to keep the car’s ride height and attitude consistent. This system relies on computers to control the suspension depending on the track conditions, to optimize the car’s performance.