Kenny Sebastian
How do F1 cars brake so hard?
There are many aspects of the braking system of F1 cars that make it so different from normal cars. One of the most striking factors is the force necessary for the brakes to react.
So why are the F1 brakes so hard?
The F1 brakes are hard because regulations require that all braking force be generated by the driver alone, so there can be no electrical assistance. It is also rarely necessary to brake smoothly, so the pedal is almost like an on/off switch.
Below we will look at more details about what these regulations mean and why they are important, and we will also discuss why even with a hard brake pedal, drivers can benefit from better brake control.
Ask any junior formula driver who tries an F1 car for the first time what is most impressive, and most of the time they will say that the brakes are. Given the performance of nearly 1000hp and +4g turns of the F1 car, it is the braking performance of +5g that attracts all the attention. Achieving this incredible feat, stopping the 200-mph car in a second, is a complex mix of aerodynamics, mechanics, and electronics.
Performance
A current brake system in the F1 car includes brake discs, calipers, pedal, and master cylinder, all connected by hoses and a wire-to-wire brake that controls the rear brakes. Despite the deceleration available, the brakes are heavily regulated to limit their ability to deliver even higher performance.
By slowing the car by 210 mph approaching the 13th lap of the Circuit Gilles Villeneuve de Montréal, the driver will brake for just 2.09 seconds, slowing to 83 mph in just 122 meters, or about 20 lengths! To achieve this incredible feat, you need more than brakes, you need wide Pirelli tires for traction, plus huge amounts of aerodynamic force and powerful leg muscles. It is only possible to achieve this 5G performance because the car has a lot of grip on the tire contact patch.
To take full advantage of the available braking potential, most of the effort is required at the beginning of braking, when the aerodynamic force is highest. The driver’s braking effort is not entirely on/off, as you will need to relieve the pedal as the aerodynamic load decreases with speed, in order to balance the delay with the available grip. This combination of aerodynamic load, tyres, and the braking system makes F1 cars the most efficient deceleration machines in motorsport.
The rules around brakes in an F1 car
There are many strict rules in the world of the F1, and these rules are established by the FIA, the governing body of the sport. The rules are in place to help keep the sport as fair as possible, and generally to keep the cost as low as possible. There are rules concerning each part of the car, and one of the most regulated is the braking system.
Without Electrical Assistance
Brake rules have not changed much over the years. However, the main thing to consider for this article is the rule that prevents motor assistance for the brake pedal. First of all, let’s look at what electric assistance means in terms of your normal road car, and how you use it every day maybe without even realizing it.
Almost all cars are now forced to have what is called assisted braking. These systems can work in different ways, and first, we will consider one of the most common, which uses a vacuum system. This system uses a vacuum created by the engine or an external pump to effectively provide an additional force on the brake cylinders when the pedal is pressed.
Vacuum power
This reduces the amount of input required by the driver and boosts the pressure of his pedal to quickly stop the car. The effects of the vacuum system can be felt if the engine is turned off and the brake pedal is pressed. At first you may feel normal, but after one or two beats you can hear the sound of the air that is ejected as the void disappears.
If you try to press the pedal again now, it will be much more difficult. That’s what it feels like to walk on the brake pedal without an electric aid. There are other ways to provide electrical brake assistance, and the first is to use additional hydraulic systems that help boost the pressure of the brake pedal. Some systems use air pressure, while others may benefit from transmission aid for transmission.
Reduced input
Regardless of the system used, it is clear that they offer the advantage of massively reducing the input required by the driver. Similar systems are used in power steering, which makes it much easier for the driver to turn the car smoothly. As with these systems, it allows for much smoother braking, which is very convenient in a road car where parts conservation and energy efficiency are essential.
But with regard to F1 cars, the FIA states that “no braking system can be designed to increase the pressure in the calipers above that obtained by the driver who applies the pressure on the pedal under all conditions”. This means that all the systems described above are prohibited. But is it really important?
Do F1 cars need electrically assisted braking?
Formula 1 cars do not need electrical power-assisted braking. F1 races naturally involve a lot of fast driving, but also many sudden slowdowns.
Races are won on the curves because anyone can keep his foot down on the right. It is in the corners that the reflexes of drivers are tested, and they are required to use their ability to brake at the precise moments necessary to give the maximum speed of entry, passage, and exit of the curves.
Being able to make the corner might well win races. But being able to make a good turn depends on a good braking capability. The driver will attempt to brake as hard as possible as late as possible, in order to maintain the highest possible speed before the curve. Then, as they approach the rotation, they will hit the foot on the ground, braking as hard as possible to slow down the car. Very soon, when they turn, they release the brake until they have to press again.
There’s very little in the middle. In many cases, these are all brakes or none at all. This means that it is less necessary to control the fine braking because although drivers have a lot of skill with the brake pedal, they will rarely apply it gently and can therefore treat it as an on/off switch as we said at the beginning. When drivers approach the rotation, they must push the pedal very hard to get the brakes.
Although it may seem very difficult at first, practice makes it perfect and drivers get used to it very quickly. This additional pressure requirement means that the driver will not accidentally apply the brakes very hard, something you may feel from time to time.
Not always the case
Although we said that this is generally all or nothing about braking, it is not a firm rule. One of the advantages of having a very hard pedal without power is the fact that it actually gives you much finer control when you need it. An easy way to explain this is that it works by measuring the applied pressure instead of the distance the pedal travels over.
Although this is not the case in normal cars, the power aid indicates that the braking force depends on how far you push the pedal inward. Without energy aid, you feel more dependent on how you press the pedal, even if you don’t seem to travel far. This provides more space for fine control when using an F1 brake pedal.
Hard, but not so hard
Just because the brake pedal feels difficult and can be difficult to press the first time you try, it does not mean that drivers constantly struggle to brake the car. As with everything, practice is perfect, and drivers quickly get used to the forces necessary to walk on the brake pedal.
Brake-by-Wire (BBW)
Since 2014, with the modification of energy recovery systems (ERS), the use of a wire braking system (BBW) for rear brakes has been allowed. As the ERS-K recovers power during braking, the MGU drag acts like a brake, which also slows down the car.
However, this effect is not constant, the braking effort of the MGU-K varies depending on its Regen setting and battery charge. With this modification of the ERS braking force, the driver will suffer from unbalanced braking, sometimes getting rear braking from the ERS, sometimes not and not always with any warning.
As a result, the FIA allows a system called BBW to control the rear brakes. There is still a rear master cylinder on the pedal, but the brake line ends in the BBW unit mounted inside the steering gearbox.
This unit recognizes the driver’s braking demand and, depending on the pressure exerted on the rear brake line, will then know the regenerative braking effort that the ERS will apply through a SECU signal. It is then deduced from each other and, through a hydraulically actuated master cylinder, applies only the pressure on the rear brakes necessary to turn off the ERS effect, giving the driver a balanced braking.
That’s the simple explanation! The actual software to give a constant braking effort to the driver is much more complex. In addition, the driver will have a different feel on the pedal, since the rear master cylinder is effectively plugged in, so that some compliance is put into the system with valves and accumulators to reproduce the conventional “feeling” of the pedal.
Being essential for safety, the BBW unit has protection against breakdowns. In the event of a failure of the sensors or the active master cylinder, the brakes are reactivated by pressure in the rear brake line.
In addition, to avoid the use of pseudo-anti-lock braking software, the speed of the wheels cannot be a factor in the system. Now, with the electronic bias of possible brakes, drivers use the steering wheel controls to change the brake bias and migration of the brake bias, without the need to remove a hand from the steering wheel to adjust them.
Therefore, the next time you see a driver braking in a 200 mph corner near a dead end, it is worth contemplating how much happens when the driver seals on the pedal.
Last thoughts
There are many parts of an F1 car that are highly regulated, which makes them very different from their road car equivalents. One of these parts is the brake pedal, which due to the rules of the FIA has no electrical aid. This means that the pedal is very difficult to push, and it requires a lot of force to stop the car.
But just because it’s hard to press, it doesn’t mean it’s hard to use for F1 drivers. Instead, it allows them to have very fine control over their braking, and due to the driving styles required in Formula 1 races, they usually don’t use brakes at all, nor at all at all.
This video will explain it in more details.