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For anyone like me who has been fascinated by technology and motorsport since their youth, they couldn’t help but tinker with engines from the early days. In my case, it was a Vespa that I used to tune a bit in my garage at home. When my dad cottoned on, he just told me not to forget the brakes. It wasn’t much later that I understood he wasn’t just talking about safety…
Brake and you lose. This somewhat plebby saying is certainly justified, but it should actually read: Brake right to win! Anyone can accelerate in the straights. But, in motorsport, being able to brake perfectly – taking all braking factors into account, such as tyres, fuel level, temperature, etc. – is a skill that distinguishes good drivers from real champions.
Nowhere else can you take so much time off your competitors than by driving a series of corners perfectly. As well as having the right touch and power in the foot, it goes without saying that a first-class braking system is required. At the upcoming French Grand Prix in Le Castellet this weekend, braking is once again the top priority – in complete contrast with the high-speed racing seen at the last round in Canada. This is more than reason enough to look more closely at the braking system used on a Formula 1 car.
Braking in Formula 1 is handcrafted
While you can rely on convenient assistance systems such as servo support and ABS in your Mercedes-Benz, braking out on a race track is still an example of true handicraft. The Formula 1 regulations state that braking force may only be applied by the driver. They need very strong legs to do so. However, they are also supported a little by the force of the braking manoeuvre since the car decelerates at about 5g (in comparison, when emergency braking in a road vehicle, we reach 1g).
The weight of the leg on the brake pedal adds its own kind of servo support and pushes around 100 kg into the pedal. Meanwhile, the driver must embrace the delicate touch of a concert pianist to steer the car through the corners at the tyres’ absolute limit – a fascinating contrast between control and caution.
All hands on deck at the Formula 1 in France
Finding the perfect moment to step on the brakes changes constantly throughout the race since fuel is being burnt and the tyres are getting worn – drivers must remember this. The trickiest moment of the weekend is, without doubt, braking at the first corner after the start: Neither the brakes or tyres have reached the optimum temperature at the start of the race. It is therefore difficult to estimate how much braking potential they will offer. And then there’s the battle for position.
Drivers must react to many different elements in milliseconds: Make sure they get the right slipstream, predict what their opponents will do next, estimate the level of grip, ensure that they don’t brake too early and thus loose position. All while not missing any opportunity to gain a position themselves. Wow!
Complex brake balance of F1 cars
Balance is also required for power distribution between the front and rear axles. It depends on the car’s weight and aero-balance at every corner. The introduction of hybrid power units has made brake balance somewhat more complex but far more sophisticated as a result.
While braking on the front axle is fairly similar to a road vehicle, it’s more complicated on the rear axle: Here, brake power is used in combination with the energy recovery of the hybrid electric engine The electronic control unit spontaneously calculates the brake balance so that it can be changed at different moments throughout the corner – such as when the speed drops or the driver steers.
When braking in a road vehicle, we’re generally driving in a straight line. What’s more, we rarely reach the limit so much as to trigger the anti-lock braking system. Racing drivers drive completely differently. Every time they step on the brake, they want to reduce their speed as quickly as possible. This means they are pushing the brakes to the point where they lock the tyres – at every corner of every lap.
Furthermore, they don’t only touch the brakes when the car is driving in a straight line. They touch them at the end of the straights while steering and only release the brake once they have hit the corner’s apex – so just a moment before they accelerate again on the exit of the corner. Throughout this time, the brakes are almost as important as the steering wheel for controlling the direction in which the vehicle is travelling.
Steering with the brakes
If everything is going well for the driver, the car is at the limit on all four tyres during this manoeuvre before it starts to slide, yet without deviating from the racing line that the driver wants to follow through the corner. If things are not going quite so well, the car starts to push a bit more over the front tyres rather than the rear. This means the driver experiences understeer and the car doesn’t turn in. If things are going even worse, the rear tyres slide more than the front. If this is too much the case, the car will spin.
For this reason, it is extremely important for the driver to know how much the front tyres are braking compared with the rear tyres. If the car is unstable and wants to spin on entry into the corner, you possibly have to ask less of the rear brakes and shift more towards the front axle. And if the car is understeering, you may want to do the exact opposite.
Correct over- and understeering using brake systems
While cornering, the driver wants different things at the same time – from initial braking to steering and the apex. When the driver starts to steer, the vehicle can often show a natural tendency to oversteer which is then replaced with ever more understeer up to the apex. This tendency can be partly compensated using a sophisticated braking system that demands less of the rear brakes when steering (to stabilise the vehicle) and then asks more of them as the vehicle travels towards the apex (compared with the front brakes).
This clever process is called brake migration – dynamically shifting the brake balance as a function of brake pressure. This smart trick is made possible by the “brake by wire” system. Depending on the rotary dial settings on the steering wheel, the BBW system manages the input of the three main braking aspects (brake callipers, engine braking and MGU-K) to provide the driver with a rounded and predictable braking performance at the rear, meaning he can push the vehicle to its limit of liability without an anti-lock braking system.
Granted, my father certainly hadn’t thought of that when he advised me to have better brakes if I wanted to pimp my Vespa. He wanted for me to be safe while out on the road. And that’s what we want for Lewis and Valtteri this weekend in France – let’s hope for another 1-2. Brake well, lads!