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What makes a brake? F1 brakes explained

F1 Williams Martini Racing FW41

By: Acronis Motorsport | Published: 2018-04-17

Formula 1’s very essence is speed. Forward motion, the perpetual pursuit of better. Faster, always faster.

But throughout the sport’s 68-year history, every gain in ‘go’ has had to be matched by gains in ‘slow’. For without the ability to control all that urgent velocity, Formula 1 would be nothing.

Braking and deceleration, in fact, are the essential foil and counterpoint to power and acceleration. For while top speed and maximum power figures will always generate the easy headlines, those relating to getting everything back under control are every bit as impressive.

At the Marina Bay Street Circuit, for example – venue for the Singapore Grand Prix – an F1 car will produce braking forces of -4.98G into Turn 7 – the highest braking ‘moment’ of the F1 season. So for a 68kg driver such as McLaren ace Fernando Alonso, that feels like being hurtled forward into his seatbelts with a sudden, almost violent, force of 340kg pushing into his back. That will happen 61 times over the course of the race, into just this one corner.

By way of comparison the braking forces generated by even the most extreme road-going supercar, such as a Bugatti Veyron, peak at only -1.3G. The Space Shuttle on re-entry to Earth’s atmosphere slows at a maximum of only -3G.

Another 5G F1 monster stop occurs on the approach to the final chicane at the Circuit Gilles Villeneuve in Montréal, Canada. Here, cars brake from around 215mph to 85mph in just 1.65 seconds over 97 meters.

And at F1’s next venue, the Azerbaijan GP in Baku – a tight street circuit with high-speed straights followed by 90-degree turns and hairpins – cars will stop twice at

-4.6G, into Turns 1 and 3, then at -4.5G into Turn 7. On each occasion, drivers will have to push the brake pedal with more than 150kg of force.

No other racing series comes close to this kind of eyeball-popping slowing power, nor makes such physical demands of its drivers.

So stunningly effective are F1 brakes, aided by the strong deceleration forces exerted by drag-inducing wings and bodywork, that the sport’s technical regulations have been framed to prohibit further advances in performance. That’s because precise control of braking remains a key differentiator in driver skill. One secret of Lewis Hamilton’s speed, for example, is the exceptional subtlety of his braking technique, so regulators are keen for it to remain an area where driver ability can continue to make a difference.

Modern-day F1 braking capacity is a world away from what existed in past decades, before the advent of carbon-fiber discs and lightweight six-piston calipers: a current driver experiences more braking effect simply from lifting off the throttle at high speed than his 1950s counterpart would have felt from exerting full pressure on the middle pedal.

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F1 brake infographic – the brake disk. Source: © Brembo

A large part of this braking miracle can be explained by the materials science that goes into the composition of individual components in the braking system, such as the brake discs. While their precise composition and design remain closely guarded secrets, many fascinating facts are in the public domain.

For example, a typical F1 brake disc weighs just 1 kg (or slightly more for certain heavy-braking circuits), compared to the 15kg heft of a cast-iron disc fitted to a high-performance road car. The F1 disc will operate best between 350 and 1,000 degrees Celsius, meaning they’re totally unsuited to low-speed, low-temperature use, but rely on more than 1,200 holes to ventilate the disc and promote cooling. A road disc, by contrast, would be usable from sub-zero temperatures to around 500 degrees Celsius.

Of course, Formula 1 braking components are designed only with performance in mind: their maximum life would be no more than 600 miles (and no F1 team would use a disc for more than one race), whereas a road disc would endure 50,000 miles or more.

Brake pads are similarly carbon-reliant. The friction material from which they’re constructed, known as ‘CER’, has been developed to withstand the extremes of racing abuse, such as 1,000 degrees Celsius peak temperatures, so long as the pads are continually cooled by carefully ducted airflow while the car is in motion. This explains why brakes are sometimes seen catching fire when an F1 car is stationary for too long during a problematic pit stop. It’s likely that heat-soak will have raised temperatures beyond 1,200 degrees!

Little surprise, then, that after just 550 miles of racing use, F1 brake pads are spent and that over the course of a season a team will work through nearly 500 sets.

All that forward motion takes an awful lot of stopping.

 

Photo: Williams FW41 at Bahrain International Circuit, Sakhir, Bahrain. © Glenn Dunbar/Williams.