Brembo engineers offer a guide to braking for this weekend’s Formula 1 Rolex Belgium Grand Prix to run at Spa-Francorchamps, Aug. 27-29..
After a four-week pause, the Formula 1 World Championship resumes at the Circuit de Spa-Francorchamps. According to Brembo technicians, this track is one of the most demanding for the brakes. On a scale of one to five, it earned a four on the difficulty index, the same as the Monza track, which will be the racing venue in two weeks’ time.
People rate it as the most complete track in the Formula 1 World Championship because its 7 kilometers (4.35 miles) include every type of curve and straight. One of its distinctive features is the three braking sections of at least 2.5 seconds, something not shared by any other track on the calendar.
Brembo carbon doesn’t melt at 3,000°C (5,430°F)
Carbon discs were first used in Formula 1 in the 1980s, before spreading to other motorsport competitions. Indeed, no other element offers that special combination of light weight, high thermal conductivity and absence of dilation, even at 1,000°C (1,832°F), that distinguishes Brembo’s F1 discs.
The density of carbon is 1.7 grams (0.06 oz) per cubic centimeter, compared with 7.8 grams (0.28 oz) for steel and 7.3 grams (0.25 oz) for gray cast iron. Its coefficient of thermal expansion is one-fifteenth of steel and one-eleventh of cast iron. The melting point of carbon is higher than 3,000°C (5,430°F), compared with the 1,200°C (2,190°F) of cast iron and 1,800°C (3,270°F) of steel.
On the road, 3 meters (3.3 yards) make all the difference
Carbon discs aren’t suitable for road use, mainly because the braking system doesn’t reach the minimum operating temperatures needed, but also due to their high consumption. Some of their benefits, however, can be found in the carbon ceramic discs of which Brembo, via Brembo SGL Carbon Ceramic Brakes – a joint venture with SGL Group – is the main worldwide manufacturer.
Carbon ceramic discs allow a saving of 5-6 kg (11-13 lbs.) in weight compared to traditional cast iron discs. What’s more, their lifespan may even match that of the vehicle they’re mounted on. It depends on how it’s driven. But, above all, carbon ceramic guarantees a reduction of about 3 meters (3.3 yards) in the braking distance from 100 km/h to 0 km/h (62 mph – 0 mph) compared with a traditional disc.
One braking section per kilometer
Despite being the longest track in the World Championship, the brakes are used just seven times per lap, an average of once per kilometer. On the other hand, in the Monaco GP, the brakes are applied on average every 300 meters (328 yards). In fact, at the Circuit de Spa-Francorchamps, drivers apply their brakes for 13.3 seconds per lap or just 13 percent of the total race time.
However, six of those seven braking procedures feature acceleration of at least 4.1 g (0.14 oz) with a couple of braking sections of over 5.3 g (0.19 oz). Braking distances exceed 110 meters (120 yards) in five corners, a level far beyond that at Circuit Zandvoort in a week’s time. However, the load on the brake pedal at the Belgian GP is low: less than 36 tonnes (35.4 tons) from start to the checkered flag, about 20 (19.7) less than at the Hungarian GP.
Turn 18 needs a big foot
Of the seven braking sections at the Belgian GP, three are classified as very demanding on the brakes, two are medium difficulty, and the other two are light.
The hardest for the braking system is Turn 18. The single-seaters arrive at 333 km/h (191 mph) and drop to 92 km/h (56 mph) in the space of just 134 meters (132 yards). Formula 1 drivers only need to brake for 2.78 seconds, but they have to apply a force of up to 207 kg (456 lbs.) on the brake pedal, a record high for the championship. They also have to handle a deceleration of 5.9 g (0.2 oz).