From 305 km/h (190 mph) to 74 km/h (46 mph) at Estoril. The Brembo Superbike data

5/25/2021

The three benefits of the Brembo caliper for Superbikes, its use in Portugal and the finned calipers for street-legal motorcycles

A week after MotorLand, the World Superbike championship remains on the Iberian peninsula for the round at Estoril Circuit, in Portugal, back on the calendar since last year after a 27-year absence. According to Brembo technicians, who work closely with 17 World Superbike riders, it is a demanding circuit for the brakes.

On a scale of 1 to 5, it earned a 4 on the difficulty index because it is a combination of long straights, fast turns and hairpin corners that must be taken at low speed. Grip might be low because, being close to the ocean, there is often wind that blows sand and dust onto the asphalt and creates problems in riding.

The three benefits of the new caliper 

One of the big Brembo innovations this year is the one-piece caliper made entirely from billet aluminum that stands out because of the fins on the outer body and two other, less visible, improvements. Inspired by the similar solution used in MotoGP on the GP4 caliper, the fins improve the braking system’s thermal exchange, contributing to cooling it.

The caliper for Superbike has a 4-piston radial mount 34 mm (1.33 inches) in diameter and it features a system that amplifies braking torque: With the same force applied on the lever, the braking torque is greater. It also has the anti-drag system that reduces the residual torque effect, using a spring device to prevent forces from appearing which slow the motorcycle when the brake is not being used.

Fins for street-legal motorcycles too

Those who think that fins are a privilege reserved for racing motorcycles are dead wrong. In fact, the Brembo GP4-RS caliper has fins around the pistons that increase the surface exposed to the air by 30 percent compared to a conventional caliper. This is no small difference in an area subject to high thermal stress.

Besides this advantage, the Brembo GP4-RS has others, beginning with the 10 percent lighter weight than the renowned M4 Monobloc, thanks to a highly complex casting technique. No less important is the higher rigidity, thanks to the ribbing on the front section of the pistons that hinders deformation in the most critical braking maneuvers.

Find out more about the Brembo GP4-RS caliper, the dominator of the summer.

A ton of force in the race

On 10 of the Portuguese track’s 13 turns, the Superbike riders use their brakes for a total of almost 26 seconds per lap, which is 27 percent of the race, identical to the value at MotorLand. However, the load on the brake lever is much higher: 985 kg (2171.55 lbs) from the start to the checkered flag, compared to 725 kg (1598.35 lbs) at Aragón.

On 6 of the Estoril Circuit’s 10 braking sections, the speed reduction during braking does not exceed 80 km/h (50 mph) and the braking distance does not go over 75 meters (246 feet). However, at 3 other points, deceleration exceeds 140 km/h (87 mph), the riders are subjected to at least 1.4 Gs and the braking system operates for more than 3 and a half seconds.

From 305 km/h (190 mph) to 74 km/h (46 mph) in 5 seconds

Of the 10 braking sections on the Estoril Circuit, 3 are classified as highly demanding on the brakes, 4 are of medium difficulty and the remaining 3 are light.

The most demanding one is the first corner, partly because of the 986 meter (3,235 feet) straight leading up to it. The Superbikes arrive at 305 km/h (190 mph) and, thanks to their brakes, drop 231 km/h (143.5 mph) all the way to 74 km/h (46 mph) after 235 meters (771 feet) of braking. To achieve this result, the riders use their brakes for 4.9 seconds and withstand 1.5 Gs of deceleration.