Ducati 851, Bimota YB4 and Honda RC30. 30 years ago the bikes in SBK were much different. And so were the brakes.

4/12/2018

 HEAVY BIKES, CAST IRON DISCS, 2-PIECE CALIPERS AND LONGER BRAKING DISTANCES.

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Thirty years ago, more specifically, on April 3rd, 1988, the Donington Park circuit (Great Britain) hosted the first World Superbike race. Competing that day were Marco Lucchinelli, Fred Merkel, Davide Tardozzi and Joey Dunlop. The top bikes were the Ducati 851, the Bimota YB4, the Honda RC30 and the Suzuki GSX-R750. Some were already equipped with Brembo brakes: in fact, in the factory derivative series, our systems have never been absent. It is not by chance that the bikes equipped with Brembo brakes have won all 30 of the World Superbike Manufacturer Championships held so far, as well as 27 World Superbike Rider Championships.

 
 

On that day 30 years ago, no less than 39 riders lined up on the starting grid for Race 1: Davide Tardozzi (Bimota) managed to finish the 30 laps first with an advantage of one second and 90 thousandths over Marco Lucchinelli (Ducati) who had even done the fastest lap. The two Italian riders also battled for Race 2, but in the end Tardozzi crashed. So, Lucchinelli won with 9 seconds and 350 thousandths ahead of Fred Merkel (Honda team Rumi). At the end of the year, the latter would become the first World Superbike Champion. In order to properly celebrate the anniversary of the first race, we decided to compare the braking systems of the current Superbikes in the Championship with those on the bikes that rode out onto the track 30 years ago. There are six main differences.

 

​1) The brake disks: small and flimsy


The Ducatis, Bimotas and Hondas in 1988 used cast iron discs that were 0.20 inches thick and 11.42 inch or 12.6 inch diameter, depending on the event. These were the most economic solution and they did not need to be brought up to temperature in order to be used. After all, cast iron is a fragile material and the combination with increasingly more aggressive friction material led to it being abandoned early in favor of steel and later carbon. However, carbon discs were banned in 1994 in order to contain costs and steel discs were brought back. In 2018, the Superbikes used 13.23 inch diameter steel discs, but there were still those who used 12.91 inch discs. Depending on how hard the races were and the riding style of the riders, the thickness changed from a minimum of 0.22 inches to a maximum of 0.28 inches.

 
 

​2) The brake calipers: two halves and not as stiff


In 1988, the Superbikes used 2-piece calipers secured with 4 joining screws. The system made up of 2 mechanically coupled semi-calipers had clear limitations in terms of rigidity and suffered form the different technical dilation of the aluminum in the caliper and the screws. To solve these problems, in the latter half of the nineties, Brembo introduced monobloc axial brake calipers. A few years later, these were in turn replaced by radial calipers: the mechanical stress was lower and therefore elastic deformation was also reduced, with clear advantages in braking sensitivity. Sixteen of the 2018 World Superbike Championship riders used Brembo nickel-plated billet aluminum radial calipers. ​

 
 

​3) The brake pads: glazing and fading lurked


Some of the 1988 World Superbike Championship riders used pads made of organic materials, others sintered pads. The former benefited from responsive braking as early as the first turns and did not have problems with the rain, but they had to go through a thermal breaking in order to adapt perfectly to the disc. The organic pads, however, were lower performance, high wear at high temperatures and were susceptible to glazing: to prevent this, some riders used sintered pads which were more costly by nature. The make up of the latter was much different than that of the Brembo Racing Z04 pads used in recent years in the World Superbike Championship: their consistent performance at high temperatures prevents the Fading effect, in other words, the deterioration of performance that was not infrequent in 1988.

 
 

​4) The brake master cylinders: lots of space, not very effective


Thirty years ago, they were still using axial brake master cylinders in Superbike: besides being made through casting, they had other limits. They were rather bulky and part of the force applied by the rider was lost because the body of these calipers is subject to bending. A few months later, radial brake master cylinders made from billet with molded levers appeared, already used successfully in World Grand Prix Motorcycle Racing. Modern radial brake master cylinders in a position transversal to the handlebar guarantee the absence of wasted energy, because the force of the rider's hand on the lever and that of the lever itself on the piston act in the same direction.

 
 

5) Braking: longer distance and tending toward worsening


The combination of axial calipers and master cylinders, cast iron discs, organic pads and the characteristics of the 1988 bikes made braking distances at least 25 percent longer than modern ones: the Ducati 851 had a curb weight of 392.4 lbs, the Bimota YB4 396.8 lbs and the Honda RC30 407.9 lb, whereas the Superbikes in the 2018 World Championship weigh 370.4 lbs. Over the last 30 years, Brembo has introduced various product, material and production process innovations: the result is a drastic decrease in braking distance. Furthermore, with the same amount of force applied to the lever, at the dawn of the Superbikes, different braking was achieved since performance was susceptible to deterioration during the race. Today, on the other hand, thanks in part to increasingly more advanced brake fluid, the range of use is higher and response more consistent from start to finish.​

 
 
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6) Maintenance: more frequent


Brembo has always given great attention to the reliability of their products. However, in 1988, rebuilds were more frequent than they are today because the internal components of the calipers, from the pistons to the sheet metal, all the way to the rubber parts, did not provide the same structural and resistance characteristics as modern materials. Consequently, the calipers and master cylinders were returned to the factory more often for periodic inspections and the replacement of the perishable materials. Today, on the other hand, a caliper used in the World Superbike Championship is rebuilt every 1.500/1.800 miles and can even last a couple of seasons. However, this interval is reduced as a precautionary measure in the event of a crash and even in a scenario where the caliper has reached temperatures (that can be measured with thermotape) higher than 392°F. ​

 
 

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