Engineering nerdery is one of my favorite rabbit holes to dive into. But I was gobsmacked by a single infographic I saw while attending the Circuit of the Americas round of MotoGP and that was Brembo’s brake rotor options.
I’m sorry but did you know Brembo offers teams a whopping 11 options for just brake rotors?
If you’ve ever been to a Formula 1 race, you’ll likely have seen the series’ tire option infographic, i.e. the lineup of the possible tires for a given race. They include a Soft, Medium, Hard, and Rain compound and are lined up along some invisible line and thrown up on one of the jumbotrons. I’d like you to picture that, but instead of tires, you have brake rotors, and instead of four options, you have 11.
I don’t know why, but I sort of expected everyone to run a pretty standard setup for all the races. The bikes don’t change all that much from race to race, so why would the braking systems have to? But this is top-tier racing and after talking with Brembo’s Mattia Tombolan at the track, why wouldn’t teams and their engineers look for advantages wherever they can?
“So basically speaking, carbon material has a specific range of temperature where it has the correct friction coefficient,” Tombolan tells me, adding, “If you're playing too hot or too cold, you won't have the correct friction coefficient.” And to find that correct friction coefficient for each race track, bike weight, bike power, and rider, there are 11 different brake rotor options offered in every race, and even more combinations as teams can pick and choose between them.
The rotors themselves come in two different materials; carbon and steel. And the two come in five different sizes separated by those materials, with the carbon rotors—purely for the front wheels—including two rotors in 320mm, three in 340mm, and one 355mm, all of which have different properties and are used for specific reasons and tracks.
While there’s overlap in the carbon rotors, according to Brembo, the 320mm to 340mm rotors are designed more for low-demand braking tracks, while the 355mm to 340mm rotors for high-demand braking tracks. “For example, this kind of disc (holds up a 355mm finned carbon disc), where you can see a lot of fins, you can deduce that it's designed for high braking circuit, because in this way you can, let me say, dissipate very fast the heat and stay in the cool part,” says Tombolan, continuing, “Otherwise, when you have a not so high demanding truck, like Assen or Phillip Island, when you don't brake enough, you have to keep the temperature, keep the heat in order to make it work.”
But as teased, each of the rotors are also designed with those specific applications in mind, with three optional designs offered for each of the diameters, including; Finned, High-Mass, and Standard. And that’s how you get your 11 different options.
According to the company, most teams swap between the High-Mass and Standard setups throughout the year, but the Finned options are great for tracks that are both hot and have successive high-speed braking zones. Think Japan’s Motegi, with Tombolan telling me, “You have hard turns close to each other…so in this part (holds up a track map of Motegi) the temperatures build up, build up, and this is the turn, that’s where we're struggling.”
All the rotors, however, are 8mm wide, as that doesn’t change from rotor to rotor. They do, however, gain or shed weight depending on setup, as “weight varies between 1kg (2.2 lbs) and 1.4kg (3.08 lbs), depending on the diameter and specification used,” according to Brembo.
But the insanity of options grows as teams have further options to customize their brake packages, as Brembo also offers different pad materials and sizes, as well as different calipers, caliper pressures, and pistons. Some teams even run dual-caliper setups to give riders more options, including having a handlebar-mounted brake actuator (either thumb or lever) that controls the rear brakes of the motorcycle.
Teams also control what their individual brake shrouds look like to both maximize airflow and both trap and reduce brake heat. “Also the cover, you will see it's very helpful, helpful for the team to let me say manage the specifics of disc, because you don't want to change every time the discs,” says Tombolan, continuing with “So you keep the same disc and maybe you play a little bit with the cover. They have a lot of covers, around three or four types. Originally the cover was developed to protect the disc for the water in wet conditions, because carbon material is not very friendly with water. It's hygroscopic, I don't know if it's the English term, so it tends to absorb it, and so it will lose its property.”
But this adds to the variability within just this single part that inevitably affects the overall performance of the rest of the motorcycle. That’s just wild to me.
All-in-all, there are over 55 different setup possibilities just in terms of the brake rotors for a MotoGP bike. That’s not including all the other parts of the braking system. And, honestly, that’s mind-blowing.
