Misano is a relatively technical route. For example, turn 6 is a place where there is a lot to do for a rider in the MotoGP category. It's a tricky corner, in which the drivers barely touch the brakes. It's one of those corners where you have to sacrifice entry to favor exit, which is really crucial. This is also a great place to use the Ride Height Device, which we will detail with these few photos.
A development from which the competitors are inspired, but which is to the credit of the men of Ducati, itactivates the leveling system while driving. A variable geometry chassis is one of the biggest dreams that MotoGP engineers have sought to realize for decades.
This device is an evolution of their Holeshot Device, which allows them to use it while the motorcycle is moving. It works by activating a small lever which allows the rear of the motorcycle to lower. They use it when exiting corners where the bike is fairly straight and where they can accelerate strongly. The science behind this has to do with the center of gravity and the force of the chain acting on the rear suspension and rear tire. The result is that when Ducatis drop the rear end, they can accelerate harder and earlier than they could without the device.
When the Suzuki was not equipped with it, the Hamamatsu Technical Managers estimated that they lost 0.3 to 0.4s per lap without this device!
In this photo, we find the KTM rider, Miguel Oliveira, at the exit of turn 6. The Portuguese had a better weekend at Misano than the last ones, and it was regrettable to see him retire in the race, but there It’s a safe bet that in Portimao, he will want to put on a show in front of his home fans.
On this lap, Miguel Oliveira does not actually use the Ride Height Device, which helps give us a reference. So we can see what the back of the machine normally looks like compared to the following photo.
The Ride Height Device is activated via a handlebar control, which activates a small hydraulic can on the rear suspension. When activated, it allows the rear suspension to change shape, causing the rear of the motorcycle to lower and change the geometry of the entire chassis.
Same session, same corner, almost exactly the same piece of track, but this time with Danilo Petrucci. It uses the Ride Height Device, which is pretty obvious to see because the rear of the bike is lowered.
Another thing to note here is that KTMs have a very large diameter rear brake rotor. On other MotoGP prototypes, most of them use smaller rear discs. Larger disc diameters generally give more stopping power, but they can also change the feel for the rider.
In this photo by Pecco Bagnaia, we can see how the Italian driver is trying to shift all his weight as far as possible. We often see riders doing this in wet conditions. Coming out of corners, they will try to put as much weight as possible on the rear tire to give it as much grip as possible.
Compared to the other drivers, Pecco Bagnaia sits further back and straighter than most in this particular situation. It's likely that the strong downforce created from Ducati's aerodynamic package allows it to sit further back without experiencing as many wheelie issues as its competitors.
In this photo, the motorcycle is sitting on the ground. Honda lagged behind its competitors in the development and use of the Ride Height Device, particularly Marc Marquez. When he first tried it, he didn't seem to like it, so much so that for a while he didn't use it. Now he uses it regularly and this picture clearly shows how much he lowers the rear of the se RC213V.
If we compare the photo of Marc Marquez to this one, where Takaaki Nakagami who, on this tour, does not use it, the difference is obvious. Here, we observe a significant space between the rear wheel and the rear buckle of the RC213V.
Takaaki Nakagami is now the only Honda rider to stick with the 2021 chassis, which features a carbon part glued to the main beam. 10 days ago, at Misano, all other Honda drivers used the “Assen” chassis.
Here is the brand new World Champion, Fabio Quartararo, also exiting turn 6. When teams started using the Ride Height Device, they found that they were falling too quickly. Rapidly lowering the rear end of the machine would disrupt the balance of the entire machine, causing the suspension to bounce, making it unstable.
To get around it, teams further developed these devices, so that they lower much more slowly than before. But even with this development, they still found that they could sometimes destabilize the bike and a lot of that was due to when the riders activated the device itself.
So the next step in their evolution that we're currently seeing with Ducati and Aprilia is to make them automatic. In fact, Ducati and Aprilia have developed a system that relieves the rider of the responsibility of activating the Ride Height Device at the right time. When the forks relax as much as possible when exiting a corner, the technical teams have developed a hydraulic system which triggers a valve and activates the Ride Height Device.
But if it activated every time the forks extended to their full length, that would be a major problem. So, they have a built-in safety: the rider must push/press a button/lever to “arm” the system, so that the Ride Height Device only activates the next time the fork is fully released.
It's a clever mechanism and it shows how far this device, first presented by Ducati, has been developed.
Photos: Dorna Sports
