MotoGP Mass Dampers Explained | How Teams Control Chatter & Vibration

Now have these mass dampers in the tail section and I'm, it, it, mass dampers aren't talked about a lot in the tail section. And I wonder if these two things are going to work together or how that's going to play out, because it's interesting to me. So my understanding of the mass damper is it is intended to, should we, should we explain what a mass damper is really quickly for those who may not know? Yeah. So in its simplest terms, if you take a mass of some kind and you put it between springs or some sort of suspended contraption, and these get, these get really wild sometimes, the designs they come up with, the idea is as you deliver an input to it, the mass damper, the mass is going to react differently than the solid structure. So take your motorcycle, for example, think about the subframe. If I all of a sudden get a hit or an oscillation, the subframe is going to react quickly based on just what the suspension and tire can absorb, the frame's going to take the rest of it. That mass damper is sprung typically, and it is going to have a different rate of reaction to whatever it is. The idea with it is it's the fact that it is reacting at a different frequency, a different speed is going to cancel out some of the other motions that are happening. So where this gets used in motorsport typically is if you get to a point where you are experiencing chatter, which is a weird phenomenon, and it's very difficult to describe how it comes about sometimes and what causes it, but in simple terms, imagine your rear tire has so much grip that it isn't able to just spin smoothly. Right? We picture tires like dirt track riders or flat track riders, where once it breaks traction, it's just this nice, gentle glide smooth through the corner. If you have a really grippy tire and really grippy surface, it doesn't just gently slide and drift through the corner. It grips, slips, grips, slips, grips, slips, and that almost creates this shutter because it happens at such a high frequency that it'll create this pulsing shutter into the motorcycle itself. And that can happen to the front or the rear. Okay? Now, when that happens, effectively the rear tire grips, spins, grips again, but sometimes it'll get so violent that the tire starts to leave the asphalt and where some of these hop, harshly leave, right? And you'll get this juddering, hopping feeling. And you can see that sometimes in the slow motion footage on MotoGP and it's in like whatever they're catching, like 2,500 frames per second. And you can see this violent, though, carcass flexing and deforming it. Yeah. There's contacts that shrinking and contracting it. There's a great clip. If you go look on YouTube, you can find it. It is Jack Miller last year on the KTM at Motegi and he's breaking into a corner. And Motegi has a lot of hard braking entries and he's breaking into a corner and it's the same phenomenon, but it's effectively in reverse because he's braking, they're trying to brake with the rear tire and it's so grippy. It won't just slide on the entrance. So it grips and skips and grips and skips. And it's getting so violent that you see the tail section bouncing in the tire, leaving the ground. It's always amazing when they do those super slow-mo's because you watch the carbon fiber flexing on the bodywork. That's how violent these, these can be. And that's, and that's where the mass damper comes in, right? And mass dampers, from what I understand, they were originally put in skyscrapers to counteract the, the swaying. They still are. Of the, and that's kind of, and so now we're taking it to this small little thing in the tail section of like the Ducati has it, KTM has it now. Or do they not? They were playing with it. Honda has it. They'll never tell you. They'll tell you. You, you can assume that they have it. If you look at the tail section and it seems shockingly large. Yeah. Like the Ducati obviously has a mass damper. They developed it. They brought it to MotoGP. We know it's in the Ducati. Correct. Yeah. Now where this comes from is every, we're going to get a little nerdy here for a second, every single thing, this chair, this table, your watch, everything has a natural frequency, which means it's the frequency in which it wants to vibrate at. Right. Now there's different modes of frequencies. So there's actually multiple, but you have these natural frequencies. If you give something an input at a similar frequency or the same one, rather than the amplitude of the motion damping out over time and calming down, it sometimes accelerates and gets worse and worse and worse. Okay. So that's what these natural frequencies are. When, when people are designing a car, right? The engineers are measuring and trying to understand what are the natural frequencies of your components, but also of the assemblies and how do we make sure that those do not line up with a frequency input from the tires or from the engine or transmission or what have you, because if they line up, you wind up with really miserable conditions for the drivers and the people inside the vehicle. Okay. We probably all had that, that, that Toyota. Everyone, everyone's experienced. And you go, Oh, it's at 63 miles an hour. I get a terrible shredder in the wheel. And then at 70, it's gone. That's exactly what you're experiencing. The same thing happens to the motorcycle. And so the idea is they try to understand what is, what, what are the natural frequencies that occur within this bike? And how do we react to that or compensate with these mass dampers? But if you think about it, all of these, think about the amount of adjustments that can happen to a vehicle that would adjust its natural frequency. Even things like, Oh, we move the axle further back in the adjuster. We change the swing arm pivot. We used a thicker axle instead of a thinner one or wheel material. Like all of these things add up to whatever those natural frequencies are in the bike. So tons of things. And that's why that's partially why these chatter and vibration issues are a nightmare to chase down. Cause it's so hard to guess what's going to cause it or when it's going to go away because they're constantly fiddling with everything. So the mass damper idea is often, oftentimes the mass damper is tunable in a sense that I could have different springs supporting the mass. I could do preload on the springs. I could do different masses. I could put the mass in different places. Jingles straight up and down. You know, the sky's the limit, right? And you're even seeing now on the swing arm of the Ducati, Mark's had it in a couple of races. There's a funny little cylinder right on the back. Again, I don't know what's inside that little cylinder. But it's a little cylinder in fluid. It's a little damper. I would assume it's a little mass damper on the, on the edge of the swing arm. It could be a sensor for all I know, but that's what I assume it is. Um, but that's the idea with these mass dampers is to try to tamp out whatever the weird vibration is. Right.