Dear MOby,

I was reading an article on Ducati’s recent success in Moto GP, and it mentioned that Duc was the first manufacturer to use mass dampers. How are mass dampers used in motorcycles?

Kenneth Moore

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Dear Kenneth,

We had to interrupt MV Agusta Technical Director Brian Gillen’s holiday in Malta to answer this one. He says:

“Mass Dampers appeared for the first time in racing in Formula 1 at the Monza GP in 2005, with Renault, and went for the most part completely overlooked by the rest of the paddock. That soon changed as it became clear that this system was an integral part of Renault’s dominance, and as a result mass dampers were subsequently banned by the FIA after the French GP in 2006.

“What is a mass damper? An often overlooked part of the suspension system is the tire, which acts as an “underdamped” component and is not part of the suspended mass of the motorcycle. When the tire encounters a bump it responds similarly to a basketball bouncing, with the final effect of reduced grip. The mass damper is a weight (disk) suspended in a cylinder between two springs with different spring constants positioned with the stroke axis parallel to the direction that the system needs to be damped.  

Illustration by Rswarbrick at English Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=40435208

“How it works: Imagine dropping a basketball on the ground, with the result that it keeps bouncing slightly less with each bounce until it comes to a rest. That’s your tire. Now, if the basketball had a mass damper inside (calculations and tests required to tune the system), the ball when dropped would effectively remain glued to the ground with only a few small bounces.

“Why was it a major advantage in F1 cars and not currently used on motorcycles other than in some tests (Ducati…)? F1 cars primarily use aerodynamic downforce to generate grip, and the mass damper helps attenuate tire vibration, translating that aero load into grip.

“With motorcycles the dynamics are different; motorcycles use both bike and rider weight transfer to generate grip. F1 cars are tuned to have minimum amounts of pitch and roll, where motorcycles rely on pitch and roll to brake, accelerate and turn. For this reason, the application of a mass damper on a motorcycle is very complex, as its functional envelope is limited to the vertical direction of the mass axis. With current GP bikes exceeding 60 degrees of lean angle, it’s difficult to decide when and where on a racetrack you could optimize its function, where everywhere else it would simply be moving ballast. On a bike, a mass damper is an attempt at a simple solution to a very complex problem.

“There isn’t any visible evidence that they [Ducati] are currently using a mass damper system on the race bikes, and all of the photos of the test bikes are from a while ago. That said, I don’t believe the idea has been completely abandoned and I would not be surprised to see it make an appearance on the front end of the bike in the near future.

“Great race today [British MotoGP] and another step towards the Italian holy grail of achievements… Italian bike winning the championship with an Italian rider!”

Thanks, Brian!

PS: There’s a great story here by Mat Oxley, re. pre-season Ducati “jounce damper” testing if you haven’t already seen it.


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  • Starmag

    Some masses can’t be dampened. Damp maybe…

    https://i.ytimg.com/vi/JNw4mXszoYM/hqdefault.jpg

  • Old MOron

    Good question, Kenneth.
    Good answer from Brian Gillen. Not the first time he’s offered technical expertise, IIRC. Do you suppose he would appreciate being an honorary MOron?

    • john burns

      maybe best for a big shot at MV Agusta to keep MOron ties to oneself really…

      • Old MOron

        Ha ha, he must’ve complained to you already. Keep up the good work, JB. We won’t make you divulge your sources.

  • Mister X

    Although Mass Damper usage likely predates the example here, the 1962-69 Chevrolet Corvair convertibles had a Mass Damper mounted at each extreme inner corner.

    It was an oil/spring/weight inside a sealed tube about a foot long, by 8 inches diameter, that bolted to the body panels.

    Apparently these were added because cowl shake was a real problem, due to the Corvair top being removed, thus reducing body stiffness.

    • TonyCarlos

      Good post. Lots of that vintage convertibles used those devises. Before chassis engineers got hip to stiffening, those dampers provided a good bandaid.

  • TonyCarlos

    Illuminating article, but a few words about what the heck that photo is supposed to be showing would be helpful.

    • john burns

      gee, I kinda thought that’s what the whole article was explaining? Pair of mass dampers in the tail of a Ducati MotoGP bike.

    • Born to Ride

      The photo is a spring mass damper diagram. The squiggly lines are springs, the pink lines with the piston-cylinder thingies are dampers, and the big blocks are the bodies whose relative motion we are interested in tracking. The system pictured would be an MDOF system, meaning that there are multiple degrees of freedom within the system because there are multiple masses. A simple system without a secondary mass providing modal damping would look like this
      https://ecourses.ou.edu/ebook/dynamics/ch10/sec102/media/d0221.gif

      Any further explanation would require you to have a firm grasp on Newtonian mechanics, but it is a very interesting subject to study. Albeit quite tedious.

      • TonyCarlos

        I appreciate your effort, BtR, but you’re addressing the wrong issue. The diagram is clear to me. I’m a mechanical engineer. I’ve spent enough time with sprung weights, and under damped systems.
        My question was not about the diagram, but the photo. After staring at it long enough, I can sorta figure it’s a bike tailsection, with what might be an center, under-seat exhaust exit. The rest is a mystery.
        After reading the article, one could guess that the twin CF beer cans are probably a part of the sealed sprung mass system, but as I first said, a few words of explanation would have helped.

  • Donnie

    Hmm, I wonder if they could use some sort of gyroscopically controlled mechanism to help out at varying lean angles? Gotta think on this one.

    • john phyyt

      I had a different idea. How about an electromagnetically controlled weight which could be flung rearwards during Braking and forwards under acceleration. Maybe help move rider even more than s/he can now.

      • Born to Ride

        Is this a serious question? Because I can elucidate the pitfalls of such an idea from a mechanical standpoint, but I don’t wanna come off as a dick if you were joking.

        • john phyyt

          Half serious. I actually thought this was out-lawed. What do you see as the major areas of concern.?
          Could maybe pump fuel around or move engine. I do remeber in F1 where undue chassis flex and controlled weight movement was banned.

          • Born to Ride

            Well, you had previously said a magnetically controlled counterweight that could move a significant mass to change the weight bias under acceleration and braking. Such a system would be impossible to implement for a few reasons. For one, the generation of enough electrical current to power induction coils capable of moving a large mass of ferrous alloy, presumably steel, would vastly exceed what the charging system on a motoGP bike produces. Furthermore, it would have to work doubly hard because you are trying to resist its natural kinetic energy. Let’s say you have a 20lb pound chunk of steel on a rail 18-24″ long, and there was magically no packaging concerns fitting that into the dimensions of a racebike

    • Born to Ride

      This is unnecessary. The dampers are interested in controlling the travel of the swingarm relative to the body of the motorcycle. Because the swingarm pivot is “rigid”, it forces the wheel to travel along a fixed path that is aligned with the angle of lean. Therefore adding degrees of freedom to the damper that the chassis does not possess would be counterproductive.

  • kenneth_moore

    Wow…thats quite a complex system. I won’t pretend to fully understand all of it, but I can see how much harder implementing the concept on a bike would be vs. a car. Thanks for the info!