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Can we talk about them, I have questions..
1. Would they not be better mounted on the wheel axles?
2. Would it work to strap them to a helmet to stop your head (eyes) wobbling?
3. How long until we see one at a trail centre near you?
4. If you added one to a plane on a conveyor belt.....?
https://www.pinkbike.com/news/first-look-countersycles-tuned-mass-damper-for-mountain-bikes.html
Not sure about the TMD but i am thinking of the Fox Neo electronic suspension for next year.
1. No. You want the wheel to be able to move over obstacles (relatively) uninhibited with the frame being the element that’s calmed
2. Yes
3. Being mounted to a Santa Cruz as I type this
4. China syndrome
I think that the physics isn’t really addressed in the article. It’s essentially all about frequency response. It’s very interesting that it increases travel use
Putting it on the unsprung mass would give a very different response i think. I have seen a photo of one on a swing arm. No idea if that’s be better
Hoping for some answers from some one who really knows about this stuff
3. I've seen plenty of TMD's front mounted on the rider in a central position already at GT.
one on the front end here too
https://www.pinkbike.com/news/first-look-countersycles-tuned-mass-damper-for-mountain-bikes.html
oi, ssstu - you calling me fat ?!
I've a good mind to waddle over there and .. oooh, there's a Greggs
I was unaware that you were a honeymonster or a GT visitor.
[laughing winky rotund emoji]
3. I’ve seen plenty of TMD’s front mounted on the rider in a central position already at GT.
Oi, I resemble that comment
I've just tied a half ender in the middle of a bungee cord and suspended it in the front triangle to test this.
I'm convinced it'll make me faster.
Interesting thoughts here
basically, they might help,, but might make things worse. And not ideal for something as variable as a DH trail.
Really interesting stuff this, it seems to me a bit like a resonator in an exhaust pipe- getting it right is going to be damn nearly impossible for most people, but, you probably don't have to get it exactly right, you only have to get it so that it's on balance an advantage and that's got to be much easier. I reckon it might actually wokr really well for us dobbers who're probably more consistent in speed and what we ride, and also quite possibly we'd benefit from using them to tune for effects that aren't <really> that big of a deal, like chatter etc that fast guys just ignore but that freak us out. So there could be a lot of divergence between what works for pros and for us, much like suspension setup.
I like stuff like this that my first reaction is to go "well that's obviously bollocks" and then you dig a bit deeper...
matt_outandabout
Full Member2. Would it work to strap them to a helmet to stop your head (eyes) wobbling?
Quite possibly but you want your helmet to be as light as possible so as to not snap your neck and to reduce concussive brain injury (heavier = more dwell time at high forces = just as bad as hitting yourself harder.
The problem with tuned mass dampers is that they are tuned to a narrow frequency band. I wonder if a particle damper could be a better option as they work over a much wider frequency range?
This is a good paper on how they work in skyscrapers:
With resonant systems like this you generally want a low Q (inverse of resonance), so you get less peaky response over a broader bandwidth. That’s what happens with air resonators but to get that with coil springs I think you’ll need to introduce damping somehow - fortunately you need damping in a TMD otherwise it’ll just become excited to its limits and stop helping.
The natural resonance of the bike+rider system should be easy to measure with the right software and a phone (accelerometers!) taped to the frame. I was thinking it would depend on spring rate but I don’t think that can be the case because bigger rider’s bikes don’t behave like they have much higher natural suspension resonance, so the rider is both part of the sprung mass and also a secondary set of masses in series with the main mass connected via partially sprung linkages (arms and legs).
Can we talk about them, I have questions..
Tha ks for a headsup for a forum that doesnt just represent the same ten ****
Had quite a lengthy chat about Tuned Mass Dampers with Matt from Rimpact (who has been experimenting with them for a few years now) at Tweedlove earlier this year... Says he has plenty of scientific evidence to prove their effectiveness when tuned properly, and can make a decent difference even for the most amateur of riders... The key is, of course, getting the effective operating window setup correctly.
The tech comes from the F1 world for any who might not realise their significance. It's not back of a fag packet engineering certainly...
Of course the biggest issue, even if they were proven to make a decent difference, would be convincing most MTB riders to actually strap more weight to their bikes rather than remove it!
Anything that increases sprung Vs unsprung weight will improve suspension performance and a tuned mass dampener is effectively a way increasing the sprung mass but there are too many variables for the layperson to tune a mass dampener correctly. You'd be better off cable tying lumps of lead to the frame Chris Porter style.......or buying a (heavy framed) ebike
Of course the biggest issue, even if they were proven to make a decent difference, would be convincing most MTB riders to actually strap more weight to their bikes rather than remove it!
I think we all know how it goes by now. Within a year or two some dumbed-down version will be a must-have feature on pretty much any mountain bike you can buy. Journalists will rave about the buttery smooth progression they engender in suspension systems and how they cannot now imagine riding without a TMD, the abbreviation will become ubiquitous. People on here will swear blind that they have no idea how they ever managed to ride down a bumpy fire-road without one.
Next aftermarket companies will offer eye-wateringly expensive TMD upgrades that will quickly be superceded by the STMD - Specialized Tuned Mass Damper - 2.0, all your old forks, frames, shocks will be declared obsolete by the same journalists who believe that a £7k power-assisted enduro rig now means there's no future for human-powered bikes, because, why would you?
A couple of years later, t˙he whole thing will have been forgotten about in favour of the next high-tec, eeee-lectronic, very expensive performance gizmo component, and the tuned mass damper will be consigned to the passing fad trash-bucket of history. People will look back, shake their heads, and ask 'what the fluf****s was that alll about then?'
It’s possibly to make TMDs with variable tuning frequency (some are in that pdf) and I believe Fox has a patent on one. It wouldn’t be difficult to automatically tune one using accelerometers on the bike.
If you race DH or spend a lot of time at uplift venues it seems a good idea to reduce fatigue, especially as some of these loads going into the body aren’t brilliant for you, like using a chainsaw or pneumatic drill.
Actually, maybe an app on a phone that’s in your pocket is the answer? As long as the phone is attached firmly enough to the rider it’ll pick up the frequency range (within the TMD’s operating window) that is most in need of damping. It could then tell you to add mass or change the spring rate of the damper, and then remeasure once the damper has been manually tuned, and iterate round. It might be possible to tune the mass and spring rate so that the damping effect remains consistent, because the damping force will be proportional to tuning frequency, so if the spring rate goes up so will the damping as required.
It’s not for people like me, I ride hardtails much of the time! Doesn’t mean it’s snake oil though.
1.8 to 1.5 taper steerer forks for '26 or '27 are being touted as the way fwd for internal TMDs according to someone at Taichung Bike Week recently - placed where they need to be with rotational inertia neutralised and max effect on the front suspension. 1.8 was meant for e-bikes and with e-bikes becoming the focus for FS MTB models in most brand's ranges .. it seems we may have a new head tube spec on the way.
Of course this may or may not be true ; )
“ .. it seems we may have a new head tube spec on the way.”
You betcha
https://www.rimpactmtb.com/post/rimpact-tuned-mass-damper-development-blog-part-1-concept
more info to chew on.
If you want a useful phone app, Physics Toolbox is excellent. It uses your phone sensors to do all sorts of light, acceleration and sound based measurements.
That’s great! I’m now going to have to ride some drops on my hardtail and full-sus to compare G forces…