Author Topic: Anyone using/tried Bontrager Buzz-kill harmonic dampers?  (Read 9823 times)

Danneaux

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Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« on: September 23, 2012, 05:54:41 am »
Hi All!

While looking at handlebars this evening, I came across a product that is new to me and is causing a stir on various blogs and review sites.

It is the Bontrager Buzz-kill, a set of bar-end plugs intended for drop handlebars. Available to two versions (alu and brass), these are slugs of metal suspended in a viscoelastic matrix, intended to counter high-frequency road vibrations -- the kind that makes your fingers blur when you spread them. They're adapted from products made by the Mathews Bow company: http://mathewsinc.com/product/custom-damping-accessories/



Has anyone used or tried a pair? If so, how well did they work? Apparently, they've been on the market for a year or so. Most of the reviews I've found paired them with carbon forks, so it is a bit hard to tell if they might be a benefit with steel forks. I know a number of our members are dealing with hands made tender by arthritis, and after a day of yardwork, mine keep cramping, drawing my thumbs to the palms. Something like this sounds very appealing at the moment!

Bontrager (Trek) has an overview and details here: http://bontrager.com/model/04579
Custom Google search for reviews here: https://www.google.com/search?q=bonrrager+buzzkill+eview&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:unofficial&client=firefox-a&channel=fflb#hl=en&sugexp=les%3B&gs_nf=1&pq=bontrager%20buzzkill%20eview&cp=20&gs_id=9&xhr=t&q=bontrager+buzzkill+review&pf=p&client=firefox-a&hs=EYK&rls=org.mozilla:en-US%3Aunofficial&channel=fflb&sclient=psy-ab&oq=bontrager+buzzkill+review&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=3e1960d58e8957d2&biw=1173&bih=610
(Sorry, TinyURL is down at the moment; will replace this with a TinyURL later).

Best,

Dan.
« Last Edit: September 23, 2012, 05:56:59 am by Danneaux »

NZPeterG

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #1 on: September 23, 2012, 08:10:32 am »
Hi Dan,
Road Motorcycle's come with the damper in and they work on Motorcycle, So would work on Bicycles too!
You can also switch to Ti Handlebar which also work well to damping road buzz.

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triaesthete

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #2 on: September 23, 2012, 06:12:51 pm »
Hi Dan
like Pete says they've had them on motorcycles for years. Thing is though they are (properly done) harmonically tuned to damp out high frequency secondary vibrations in the (high revving) motor. It would be interesting to see what they do  for lower frequency road buzz that larger profile softer tyres and or carbon forks and bars don't.   I  wonder if stuffing the bar ends with Plasticine would have similar effect.
Are you going to try some?
Intrigued
Ian

Danneaux

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #3 on: September 23, 2012, 06:36:03 pm »
Hi Pete! Hi Ian!

<nods> Yep, I've seen these on motorcycles as well, and harmonic balancers are a common item on automobile crankshafts.

The thing is...their mass seems too little to adequately damp the vibrations on (relatvely heavy) touring handlebars and when used with already large tires, heavy rims, and a heavy steel fork and frame.

Looking at the masses involved, it seems they're best suited for carbon bikes, carbon forks/steerers, and carbon handlebars, where their mass would have a greater damping effect compared to the overall structure. The other thing is they don't appear "tunable" for a specific purpose or frequency. I think they missed a bet by not putting the damper mass on an adjustable moment arm.

Quote
Are you going to try some?

At this point, no...not in this form, but they do get me thinking about how a handlebar bag might work for that purpose. Ortlieb handlebar bags are constructed (plastic frame) so they are allowed a certain amount of "bounce" in terms of restrained vertical movement under load and in response to pedaling dynamics and road surface. If that could be "tuned" to serve as a harmonic damper, it would be great. The needed mass is there, the location is about right (especially if mounted to the 'bars rather than a T-bar), and the basic movement is correct for this purpose. The Folder I'm building has a bit of this in the suspension stem I've made. It uses an elastomer puck under compression, and not only provides rider suspension, in my testing, it also absorbs a lot of vibration through hysteresis of the elastomer material.

On second thought, the bag's mass is probably too great for the high-frequencies of these sorts of vibrations. Hmm. I need to give this more thought!

Quote
I wonder if stuffing the bar ends with Plasticine would have similar effect.

I think the Plasticene would have to move within contrained limits and not just sit there. Otherwise, a person could just put a few lead sinkers or loose shot inside behind the bar-end plugs and call it good.

The bane of American cyclists is chip-seal. It is an increasingly popular -- and cheap; there is a correlation -- way to resurface roads. Basically, hot tar is spread on the existing road surface, fine pea-gravel is rolled on it, and then traffic throws-off the excess, usually to pile in windrows on the bike lanes. When all the dust has settled, what is left is a very rough surface that goes far to produce hand-numbing, high-frequency vibration. Nearly all of this is resolved with proper, traditional, long-lasting and expensive paving techniques, something we're seeing less and less as budgets become more constrained.

A lot of handlebar vibration-dampening results from the tires used and the pressures they run for a given cross-section. If we could all just get with the plan and follow Andre's lead, we'd have it made. He's just that little enlightened bit ahead of us all with his balloon tires. Next time a very distinguished-looking gentleman passes me on his bicycle -- especially downhill at crazy-steep lean angles -- I'm looking twice to make sure isn't Andre!

All the best,

Dan.

triaesthete

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #4 on: September 23, 2012, 09:05:23 pm »
Dan we've had "chipseal" here for years as it is a cheap, not careful, way to restore friction levels on polished road surfaces. ( It covers the insides of pot holes beautifully too  ::).

This seems to me to give a vibration with a strong vertical component (nano washboard?).
Bar end weights on bikes are usually direct mounted  and simply tuned by weight to eliminate middle of the rev range secondary vibrations as they appear at the handlebars because this usually corresponds with cruising speed. (harmonic resonance displacement/disruption rather than damping?) These vibes really give numb as opposed to battered hands. I know from experience >:(

I would hazard a guess that strong and therefore rigid heavy touring components eliminate resilience and "give" found in lighter parts. The small but frequent vertical movements therefore batter the rider more directly. Attrition ensues. I found this to be the case when using an unloaded Sherpa for day rides. It was just too stiff for comfort, even with fattish tyres and 3 layers of bar tape. I expect loading it up as it was designed to be would force it to give a little....

I've tried a carbon bike and it really deadens small road feedback, even on 23mm tyres. Some say carbon bikes feel dead to ride as a result of this property but I liked it.

We need a noise vibration and harshness (NVH) engineer on the case.

cheers
Ian



Danneaux

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #5 on: September 23, 2012, 10:13:30 pm »
Hi Ian!

Rather than just saying "me too", I'll put it more elegantly --

I agree with everything you said, and wish I'd written it myself!  :D

Very nicely stated, all you wrote; a very neat piece of work!

I think you raised an excellent point about the relatively harsh ride of the unladen Sherpa compared to lighter-duty touring bikes. When asked to describe my own Sherpa, I have often responded it felt like a "heavy-duty" touring bike. The Nomad is that, and "more" -- setup with my preferred drop handlebars, I would describe it as a "super-duty" touring bike. While perfect for my needs and intended use, I can see it easily being "too much bike" for many who use it for its intended purpose only rarely.

It is a bit like how pickup trucks are rated for loads here in the US. A truck intended for general use will have a 3/4-ton rating and a lighter, compliant suspension. A heavier-duty model intended for really hauling things will be rated for 1 ton payload capacity, and have harsher, uprated springs and suspension components. A "Super-Duty" pickup (Ford actually markets some with this label) will have 1.5-ton capacities, and will ride like, well, a truck...unless heavily laden. They're not going to be as much fun for trips to the grocery or dentist's office but will be ideal for hauling a load of hay to scatter in the cows' winter pasture *and* haul a trailer of gravel to the construction site. Sure, all the trucks can still be used for unladen day trips, but some are more suited to that purpose and others are more suited to carrying a lot.

I really should expand on the differences between my touring/rando bike, the Sherpa, and the Nomad in a separate post, but I think I can make a quick, graphic comparison here (hoping the formatting holds; depends on resolution):

                                    Comfort/usability range by load (light to heavy):

LIGHT------------------------------------------------------->HEAVY
                                               ||||||||
Rando bike |-----------------------------|
                                               ||||||||
Sherpa Mk2               |-----------------------------|
                                               ||||||||
Nomad Mk2                                |-----------------------------|
                                               ||||||||

The bikes all overlap in load capacity, function, and general comfort/usability within the common range illustrated by the red vertical hashes. It is just that each bike has better load capability beyond (to the right) of the load range. Their relative "comfort bands" when riding unladen are to the left of the red-hashed overlaps. I think the overlap might also be a good way to assess the "all-'roundedness" of the bikes, depending on intended use.

What I hope the scale indicates is, while each of the three bikes comprise nice all-'rounders, some are more comfortable unladen and will accommodate smaller loads and others are more comfortable loaded and will also accommodate larger loads.

Hmm. I think it is too much and perhaps a bit misleading to compare all three bikes at once where overlap in function, purpose, and comfort is concerned. Here is how I would compare my rando bike to the Sherpa Mk2:

Rando bike |-----------------------------|
                               ||||||||||||||||||||
Sherpa Mk2               |-----------------------------|


...and the Sherpa Mk2 to the Nomad Mk2:

Sherpa Mk2               |-----------------------------|
                                               |||||||||||||||||||
Nomad Mk2                                |-----------------------------|

And now, for maximum contrast, my rando bike compared to the Nomad Mk2:

Rando bike |-----------------------------|
                                               ||||||||
Nomad Mk2                                |-----------------------------|

For example...

= My rando bike (very akin to a club Tour) is a great all-'rounder that excels at unladen riding and does fine with a modest load (fine with about 40lb/18kg).

= My Sherpa was also a good all-rounder, but at a higher weight rating. It rode a bit less comfortably unladen than my rando bike, but had a greater load capacity, being ideal with, say, 65-80lb/29-36kg (before it developed problems for me).

= The Nomad is also usable as an all-'rounder (I had no problem doing 111 miles on it unladen the other day, about a third of it on logging roads and really rough tracks), but it is more comfortable and really excels hauling loads as an expedition touring bike, say around and over 100lb/45kg.

Because the Nomad has a more robust frame that is less resiliant and shock absorbing when ridden unladen, it is more dependent on tire pressure for ride comfort, just as Andy Blance has taken care to note in the brochures. I made the mistake of leaving the tires at Andy's loaded maximums (45/51psi or 3.1-3.5bar) for that unladen trip, and the ride was really rough. Dropping 5-10psi or .3-.7bar does wonders to make the frame feel more comfortable when ridden without a load. No complaints, I just got distracted on departure and forgot to check and adjust after the previous day's test rides with a full load.

Quote
I would hazard a guess that strong and therefore rigid heavy touring components eliminate resilience and "give" found in lighter parts.

'Couldn't agree more!

All the best,

Dan.
« Last Edit: September 24, 2012, 03:43:59 am by Danneaux »

triaesthete

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #6 on: September 23, 2012, 11:22:40 pm »
Hey Dan the praise will go to my head, thanks, but seriously your graphic representation could (should?) be adapted for the Thorn model overview as it clearly illustrates the comfort/payload compromise. I've not ridden a Nomad but at the other end of the spectrum the RST and Audax mk3 would certainly be positioned well to the left. Some may say it's cheeky to compare Thorn's to pick up trucks  ;D

Back on topic I see Buzz-kills are derived from bow technology. Shurelee a bow stores a huge force and releases it very suddenly with a bit of recoil thrown in for good measure?? Road buzz is a low magnitude high frequency thing??
They are also mentioned as being on "Tour" (de France?) bikes but these are now subject to minimum weight limits by the UCI and could possibly use a little ballast as the regular parts are getting so light. What better than if it could be marketed as well. Mind you pro bikes are of ultra light, rigid  and thin wall construction so they could be a bit more vibe prone than most.

Taking cynical head off now
Ian

JWestland

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #7 on: September 24, 2012, 10:33:24 am »
Chipseal can only be described in expletives...my wrists nearly came off after 30 miles on that crud on the Thorn XTC and he has gel padding, cork tape and all the other works.

If there's an easy way to get rid of the vibration is causes I'd be all for it :D
Time to read some reviews on the Buzz Kill...and she how it works on steel frames with alu drops.
Pedal to the metal! Wind, rain, hills, braking power permitting ;)

Andre Jute

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Re: Anyone using/tried Bontrager Buzz-kill harmonic dampers?
« Reply #8 on: September 24, 2012, 03:16:35 pm »
A lot of handlebar vibration-dampening results from the tires used and the pressures they run for a given cross-section. If we could all just get with the plan and follow Andre's lead, we'd have it made. He's just that little enlightened bit ahead of us all with his balloon tires. Next time a very distinguished-looking gentleman passes me on his bicycle -- especially downhill at crazy-steep lean angles -- I'm looking twice to make sure isn't Andre!

I wrote something for this thread earlier but it sounded a bit smug, so I trashed it, partly on the ground that, if I can't remember when I last had pins and needles in my hands from rough roads, I don't have too much business in a thread about harmonic dampers for handlebars, though I wondered, as Dan did, if the Buzz Kills is big enough and whether adjustment would not be essential to make them work at all well. Here in Ireland we have the same problem as a Dan and Ian describe with cheap roadbuilding methods -- some of my lanes recently resurfaced have become unpleasant to ride, even with balloons, and I'm not talking about Jawine's thirty miles, just a handful of miles for instance on one circuit, which we now no longer ride because of it. I doubt those Buzz Kills would fix it.

In my days in automobiles, my special interest was the chassis and the terribly non-linear effects of the tyres at the limit. I would add to the analyses above that over vibration-prone roads in the chip seal frequency range, you can have either lightweight components with built-in damping by the qualities of the material (carbon fibre, well-proportioned steel rather than aluminium, and so on) or good solid components (which have their own resistance to high frequency vibration by their mass and material choice -- here ali is very good choice when combined with steel tubes!). Even as an old racer, I prefer the second one. I'm just not a fan of the Lotus light'n'fragile religion, though it may appear so when I express a preference for long suspension travel, firmly damped.

Some small bicycle-specific points might be of interest. I wondered if my Brooks saddle, B73 with a coil spring at each corner, doesn't aid the hands. A cyclist's bum is a pretty conductive medium, and the muscles connected to his arms start just above the coccyx and run up to the shoulders and thence to the hands, which is why so much backpain can be fixed by providing supports for the forearms in chairs, on bikes, etc.

The other surprising thing, which I discovered before I went onto balloons (which do everything Dan suspects), when I still rode on on hard, harsh, knobbly high pressure 38mm Marathon Plus (yes, I know, by comparison to a 19mm tyre with double the pressure, Marathon Plus are the lap of luxury, but the comparison is with the biggest of the Big Apples, and the most forgiving of those, the unwired folding Liteskins at that), was that the Brooks leather handgrips, which I bought for aesthetic purposes and because SJS had them on sale, offer an added margin of damping even at the high stage to which my bike (which was designed from the ground up around its suspension) is developed. More about the Brooks leather grips at http://www.thorncycles.co.uk/forums/index.php?topic=4723.0.

Andre Jute