Bar weight myth

Discussion in 'The Perfect Line and Other Riding Myths' started by Colorado_Rider, Jan 31, 2014.

  1. k-moe

    k-moe Long timer

    Joined:
    Jun 27, 2012
    Oddometer:
    4,239
    One does this by changing the mass of the bars (adding weight). More mass absorbs more energy, causing the resonant frequency of the assembly to change. This is not some BS, it's physics...the same sort of science that explains how internal combustion engines work, and allows manufacturers to make shit for us to buy :deal
    #21
  2. FrogAndTrumpet

    FrogAndTrumpet Adventurer

    Joined:
    Jan 6, 2014
    Oddometer:
    82
    Location:
    Don't ask me, I'm lost too!
    :D

    Actually the engine runs pretty smooth (I mean it's only got 26,000-odd km on the clock; bear in mind this is a 2002 bike), although I might soon update the fuelling map and make sure the throttle bodies are perfectly balanced.
    #22
  3. tvpierce

    tvpierce Been here awhile

    Joined:
    Sep 5, 2011
    Oddometer:
    547
    Location:
    Maine
    Umm... I think this explains it: :deal

    Just sayin'!
    #23
  4. Colorado_Rider

    Colorado_Rider Banned

    Joined:
    Mar 13, 2013
    Oddometer:
    1,193
    Location:
    Failville, CO
    It's not BS but for this particular application more mass is not always better. It's not about absorbing energy, it's about matching (or cancelling) the vibration to the bars generated by the engine. I've added weight to 3 different bikes, never helped a thing, Taken weight off 2, made all the difference.

    I wasn't trying to preach any facts, just put it out there, markk.
    #24
  5. k-moe

    k-moe Long timer

    Joined:
    Jun 27, 2012
    Oddometer:
    4,239
    In that case, a more appropriate thread title would be helpful. How about: "Does Adding Weight Always Reduce Vibration in Handlebars?"
    The title, "Bar Weight Myth" implies that added mass has no effect on vibration. The implication was reinforced with your first post, where you stated that, in your experience, removing weight is better than increasing it.
    #25
  6. AKDuc

    AKDuc Alaska Born Ducatisti

    Joined:
    Apr 20, 2006
    Oddometer:
    6,762
    Location:
    Anchorage, Alaska
    For me it's at least 5, most with after-market bars and all with engine/exhaust mods.

    Those bikes include a '07 KLR with Moose Racing bars w/o any guards, '05 Ducati Monster S4R w/trimmed stock bars, and the following 3 bikes with the Heli brand bars: '98 Ducati 748, '00 Ducati 996, and a '05 Triumph Daytona 955. They've all been buzz free thru the entire rpm range for many years/miles. :D

    Have fun, Mark H.
    #26
  7. hippiebrian

    hippiebrian Long timer

    Joined:
    Jun 29, 2012
    Oddometer:
    4,693
    Location:
    Long Beach, Ca.
    What is the horsepower of your bike? And how much do the bar ends weigh? Can you really feel the power difference enough to remove them?

    Sounds like nothing but bench racing "I've dropped more grams than you" thinking rather than any kind of real world power/weight ratio difference. Heck, I lose more bike weight when I take a dump than I would with removing bar end weights.
    #27
  8. k-moe

    k-moe Long timer

    Joined:
    Jun 27, 2012
    Oddometer:
    4,239
    That is nothing like what the OP is claiming. He's after comfort, not weight loss.
    #28
  9. DAKEZ

    DAKEZ Long timer

    Joined:
    Mar 18, 2007
    Oddometer:
    19,778
    Location:
    Begin Op Zoom
    Bar end weight has worked well for me on several different Thumpers. Suzuki, BMW, Yamaha, Honda. I will sometimes do 500/600 mile days on them to get to where I am going so NOT being "vibey" is important to me.

    I think I'll stick with them as they work. :ricky
    #29
  10. docwyte

    docwyte Long timer

    Joined:
    Dec 23, 2012
    Oddometer:
    1,540
    Location:
    Denver, CO
    Bar end weights and anti vibe inserts made a huge difference on my KTM 640 Adv.
    #30
  11. hippiebrian

    hippiebrian Long timer

    Joined:
    Jun 29, 2012
    Oddometer:
    4,693
    Location:
    Long Beach, Ca.
    I see. I misunderstood his statement on lightening his bars. I never heard of lightening bars to reduce vibrations. Interesting, however I've never had a problem with the weights in, so I'd never think to remove them.
    #31
  12. jmq3rd

    jmq3rd .

    Joined:
    Apr 9, 2007
    Oddometer:
    361
    Location:
    Texas, USA
    Like somebody else said, bar end weights don't eliminate vibrations, they just change them to a higher or lower frequency, and also change what RPM range they are most noticeable at.

    People are sensitive to different kinds of vibrations - so even though the bar end weights may work perfectly for most riders to reduce the discomfort caused by vibration, they may not make any difference to some riders who just don't notice the vibration in the first place. And then there are those who will find the "modified" vibrations provided by the bar end weights to be MORE uncomfortable than the vibrations without them.

    'Tis not the science of cylindrical shapes which can be propelled through the atmosphere by a combustible fuel.
    #32
  13. erkmania

    erkmania Last of the red hot left pipers

    Joined:
    Mar 19, 2004
    Oddometer:
    1,168
    Location:
    San Diego, CA
    Interesting. I also thought that the bar weights were meant to change how a wobbling front end behaves. I understood more weight would reduce the frequency so the bars didn't become an uncontrollable blur.
    #33
  14. SgtDuster

    SgtDuster Long timer

    Joined:
    Feb 23, 2010
    Oddometer:
    3,785
    Location:
    Province of Quebec!
    Funny, I was about to say the same thing about you...

    Sorry but YOU are not the "audience". Maybe part of it but it's not because you can't understand simple "science" (well vulgarized by the way) that we can't understand it ourselves. I honestly am pretty sure it wasn't useless at all and highly "digestible" by a lot of forum members.
    #34
  15. Luke

    Luke GPoET&P

    Joined:
    Aug 25, 2004
    Oddometer:
    4,488
    Location:
    Beaverton, OR
    I've got a pound of lead on each end of my 640's bars. It makes the vibes a bit worse at idle but they vanish above 3k.

    So to answer the OP, whether you want more or less weight is going to depend on the bike and probably a bunch of other things like the kind of bars, bar mounts, etc.
    #35
  16. Luke

    Luke GPoET&P

    Joined:
    Aug 25, 2004
    Oddometer:
    4,488
    Location:
    Beaverton, OR

    To change the resonance point, change either the mass of the bars or their stiffness. The easiest way to reduce the stiffness is to add rubber mounting.

    See the section on mass-spring-damper in this article:
    http://en.wikipedia.org/wiki/Damping

    Increasing the mass reduces the natural frequency (aka reasonant frequency) however it also reduces the damping factor so you end up increasing the vibrations at the natural frequency.

    To make the handlebars smoother, first try to make sure that the natural frequency of the bars isn't the same as the frequency of engine vibrations. Failing that, try to make the damping factor high so you don't get really bad vibrations at that natural frequency.

    Explained another way:
    [​IMG]
    you want to be at either the right or the left of these curves. Failing that, you want to be on one of the lower curves rather than a higher one.
    #36
  17. joexr

    joexr Banned

    Joined:
    Jan 4, 2011
    Oddometer:
    5,022
    Is that your professional opinion?:jump
    #37
  18. markk53

    markk53 jack of all trades...

    Joined:
    Dec 20, 2007
    Oddometer:
    11,511
    Location:
    Delaware Ohio

    So, what is true for 5 is true for all and makes all BS? Not getting it. Seems a manufacturer wouldn't bother if they didn't find use in it, since it does cost more.

    I will not disagree with your results though for your situations. But again 5 for you makes it universally true? If that's the case I'm thinking anything more than an SR500 is a waste since I've had a couple and find them sufficient... lame (started as a typo, but made a lot of sense) logic.:lol3
    #38
  19. bikeridermark

    bikeridermark Long timer

    Joined:
    Nov 22, 2008
    Oddometer:
    2,943
    Location:
    Southern Ohio
    He doesn't scuff his new tires in either. :evil


    I rode a friend's Versys recently without the bar ends on. WOW! It was bad.
    Every bike, every state of tune can make a difference.
    That's my professional opinion, BTW.
    #39
  20. erkmania

    erkmania Last of the red hot left pipers

    Joined:
    Mar 19, 2004
    Oddometer:
    1,168
    Location:
    San Diego, CA
    You're attention is flattering. :knary
    #40