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bar end weights for solid bars, how heavy?

Discussion in 'Modifications and Projects' started by oldcorollas, Feb 13, 2015.

  1. #1 oldcorollas, Feb 13, 2015
    Last edited: Feb 13, 2015
    ZZR250 has solid bars, after 3-400k's of buzzing they suck a bit.
    easy to drill and tap the bars to accept end weights but how heavy?
    aftermarket ends have anywhere from buggerall up to nearly half a kg...

    any suggestions for weights to try? (EX250R seems to be 125g, but not sure if they are hollow or solid bars)

    I know the answer is "whatever weight stops the vibrations"... but better to have a sensible starting point.
  2. What do the bars weigh ?
    The end weights I've seen seem to be similar in total weight to the bar weight.
    See what that does for you.
    • Like Like x 1
  3. shit.. I knew I should have weighed them while they were off last night :D

    22mm diameter (22.5 with paint) and say roughly 25cm long, (23+plus the end bits?), alloy
    = around 240-260grams

    so 30mm diameter ends, stainless = 56g/cm length, 250g = 4.4cm
    35mm diameter = 77g/cm, 250g = 3.2cm
    plus extra bit over end of bar (30 or 35-22 dia) about 25-30g

    thanks, seems like a good size to start with :)
  4. I think that the problem might not be with the bars themselves but with the way the bars are mounted. To stop the vibrations you may need rubber mounted bars, not bar weights. I thought that bar weights only help in reducing the speed of which the bars move back and forward because there is more mass to move. The more mass (or weight) the slower the bars move.
  5. Yes but this also translates into vibration damping as well. After all vibration is movement. As you rightly say the bar end weights damp movement. Because they are right on the end of the bars their effectiveness is increased. What you are generally trying to prevent is resonance, that is at certain speeds the vibration is in phase and builds on itself. Bar end weights will generally lower the point of resonance.
  6. just reducing the amplitude of movement would help I think, even if actual vibration frequency doesn't change.
    cruising rpm is 7-8000, so it gets "buzzy" in the bars after half a day. If I could stretch that to a full day, I'd be happy :)

    That's my understanding. either by lowering the resonant frequency enough so higher order vibrations are less of an issue, or by "pinning" the end of the bar (ie like closed end tube vs open end in acoustics?)

    I don't have the right sensors to measure the vibration, but even if I did.. not sure I could be bothered going that far and calculating stuff :p

    bar has two offset mounting bolts

    had considered clip-ons like these http://www.bikermart.co.uk/prodimages/158-xxxl.jpg
    but... it's a ZZR250... no point overinvesting in hardware ;) and no guarantee they would help
  7. You are probably just holding on too tight you know. The zzr is not that bad.
  8. was waiting for someone to say that :troll:
    there is definitely less vibration through the hands when I take them completely off the bars.... but then it gets a bit of a waggle at high speed. then I just use left hand to stabilise it ;)

    on longer rides, on straights I tend to lightly pinch throttle with thumb and forefinger, just enough to stop it rotating.
    not sure how that would be considered holding on too tight?? should I only use forefinger by itself?

    there feels like less vibration where the bars meet the triple, and a lot bigger amplitude at the ends..
    slightly loose throttle tube probably doesn't help the right hand either.
    • Funny Funny x 1
  9. drilled and tapped the bars to 8mm

    made some rough ~300g end weights to see if it would work...

    before, the vibration increased from inside to outside of bars.
    now, the vibration at the end of bars is same as at the middle of the triple, and much much more tolerable...

    or slightly boring :D

    just need to clean up corners, or add transitions.. then Loctite them in :)
    • Like Like x 2
  10. rounded the edges a bit, which knocked em down to 290grams, then painted and loctited in.
    note to self: Loctite dissolves paint if not dry...

    they work fantastically! the vibration at the end of the bars has been almost eliminated.
    you can feel the vibration go from almost nothing at end of bars, and increase toward the middle.
    still has same vibration at middle as before, but the bars are way more comfortable now!

    I did try local bike shops to get some heavy ends. was told you can't get heavier than the alloy ones, that you can't fit end weights to a ZZR (and why would you bother anyway), and that the stock ones (like Kwaka 1xxx type bikes, triumph, bmw etc) are maybe $60-80 per side..

    thought about getting HVMP, or scooter ones (they are quite heavy, 3-500g), but in the end.. these will do. and free is good value ;)

    although they do look a bit shit...

    could potentially countersink the ends, or grind more off the handlebars to get them closer to the grips.. but rather make whole new, smaller diameter ones if I'm going to put in a minute more effort ;)