Unholy Union geometry

Discussion in 'Airheads' started by Ras Thurlo, Nov 3, 2012.

  1. Ras Thurlo

    Ras Thurlo Desert Lion

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    I have to admit that on the dirt I find the handlebars on the GS can be twitchy and when associated with road-stiff suspension a couple of times were almost torn out of my hands.

    Is this down to geometry or the fact that I ride the GS slower than my EXC and therefore lack the directional momentum when say going through mud.

    Would a steering damper help?
    #61
  2. Dmaster

    Dmaster Been here awhile

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    IMO hell yeah!
    #62
  3. Prutser

    Prutser Long timer

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    I always use the SKF seals if they have them in the size I need. They are superb !

    With the 270mm travel left after i shortened them my fork is good enough. But I just want something better.
    #63
  4. Prutser

    Prutser Long timer

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    +1
    #64
  5. Phreaky Phil

    Phreaky Phil Long timer

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    How are the new triples progressing ?:lurk
    #65
  6. Prutser

    Prutser Long timer

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    Hi Phil,

    We still need to make the drawing of the top triple, but need to find the time to do that.
    #66
  7. Ras Thurlo

    Ras Thurlo Desert Lion

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    Is the consensus view that you need a steering damper for a GS off road?

    What is the reason behind this, geometry, weight....


    Could not find historic threads that spoke about this in relation to offroad riding- I'm sure its out there somewhere deep in a fork upgrade thread
    #67
  8. Lornce

    Lornce Lost In Place

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    Can't get into this just now (I've got somewhere else I need to be!) but look forward to looking more closely at this thread as time permits.

    Tuning motorcycle geometry for specific results is a lot simpler than most realise. I believe much confusion arrises from misunderstanding about which variables affect which characteristic.

    The Short Version: Trail dimension is very important.

    Talk soon.

    :freaky
    #68
  9. Dmaster

    Dmaster Been here awhile

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    Well you don't really NEED one. I rode mine almost a year without it (I'm not even riding 1,5 year offroad now :evil) but it helped allot to hold the cow go in a (sort of) straight line.
    Especially when it gets tricky, some extra hands to hold the steer.
    And i'm not even using a "off road" damper so maybe it could be better (or maybe not, I just never tried one)

    I can't really figure out why you NEED one, i don't think there is a real reason. I don't think our bikes are more "dangerous" then similar bikes.
    But I see more and more MX and enduro bikes with steering dampers on them. It just helps you control stuff you can't do your own.
    #69
  10. Lornce

    Lornce Lost In Place

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    Don't know if it's been mentioned yet, but Tony Foale is an excellent resource if you're keen to understand motorcycle chassis and geometry design and characteristics.

    No affiliation, just glad I read it so many years ago.

    :thumb
    #70
  11. Ras Thurlo

    Ras Thurlo Desert Lion

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    I also find that there is a lot of movement on the bars compared to my EXC when the ground gets tricky

    is there a downside to having one?
    #71
  12. Ras Thurlo

    Ras Thurlo Desert Lion

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    :thumb
    #72
  13. Prutser

    Prutser Long timer

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    Yes there is a downside......They are expensive !
    #73
  14. Lornce

    Lornce Lost In Place

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    I've never felt the need for a steering damper on an airhead GS or G/S.

    Might change my mind if I built a bike with too little trail.

    :augie


    :lol3
    #74
  15. Phreaky Phil

    Phreaky Phil Long timer

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    I would like to try a steering damper in sand. And on roads that have bulldust / silt / fesh fesh holes in them. Things can get ugly real quick when the bars whip around on you :eek1
    #75
  16. Phreaky Phil

    Phreaky Phil Long timer

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    On my 1st DR650 I tried some clamps with less offset than the standard one and I gave the bike a headshake at about 100kmh. It caused a shimmy in the bars above that speed and luckily never got any worse. I changed back to stock clamps, shimmy gone.
    In theory less offset = more trail = more stable. Right ? ?
    #76
  17. Lornce

    Lornce Lost In Place

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    All other factors being equal, that is correct.

    Did you alter the ride height when you added the modded triple clamps. :dunno

    Are you absolutely certain you didn't wonk the adjustment on the steering head bearings when you fitted the non-stock triple clamps. :dunno

    fwiw, I've got a stock DR650 and it's terribly unstable on soft gravel roads.

    :dunno
    #77
  18. Phreaky Phil

    Phreaky Phil Long timer

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    Yeah, all was good with the install. No other changes other than the clamps. Ran with it for a few weeks. I tried the other clamps after riding a mates Yamaha XTZ 660. It felt way more stable in the front I have a DRZ 400 front end on my current DR which is way better than the standard front end.We rode a lot of sandy tracks on the TAT and the front still feels twitchy. We were 2 up with gear, which may not have helped.Maybe to much weight up high. I haven't ridden any sandy tracks solo.
    #78
  19. Dmaster

    Dmaster Been here awhile

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    Me nether,.. till i tried one. I just didn't believe the difference.
    So i took it off (it wasn't mine anyway)
    And from that moment i really felt it helps allot.
    Stagehand has one right?
    On a (sort of) stock geometry GS/PD he can tell you more.

    I run a DRZ front end with DRZ triples.
    More trial than stock, less stable than stock :huh.
    I don't get it either but it just is.
    Tried several things can't get it as good as stock. (raising or lowering the back and/or front)
    #79
  20. Rucksta

    Rucksta SS Blowhard

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    Try a little forward weight transfer.

    .
    #80