The Albatross: 1150GS Sidecar Build

Discussion in 'Hacks' started by PowderMonkey, Jun 2, 2018.

  1. PowderMonkey

    PowderMonkey Been here awhile

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    Merry Christmas!

    I decided to put both of them on there, and see which I liked better. I figure, I can run an adjustable strut in place of the linear actuator, if I decide the sway bar is more useful. If I like the sidecar tilt better, I’ll just leave the sway bar disconnected.
    #81
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  2. PowderMonkey

    PowderMonkey Been here awhile

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    IMG_3819.jpg IMG_3820.jpg IMG_3821.jpg
    Had to see the rolling chassis! She’s on the ground for the first time.
    #82
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  3. steam powered

    steam powered just a regular punk

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    I am not sure that equal sway bar lengths is appropriate here. I would think it would be more important to have each end of the sway bar travel through the same angle of movement so that one wheel doesn't exert force on the other when the shock is at full compression or extension.

    To calculate this you will need to know :
    • Rear wheel travel
    • Sidecar wheel travel
    • Rear suspension leverage ratio
    • Rear wheel sway bar arm length
    • Horizontal distance between sidecar swing arm pivot and sway bar pivot
    Then solve it for the Sidecar sway bar arm length and Sidecar suspension leverage ratio.

    The Rear suspension leverage ratio is the (Swingarm pivot to axle length/ swingarm pivot to sway bar connection length)

    So the (Rear wheel travel / (Rear suspension leverage X Rear sway bar arm)) must equal (Sidecar wheel travel / (Sidecar suspension leverage X sidecar sway bar arm))

    The rear suspension leverage will be fixed by the mount you are going to use on the bike so easiest to solve for the position to mount the sway bar to the sidecar suspension.

    So (Sidecar suspension leverage X sidecar sway bar arm length) equals (Sidecar wheel travel X Rear suspension leverage X Rear sway bar arm) / (Rear wheel travel), lets call this number A

    Now the sidecar suspension leverage equals (sidecar swingarm length / swingarm pivot to sway bar mount length)

    So A = (sidecar sway bar arm length X sidecar swingarm length) / swingarm pivot to sway bar mount length

    We also know that the Horizontal distance between sidecar swing arm pivot and sway bar pivot has to equal (sidecar sway bar arm length + swingarm pivot to sway bar mount length)

    We now have two simultaneous equations we can solve. So solving for the swingarm pivot to sway bar mount length. Not showing my workings ...

    The swingarm pivot to sway bar mount length = (Horizontal distance between sidecar swing arm pivot and sway bar pivot X sidecar swingarm length) / ( A + sidecar swingarm length)

    And the sidecar sway bar arm length = Horizontal distance between sidecar swing arm pivot and sway bar pivot - swingarm pivot to sway bar mount length

    I hope this makes sense
    #83
  4. PowderMonkey

    PowderMonkey Been here awhile

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    Thanks so much for posting this. I’m going to need to read this over more than a few more times. I totally understand that there has to be an enormous amount of math involved here, but seeing what I have to work with, it really seems as I only have a few different options for mounting location and length. I’m gonna need to do some more mock up and see where I fall within these formulae.
    #84
  5. PowderMonkey

    PowderMonkey Been here awhile

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    Threw the body on there, because I couldn’t resist. IMG_3825.jpg
    I double checked my measurements for initial setup. I’m still around 12” on the sidecar lead, rocking a 49.5” track width (tire center to tire center), and about 1” of toe in (good enough for mock-up). Sidecar is level side to side, and a bit proud in up front, so that the body can be level. From here, I’ll bubble level the sway bar etc. IMG_3830.jpg IMG_3831.jpg IMG_3832.jpg
    #85
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  6. FR700

    FR700 Heckler ™©®℗

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    Tape on the nose of the chair. Are you going to add an externally opening glovebox?
    #86
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  7. FLYING EYEBALL

    FLYING EYEBALL out of step

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    Is the Dolly in the Chair for 'top ramen' deliveries?

    looks nice!
    #87
  8. Bobmws

    Bobmws Curmudgeon At Large

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    I had that conversation with Claude. I can't speak to offroad travel, but changing from 2 lane pavement to interstate pavement I usually had to adjust the electric lift which would preload the sway bar.
    That ended my interest in adding the bar. Oh, that and the $$.....
    #88
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  9. davebig

    davebig Another Angry Hun !

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    Damn Christmas morning and I have a headache :lol3 It seldom works out that the swaybar arms are equal length , its a sidecar not a trike. Claude builds in about 3.5 to 4" travel in his swing arms they seldom ever move more than 2.5" the more you twist the bar the stiffer it gets.
    His bars are 3/4" chromoly but uses old race car ends for easier hookup and then you can vary the length of the 3/4" bar shorter is stiffer longer allows more twish and is softer.
    In a fit of not paying attention riding with passengers in a motorcycle enduro, I area tore the top on my suspension rocker mount off I drove 40 miles home with only the swaybar for sidecar suspension with passengers Justin and Mary.
    The trouble with too many things to change is everything changes swaybar preload. For best ride quality and swaybar benefits its best to insure the bar has no preload before getting on the tug , riders weight will then add preload too bar (being careful to remember it's a spring).
    One can load it up and it will handle like a sports car but it will ride like one also.
    #89
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  10. PowderMonkey

    PowderMonkey Been here awhile

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    Thanks for the first hand account, Dave!
    #90
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  11. PowderMonkey

    PowderMonkey Been here awhile

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    Took the rig for a ride last night. Felt good. Felt like a rocket ship compared to the Ural. Suspension is seriously soft. Someone, and I can’t remember whom, had suggested I send the stock shocks somewhere to have weight appropriate springs. Suspension suggestions all? What do you run, and how do you like it.

    I’m headed back to work for a few weeks, but I think I’ve got a working mock up of the sway bar. It will be very adjustable. I hope my sidecar wheel lead is close, otherwise I’ll be fabricating more than one sway bar arm.
    #91
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  12. FLYING EYEBALL

    FLYING EYEBALL out of step

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  13. PowderMonkey

    PowderMonkey Been here awhile

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    I poured back through some emails; EPM Performance was recommended by @davebig.
    #93
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  14. DRONE

    DRONE Dog Chauffeur

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    I'm sure I've recommended them in at least a half dozen threads. Klaus is the man!
    #94
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  15. REBORN

    REBORN Adventurer

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    image.jpeg image.jpeg image.jpeg Very helpful reading since I have similar project 1100GS joined with Beamer frame , fabricating my own tub
    #95
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  16. PowderMonkey

    PowderMonkey Been here awhile

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    Very cool!
    #96
  17. davet2

    davet2 Been here awhile Supporter

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    good dog
    #97
  18. High Octane

    High Octane Long timer Supporter

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  19. brstar

    brstar Long timer

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    #99
  20. arbalest

    arbalest Long timer

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    Seth,

    Just a thought. Should you have built the subframe so that it is level when the rig is laden?

    Mike