swing-arm as leading link

Discussion in 'Hacks' started by mantree, Sep 6, 2017.

  1. kshansen

    kshansen kshansen

    Joined:
    Jan 17, 2012
    Oddometer:
    472
    Location:
    Central NY
    Guess I have just been lucky with my front end on the bike over to the left there.
    <--

    I t was built back in 1992 using 1.50 DOM 0.120 wall tubing for the down pipes and the swing arm is 1.50 DOM 0.093 wall.

    Then again I don't do any real off-road riding and not jumping moguls on a dirt bike track! It does have a bit over 100,000 miles of road miles on it.

    Now if i was building one for a bigger bike or one that would see rough road conditions on a steady basis I would be looking for something stronger like the tube-in-tube design.
    #21
  2. Rockman

    Rockman Been here awhile

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    Jan 26, 2007
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    586
    Location:
    Inverell, NSW Australia
    This one has a K100 rear swingarm mounted forward and Renault wheels all round. Worked ok
    003.JPG
    #22
  3. claude

    claude Sidecar Jockey

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    We typically use 1 1/2 x .120 wall with 1 1/4 x .120 wall DOM tubing for downtubes. Same with swingarm. We also use floating calipers although have done a couple with fixed calipers (NOT preferred) .... have run stock front tire and wheel and have converted to a car tire and wheel which typically match the rear and the sidecar if possible.
    #23
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  4. BigFatAl

    BigFatAl Been here awhile

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    Aug 24, 2016
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    685
    I know this is a trike but interesting use of a swingarm for the forks.
    [​IMG]
    [​IMG]


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    #24
  5. mantree

    mantree Been here awhile

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    That is interesting build overall but that's is kind of what I was thinking

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    #25
  6. BigFatAl

    BigFatAl Been here awhile

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    I like using a fat sport bike type swing arm so you can run a rear wheel with a car tire !!!.


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    #26
  7. mantree

    mantree Been here awhile

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    I'm kinda screwed on that front with the yamaha and the friendship 1 tires but the 17 inch rear tire from a cb750k5 is the same size as the stock front tire on the venture which is part of why I want to use a cb750 swing arm. It was recommended to me to run a rear tire backwards on the front for longer life.

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    #27
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  8. mantree

    mantree Been here awhile

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    So my factory forks are 40mm so that's 1.575 so the question is would I be better off trying to squeeze something close to 41 or dropping to a 1.5 down tube and crank it down as tight as the triple trees will go.

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    #28
  9. BigFatAl

    BigFatAl Been here awhile

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    Aug 24, 2016
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    Or buy a set of forks for your bike on eBay ( or use yours) and use the down tubes for your new leading links.


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    #29
  10. mantree

    mantree Been here awhile

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    So with this method would you suggest just welding the tube at the top and bottom drilling and rosette welding them together? Once we are to the bend do you recommend going square steel or keeping with the round tube. I was thinking of using square or rectangular steel for the swing arm if I were to make one.

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    #30
  11. claude

    claude Sidecar Jockey

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    LEADING LINK FLOATING CALIPERS.jpg
    #31
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  12. mantree

    mantree Been here awhile

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    OK my original plan was to cut the tubing and notch it then welding it together.

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    #32
  13. claude

    claude Sidecar Jockey

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    Some pictures...These are not recomendations and we didn't do any of these ...whatever you do it must be strong. Keep in mind that the fork tubes are sprung weight . so 'beef' there is not much of an issue, the strength is!! Also I feel the axle should be above the pivot point otherwise it is like pushing a wheelbarrow over a curb rather than pulling it over one when you hit a bump. View attachment 9915 [​IMG][​IMG]

    Attached Files:

    #33
  14. claude

    claude Sidecar Jockey

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    upload_2017-10-8_8-33-52.jpeg
    #34
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  15. claude

    claude Sidecar Jockey

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    Not one we did .....[​IMG]
    #35
  16. FR700

    FR700 Heckler ™©®

    Joined:
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    Location:
    Your imagination.
    Air bag?

    Scratch that. Looking again, I see it's a child's tricycle. Mea culpa :fpalm
    #36
  17. claude

    claude Sidecar Jockey

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    Poor axle clamp design...This was on a unit leading link. We redid it with a two piece block. There are other ways also but the one piece heavy wall pinch block is not a great idea as you are trying to flex a piece of heavy material to capture the axle. ugh. upload_2017-10-8_8-40-6.jpeg
    #37
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  18. claude

    claude Sidecar Jockey

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    Another one. Not good. CAUGHT BEFORE THE INEVITABLE. upload_2017-10-8_8-41-33.jpeg
    #38
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  19. claude

    claude Sidecar Jockey

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    Caution: If the fender on a leading link is mounted high above the wheel on the fork tubes this is fine. If the fender is mounted on the swingarm it is critical that the mounts be done well and can endure the vibration and stress that they will go through. More than one case of this type of fendr mount failing has been voiced. What happens? The fender can rotate forward around the axle area and then the front tire climbs up into it. All of a sudden your front end is a 'ski' of sorts and it is questionable where the lack of steering may lead you. Build it stout!!
    #39
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  20. BigFatAl

    BigFatAl Been here awhile

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    Aug 24, 2016
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    685
    One thing I really like about using a swing arm on the forks is that you can slide the axle forward and backward to fine tune the steering effect !!


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    #40