An Unholy Union: Swing Arm modifications

Discussion in 'Airheads' started by Ras Thurlo, Sep 26, 2017.

  1. Ras Thurlo

    Ras Thurlo Desert Lion

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    So you have decided to upgrade your Airhead suspension with new forks, but what to do with your swing-arm and ride height?

    Keep your monolever stock or extend?

    Stick to your gen.1 paralever or go for an 1100 conversion?

    Its all about the 'booty on this thread
    #1
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  2. Jim Day

    Jim Day full manic mechanic

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    That awkward moment when you run out of mods. :lol3

    I'm sticking to my extended monoshocked twin arms for now. The 65mm extension has worked flawless, and I'm sure the 100mm extension twin will have similar performance. I saw a nice 3 bolt mono FD for sale the other day and did not even look twice. I'll be staying with the twin arm. I have been very tempted to try my R1100 swingarm on something, anything, but the R65 is resolved and my R100R build currently rides too nice to change so it's just collecting dust for now. :beer
    #2
  3. Ras Thurlo

    Ras Thurlo Desert Lion

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    an interesting post on the effects of swing arm extension:

    #3
  4. Magnon

    Magnon Been here awhile

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    I'm no expert but my stock R100GS suits me off road. It is something of a bulldozer compared to a modern enduro bike due to it's long wheelbase and shallow rake but for the sort of riding I do it's fine. My R80G/S, not that it's a rider yet, has got a 100mm extension as I see this as the only way to get sufficient suspension travel and I don't think the long wheelbase is going to bother me on road or off - I like old guzzis so I'm used to slow steering bikes!
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  5. Jim K in PA

    Jim K in PA Long timer

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    Twin shock or GTFO . . . :D:D
    #5
  6. Heipaal

    Heipaal Always the hard way

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    A R100GS paralever is 3cm longer then a monolever, i did a a 5cm extension by cutting up two monolevers and welding them back together:

    IMG_20170308_1715025_zpspsxfomch.jpg

    IMG_20170308_1841428_zpsf48fguy4.jpg

    IMG_20170310_1250155_zpspszrf4ln.jpg

    IMG-20170414-WA0004.jpg
    #6
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  7. Ras Thurlo

    Ras Thurlo Desert Lion

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    From memory the relative rear suspension travels:

    G/S monolever OEM (180)mm
    100GS Paralever OEM 185mm, not really improvable due to shaft angles
    G/S monolever stock length max 200-210mm
    1100 Paralever on airhead c.235mm
    Monolever +50mm extension (235)mm
    Monolever +100mm extension HPN style c.250mm
    Monolever +100mm extension TAG style c.265mm
    #7
  8. aptbldr

    aptbldr easy rider

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    What's difference between these two, besides available travel?
    #8
  9. Ras Thurlo

    Ras Thurlo Desert Lion

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    travel and ride height

    both stock length
    #9
  10. photorider

    photorider Been here awhile

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    What is involved in putting a 1100 paralever on an Airhead?
    #10
  11. elmontanero

    elmontanero Practicing...

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    I bought an extended mono years ago, driveshaft included from here. Sadly it's sittin in the shed unused. The WP50mm front end is shortened and handles so nicely right now I'm hesitant to mess with things.
    Also rumored that you've got to make room in the frame crossing for the extended to do it's things and that's just a step too far for me - need to find a donor ST or otherwise that I can mess with and return the g/s back to stock.
    #11
  12. BicyclebBob

    BicyclebBob Been here awhile

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    I have a question... will the 1100 final bolt up to an airhead paralever?
    #12
  13. Rucksta

    Rucksta SS Blowhard

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    If you're happy with 225-230mm travel on a 100mm extension the almost invisible mod to the cross member is not required.
    For max travel, heating and squashing the cross member to allow extra clearance for the mouth of the swing arm is required.

    Also required for gaining max travel is
    - removal of the extra metal where driveshaft penetrates the curve in the swing arm.
    - positioning the lower shock mount to utilise the extra angle available. (20mm on mine)
    - mods to the cush drive assembly to prevent fouling the tail of the spring against the swing arm interior.

    With the stock length swing arm and the mods above 210 mm of travel is possible but frame bracing at the swing arm pivot and top shock mount is advisable.
    #13
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  14. Ras Thurlo

    Ras Thurlo Desert Lion

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    yes and can be done with either your airhead FD or the 1100 FD

    you need one of these adaptors, and need to play with the rear wheel offset to keep wheel on the centreline - nothing particularly complicated and has been done by many

    Attached Files:

    #14
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  15. Phreaky Phil

    Phreaky Phil Long timer

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    The1100 swingarm is about 5 mm narrower than the GS one. I think the normal method is to weld a threaded piece on the inside of the frame on the left side and use a longer swingarm bolt.
    #15
  16. Phreaky Phil

    Phreaky Phil Long timer

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    Having ridden stock and extended versions, what are you thoughts of handling with a pillion. ?
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  17. Rucksta

    Rucksta SS Blowhard

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    Phil

    Haven't carried a pillion for almost 30 years.
    Last time I did the combined weight of rider and pillion was about equal to or less than my current weight.
    #17
  18. Phreaky Phil

    Phreaky Phil Long timer

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    :lol3 Fair call.
    I'm thinking that longer has to be better with a pillion, as the front ends up lighter with the weight of pillion and gear rearward.
    But 50 or 100 mm ?
    Pruster has built quite a few 50 mm ones and the consensus is that they work great. I had an email conversation with Paul Rooney a couple of months back and he said he used to do quite a few 50 mm ones but a lot who had them tried the 100 mm and changed to that.
    Or keep it short and sweet !
    #18
  19. Ras Thurlo

    Ras Thurlo Desert Lion

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    I have a paralever, a stock length mono adjusted for more suspension travel and a +100mm mono.

    IMHO:

    A stock length monolever with extended travel is a great bike that can do everything. The "flickability" on the road is great and it will cope with everything enduro that a 200kg bike can handle. But its clearly not as plush as the +100.

    The +100 is my favourite bike for my favourite type of riding. Its a supa-plush ride and I like to call it a magic-carpet. I understand why the Australian Rooney crew ultimately go for this, as for a trans-Australian red-dirt fest I can't think of anything better. If every ride were a dirt ride on this bike, I would be a happy guy.

    Downsides are that its tall, which limits its practicality as a daily commuter. And is less nimble. I don't mind this on dirt as I dig the long-board stability but on the hilly twisty roads I get at home you have more fun with the stock length.

    I am converting the paralever to a +50mm mono as I don't like the paralever offroad. It is really smooth on tarmac but in the dirt the rear feels like a bucking horse in comparison to monolevers. It is as if the unsprung weight is materially greater, although the difference is actually not so big. I suspect the torque arm creates resistance and works against the free movement. However there are others with more paralever experience/knowledge than me.

    Prutser has a +50mm which he seems to use all the time, and i suspect that it is the best 360 option. Will let you know how it goes.

    Obviously all this depends on road/dirt ratio (actual ride time but also which is your primary focus) and rider height.

    In conclusion: If wanted a roadster then a paralever is great, although some prefer the monolever for its nimbleness. A stock mono with extended travel if you want more than 50% road focus, the +100 mono is a no compromise beast, while I suspect/hope the +50 will be the best all-round for someone like me that prefers the dirt.
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  20. Prutser

    Prutser Long timer

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    For two up the plus 100 will be the best option IMHO. It's hard to get all the luggage and rider weight between the wheels with the stock length or even the plus 50mm mono. So the longer swingarm will help
    I love my plus 50mm ST but I notice I use my stock length R65GS a lot because it feels so nimble and light.

    I think Ras described everything really well.
    #20
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