Swing arm angle - fitting a shorter shock

Discussion in 'Technical Help' started by pingping010101, Jun 16, 2013.

  1. Can some one help me understand the consequences of switching a rear shock for one 21mm shorter?

    Google is not being my friend this morning and I'm struggling to work it all out.

    Can the difference be countered with a longer or shorter custom linkage?

    If its not going to change much, I'll keep the linkage as it is, if it'll make a big difference I'll fabricate a new one.
     
  2. It will slow the steering quite a bit, so you will then have to push the forks through the yoke more, dropping the nose to compensate........

    AL
     
  3. Google is shit these days, it either brings up ads, ebay or youtube. Page after page after page. Beginning to think the internet is now broken
     
  4. What bike?
     
  5. what purpose?
     
  6. 21mm is a huge step change to the detriment of handling. I would fabricate a linkage and maybe add 5mm to it to perhaps aid the handling somewhat.

    Here is a pic of my setup, my shock was made by Maxton for a 748 which is some 35mm shorter than a std 620ss shock so I modified the swing arm but still retained the original position.

    Shock Mount.jpg
     
  7. 749 I would guess. Don't they have a ride height adjuster?
     
  8. Er.... It's not for a Ducati...


    I'm attempting to fit a brand new 2013 zx10r shock to a 1989 zxr400 H1 project bike but the eye to eye length is 329mm on the original and the new one is 308mm
     
  9. Long time since I had a ZXR...does it have any ride height adjustment? Otherwise looks like a Ghostie solution
     
  10. I can do something like that... So I'd need to maintain the wheel base and seat height etc by moving the pivot point forwards?

    I wasn't sure if linkages had a specific moment to cause progressive dampening or some such.

    It seems if you change one part of the geometry it changes everything else
     
  11. No, looks like I'll needto do more research
     
  12. Well Ghosties bike goes and handles well enough so maybe thats he way forward. Or you could add some high bars and make it a low ride chopper lol
     
  13. Its more of a refresh on the zxr400 concept...

    I had a letter published in superbike magazine a while ago moaning that I wanted a new 400cc inline 4 to enjoy whilst keeping my license...

    So now I'm making my own...

    H1 ZXR400 base
    AMS new style race fairing (day light use only so no lights)
    Zx10r 2013 shock
    Some new forks (I know Mark at MADASL has some Ducati forks in his lock up I need to enquire about otherwise I'll need a think about these...)
    Gsxr750 front calipers
    A custom GP style exhaust (eventually... This will be expensive)
     
  14. can the bottom or top eye of the shock be extended to the length you want with a £30 eye i know you can alter the length of a ttx with the eye
     
  15. I could definitely knock up some thing to do that.

    I was worried it would rotate around the eye and be a weak point that's liable to shear
     
  16. with ohlins you can just buy a longer eye....

    ohloins eyes.JPG

    ohloins eyes.JPG
     
  17. it also doesnt have to be a kawasaki part either .......i know with the vfr400 honda an aprilia 250 shock fitted....

    find something thats the length you want and then find a new one at the price you want...
     
  18. I picked up a brand new, removed to build a fresh race bike 2013 ZX10R shock for £57 delivered.

    If I can't make it work I doubt I'll lose money selling it on.

    Next week I'll try making a longer eye out of mild steel and if that's no good, I'll adjust the linkage.

    Thanks chaps
     
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