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Shock mounting stuff

Discussion in 'Downhill & Freeride' started by Sandwich, Dec 30, 2012.

  1. Sandwich

    Sandwich Pig my fish!
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    Need new shock mounting hardware. Picked up a nice Avy shock for my project bike but guess what...shock hardware isn't the same as the Fox that came off.

    On the fox, I measured 52mm wide on the lower pin and mount, and 34mm wide on the upper mount. My calipers do not have a digital display, so I'm going by the nearest mm. Avy lists 33.65 and 51.9mm as the nearest fits. Are those correct?

    For the other frame that I'm building up, I measure 43mm on the mounts (i don't have hardware for it). The nearest fit I can find for Fox is 43.69mm, (Link). The next step appears to be either 42.16 or 44.86 (list). Will those most likely fit? Pricepoint doesn't have the ones I need...but cambria does.

    For the Avy, I'll probably grab a pair of the offset mounts here since they're the same price as Avy mounts and they'll allow me to further tweak the geometry of the frame (including leave it alone). Anybody have input on those?
     

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  2. Verskis

    Verskis Monkey

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    Not exactly helping on your problem, but on most analog calipers you are able to measure with an accuracy of 0.1mm at least. Do you know how to read the scale? This might help you: http://en.wikipedia.org/wiki/Vernier_scale
     
  3. Sandwich

    Sandwich Pig my fish!
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    Yes, mine are ****ty and are supposed to be digital but they have no battery. The markings are only by mm increments.

    Also, can the offset bushings be run in "normal" position, ie sideways, so the angles are not affected? I'm already short shocking the bike, I don't want to go too crazy yet.
     
  4. HAB

    HAB Chelsea from Seattle

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    No it'll catch fire.


    Serious answer, it'll tweak the leverage ratios a tiny bit but the difference should be pretty minor (semi-dependent on the bike in question). Hell, you could even run them backwards to partially counteract the short shocking if you decide you're not into the full retard moar slacker thing.
     
  5. Sandwich

    Sandwich Pig my fish!
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    I'm pretty full retard here. I measured the ha at 68.5* before any mods. -2 in a headset, minus one or so in a quarter inch shorter shock, maybe one more in an 8" fork vs the seven I have now. Getting these reducers might allow me to keep the leaky monster and save monay. I'm thinking rotating both in the same direction shouldn't tweak leverage but may cause rubbin issues.
     
  6. HAB

    HAB Chelsea from Seattle

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    It'll still change things a little but in that case the difference will be really minor. Not worth worrying about.
     
  7. Steve M

    Steve M Turbo Monkey

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    They won't stay in place if you rotate them 90 degrees, they'll work their way around to the slackest setting over time. Even at 180 degrees (steeper offset rather than slacker) they will eventually rotate.
     
  8. rosenamedpoop

    rosenamedpoop Turbo Monkey

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    If you want to simulate stock hardware spacing, run 1 offset facing the shock & the other facing away. Cycle suspension & determine which end rotates less as you do. Face the lesser rotating end's hardware toward the shock.
     
  9. ChrisRobin

    ChrisRobin Turbo Monkey

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    I have a set of those for my Scott Ransom... work well. I only put them on the end where there the shock mount doesn't pivot (otherwise they'll most likely rotate in the eyelet under load). What you could do is with a dremel and cutting wheel make shallow criss-crossing lines across the surface of the reducer. That way the swingarm, or linkage can have something to 'bite' on and reduce the chance of rotating the reducer.
     
    #9 -   Dec 31, 2012
    Last edited: Dec 31, 2012
  10. Sandwich

    Sandwich Pig my fish!
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    Hmmm...alright. Those are some great ideas. It's a shame the factory pins cost the same, as I'm pretty sure short-shocking will give me the angles I'm after...plus the shock should be a pretty big improvement in itself.
     
  11. Sandwich

    Sandwich Pig my fish!
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    Ok, bumpage.

    i need your helps. I think I already know, but I'm back and forth.

    I need to finalize my order for reducer bushings for the avalanche.

    I measured the old shock reducers (with shock) at about 33.8mm. I measured the frame at 33.15, but it's difficult to get all up in there. Avalanche has shock bushings at 33.65, and FOX sells 33.83 and 33.68. The 33.68mm size is significantly more common than the 33.83 size (by like 50 or so bikes that use it).

    Mine are being custom made (went with offsets), so I can get any size I want. I can remeasure the frame tonight to be sure, but is there any reason not to go for the larger (33.83) bushings, then file away any paint or extra bushing material to make it fit? I mean 0.15mm is a fart in the wind, right?

    I just don't want to order the small size and find out there's a bit of a gap. The frame in that area is plate metal, not machined linkage, so it will probably easily compress a bit. I'm not sure it's worth worrying about, but if I'm having them custom made by a guy in poland with no reference material...I need to do my measurements right.

    edit: nevermind, I went with the .68. Half of .15mm is 0.07 on each side. Not worth worrying about.
     
    #11 -   Jan 24, 2013
    Last edited: Jan 24, 2013
  12. mtg

    mtg Green with Envy

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    ^^ You're on the right track. If you're willing to put in the time (~10 minutes), you can order them a touch wide and file to fit if necessary. I'd recommend filing the hardware, not the frame, if possible.

    As far as gaps, though, the hardware is generally a little narrower than the frame, nominally. For example, for the 22.1mm wide hardware, the frame is likely to be around 22.2mm. A little bit of a gap is required to get the shock in there without excessive effort.

    And, the Proshox bushings are quality. I have one on my bike now, experimenting with geo. It's currently in the "steeper" configuration with 2mm of offset. Like Steve said above, it's an "unstable" configuration as the shock loads try to rotate it towards the slack config. I've checked mine a couple times, and as long as the shock bolt is tight, it hasn't moved yet after a handful of rides. Rotating 90 degrees probably wouldn't stay put for long, though. But, for your application (ie slacker setup), as long as you have clearance, go for it.
     
  13. Sandwich

    Sandwich Pig my fish!
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    Yeah, I decided to go with the narrower ones as I couldn't get a good measure on the original bushings, since they were on another bike, and measuring the frame gave me a lot of grief. I measured something like 33.15 on the frame, but the reducers were wider. Either it spreads or I'm just not getting an accurate read...and yes, I changed calipers.

    Also, I found a FOX "cheatsheet" that has listings for most shocks and frames. On there, most everything before 2010 with a DHX had 33.68 reducers, and everything after had an RC4 and 33.83mm reducers, so I figured on my 2004/5 frame with a DHX, I probably had the 33.68s.

    Derek from Proshox said he couldn't do any more than 0.9mm of offset on an avy reducer, since the eyelet is narrower than a fox shock. That's fine with me, as I don't want to go too extreme, but the cost of offset is $5 more, and it's still $15 less than avalanche factory stuff....it's just that the custom jam is tripping me up.
     
  14. allen

    allen Chimp

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    If you do get everything together and you end up a little loose you can always get some shims from McMaster to close up the gap.

    Al
     
  15. Sandwich

    Sandwich Pig my fish!
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    yeah i'd really like to avoid those. I know it's possible, but being able to remove your shock in one piece is great.

    I remeasured the frame last night, and came up with ~33.8. So, I must have been smoking crack, and 33.65 is the right size.