Rock Shox Quadra rebuild CHEAP - done

Discussion in 'HOW TO' started by Indyjps, Jul 8, 2019.

  1. Indyjps

    Indyjps

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    I have a 94 trek 930 with rock shox quadra 10 forks, theyre dead so its been sitting for some time. My buddys teen son was looking for a trail rider to keep at their cabin. Guess what pops up, '94 trek 930. Exact match to my bike with a bit smaller frame. It was meant to be. The rock shox on the second bike have a little life but not much.
     
    Last edited: Jul 8, 2019
  2. Indyjps

    Indyjps

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    After watching videos on how to rebuild rock shox, the elastomers are what goes bad, other than corrosion and grit.

    If youre not familiar, elastomers are 3/4" urethane bar stock. After pulling one out, Its a purple floppy solid rod 6" long. Thats for quadra rock shox, judy rock shox have stacks of shorter elastomers so you can tune the ride ( different design with tubular elastomers that slide over a rod and remove as a pack). Replacement elastomers are $55. WHOA.

    I considered rigging some springs. But there no dampening, maybe a spring and rubber combo......

    I started learning about PUR polyurethane specifications.

    Screenshot_20190708-114045_Chrome.jpg

    Found this handy little chart. Shore A spec (middle) is the one we'll look at. Shore A is the closest thing to durometer I can find for this material.
     
    Last edited: Jul 8, 2019
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  3. Indyjps

    Indyjps

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    Found this on amazon. $11 for 48" of 3/4 diameter shipped to my door.
    Screenshot_20190708-203033_Chrome.jpg

    Amazon didnt know Shore A spec on the bar.
    I looked up the manufacturer, small parts inc, and by checking their manufactuer number againt some Shote A data they had. The Shore A is in the manufacturer number.
    Screenshot_20190708-203153_Chrome.jpg
     
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  4. Indyjps

    Indyjps

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    Gonna rebuild one of the rock shox with Shore A 60, PUR polyurethane bar in place of the elastomers. From the chart above, 70 is car tire rubber, 40 is pencil eraser.
    We'll see how it rides. If i dont like it I can move up or down durometer (shore A #) or cut the bar in half and go harder or softer to tune the suspension.
     
  5. RustyGold

    RustyGold

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    Definitely report back on this...I have a couple Girvin forks and Pro-flex frames that I was wanting to run elastomers on...but, I can always find something more interesting to spend $55 on than chunks of poly :grin:.

    Jason
     
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  6. HuffnPuff

    HuffnPuff

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    That's great. I rescued some Manitou 2 forks a while back and spend the $75Au to get new rubbers. If I had known this ....
     
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  7. Indyjps

    Indyjps

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    Took some digging around to find the info....and its still untested. Rock Shox was not in the new plastic development world, had to be an off the shelf item.
     
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  8. Indyjps

    Indyjps

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    Sorry about going absent. Bought a couple trucks at an asset auction, took a while to get them picked up.

    Original elastomer is purple, New is yellow. New is a little larger diameter but fits in the tube and end caps fine. Seems to be the same durometer from finger nail test and finger bend test - not real scientific.
    Original was 6 1/16, cut the new material to 6 1/4, just cause it seemed like a good idea.
    20190715_191637.jpg 20190715_191637.jpg
    20190715_191716.jpg

    I need to make a long 5mm hex extension before i can tear these down.
    Interested to see if adding length and new elastomer makes these ride well, i can always cut a 6 1/2 or 6 3/4 piece. Have plenty of material.

    I can practice on friends kids bike fork rebuild since hes about 130 lbs, see how stiff they are and adjust for my fork rebuild to carry more....um...mass.
     
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  9. RustyGold

    RustyGold

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  10. Indyjps

    Indyjps

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    20190811_164750.jpg
    Got a chance to finish this up today and ride.
    New PUR rod at 6 1/4 feels great. Took that inch or so of deadness out of the top of travel that rock shox get.
    Ill likely go 6 1/2 on mine for a little more stiffness.

    The bike itself is great, looks like all original parts, everything cleaned up and tuned up well.
    Its a bit small for me, but brought back some memories.

    Need to pull my trek 930 off the shelf and go thru it. Shox are figured out, the rest is wear.
     
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