Hyperpro fork spring install questions

Discussion in 'Parallel Universe' started by myblubeemer, Apr 7, 2010.

  1. myblubeemer

    myblubeemer MOA, IBA

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    OK, first I apologize if this has been addressed in one of the supspension threads previously. I did read a lot of them and didn't see anything on this. The Hyperpro insturctions indicated that their progressive spring should be installed with the tightly wound side up. However, when attempting to do this it becomes virtually impossible to get a 13mm wrench between the spring to tighten the jam nut against the top cap?

    Has anyone had this problem and did you just go with the porgressive or tightly wound side down?

    I drained out a little less than 600ml of fork oil from each fork. I assume I should put the same back in each? Is there a revised amount? seems like I read 520ml somewhere?

    Can you just pour the new oil in the and let it settle or do you need to work the forks to get it in the system?

    Thanks Much for any assistance.

    jwat
    #1
  2. itsatdm

    itsatdm Long timer

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    It probably doesn't make much different, one way or another. I just took a 1" wide pc of scrap steel strap, cut a V in it and slipped between the spring and the bolt on the rod.
    #2
  3. SCVGS

    SCVGS Adventurer

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    The tight side does indeed go up. you can pull the spring down by hand and just slip the wrench in onto the jam nut. Hyperpro recomends a fork oil level not an ammount and you do need to bleed the cartrige before taking the measurment. I believe they have instructions with the ammount info on their web site
    #3
  4. bxr140

    bxr140 Flame Bait

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    It has. :norton

    In a most technical sense, the tighter wound side should go up, as the instructions state. From a physical standpoint you can install them either way, and from a performance standpoint it won't be THAT much different (if its noticeable at all) if you install them upside down.

    Unless you're REALLY diligent with getting ALL of the fluid out, volume is sort of irrelevant. There is no real "right" answer for fluid volume...what is more important from a real world standpoint is the height of the oil in the forks, or more specifically the height of the air above the oil. Put in enough oil to make that gap at least 4-4.5" when the slider is all the way down (without the spring installed), but not more than about 5.5". Try to get both forks to be the same (its not a huge deal if they're different, its just easier down the road) and then write that number down. That way you have a known baseline in case you ever need to go back in there again, or in case you want to go back in there to fine tune.

    I've always worked as much air as possible out of the damper when I re-assemble a fork. If I had to guess, I'd say the air would eventually all work its way out, but I don't know how long that would take, and the damping basically wouldn't work (to one degree or another) until you get the air out. If nothing else, its easy and free peace of mind.
    #4
  5. myblubeemer

    myblubeemer MOA, IBA

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    Thanks for all the info......the HyperPro instructions were pretty generic. I'll give it a go!
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  6. The Griz

    The Griz Long timer

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    I was able to slip my Park 13mm Cone Wrench that I use for my mountain bike in there:
    [​IMG]

    You could also just pull the spring down if you don't have a cone wrench.
    #6