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  1. #1
    phoward
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    Marzocchi Z1 BAM (99) air assist convertion

    Hi, my current setup has a 99 Marzocchi Z1 Bam, 130mm, rebound cartridge, coil.

    My new project is to figure out if I can convert it to air assist (preload) instead of spring preload. There are two options here: keep the coils or completly remove it (100% air fork).

    I found Air CapPre for Marz 30mm stanchions cartridged fork.

    Any comments or experiences? I'll appreciate them,

    Thanks,

    Patrick

  2. #2
    MK_
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    Quote Originally Posted by phoward
    Hi, my current setup has a 99 Marzocchi Z1 Bam, 130mm, rebound cartridge, coil.

    My new project is to figure out if I can convert it to air assist (preload) instead of spring preload. There are two options here: keep the coils or completly remove it (100% air fork).

    I found Air CapPre for Marz 30mm stanchions cartridged fork.

    Any comments or experiences? I'll appreciate them,

    Thanks,

    Patrick
    Is that fork equipped with a negative spring? I don't recall it being so. Without a negative spring an all air conversion will have poor small bump compliance. Doing an air assist with one coil will probably work better. How much weight will you be saving? Is it worth the trouble and a worse riding fork?

    _MK
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    "No man goes before his time -- unless the boss leaves early."
    -- Marx, Groucho

  3. #3
    phoward
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    Thanks for the reply,

    Yes, the fork has two neg springs and two compression spring (long). I don't want to take out the neg spring, just be able to do an infinite adjust to firmness and progressitive (oil heigh).

    The paths are:
    1. Going to air assit instead of spring preload (4 spring on)
    2. Use the air assist cap to fill air necesary to take the positive springs out (only neg spring on)

    phoward

  4. #4
    MK_
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    Quote Originally Posted by phoward
    Thanks for the reply,

    Yes, the fork has two neg springs and two compression spring (long). I don't want to take out the neg spring, just be able to do an infinite adjust to firmness and progressitive (oil heigh).

    The paths are:
    1. Going to air assit instead of spring preload (4 spring on)
    2. Use the air assist cap to fill air necesary to take the positive springs out (only neg spring on)

    phoward
    I don't think you'd gain much if you left both coils in and used air as preload. Maybe a little better bottomout resistance. I would keep one of the coils in and remove the other (positive), then use air as an air assist to the coil, much like the current Marzocchis. You'll keep much of your small bump compliance, you'll lose a bit of weight and gain a bit of bottomout resistance.

    In any event, what do you have against coil preload?

    Finally, coil springs set over time, meaning they become shorter, so without a preload cap, you quite possibly will have a loose coil, rattling around inside of your stanchion.

    _MK
    .
    "No man goes before his time -- unless the boss leaves early."
    -- Marx, Groucho

  5. #5
    phoward
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    It's nothing against preload, it is all about setting the spring rate by my own and not have to spend money in differents springs. I'm on 165lb but very aggresive all mountain riding.

    By now I'm using the stock prowind coils (K=3.2 ~ 3.6 progressive) maybe little shorter and had ordered a new set of mediums (K=3.3 linear). This spring with a propper oil lever (Rotex 7.5wt) will get the progression I need to avoid bottom out, but i don't know if i could get the correct sag.

    With this in mind, I thought i can use some air assist on both legs, leave the oil low to keep the fork linear and get the sag.

    Obviously, I like this fork so much.

    I hope you are not the guy in the photo

  6. #6
    MK_
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    Quote Originally Posted by phoward
    It's nothing against preload, it is all about setting the spring rate by my own and not have to spend money in differents springs. I'm on 165lb but very aggresive all mountain riding.

    By now I'm using the stock prowind coils (K=3.2 ~ 3.6 progressive) maybe little shorter and had ordered a new set of mediums (K=3.3 linear). This spring with a propper oil lever (Rotex 7.5wt) will get the progression I need to avoid bottom out, but i don't know if i could get the correct sag.

    With this in mind, I thought i can use some air assist on both legs, leave the oil low to keep the fork linear and get the sag.

    Obviously, I like this fork so much.

    I hope you are not the guy in the photo
    Keeping the oil low will do nothing for you in terms of getting correct sag. The fork has to be pretty close to bottomout for the air pressure to be significant enough to affect the overall spring rate.

    The more info you provide the more I am leaning towards my suggestion of you only using one coil and make the other leg air assist.

    (and no, that's not me in the photo, but thanks for the concern )

    _MK
    .
    "No man goes before his time -- unless the boss leaves early."
    -- Marx, Groucho

  7. #7
    phoward
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    Quote Originally Posted by MK_
    Keeping the oil low will do nothing for you in terms of getting correct sag. The fork has to be pretty close to bottomout for the air pressure to be significant enough to affect the overall spring rate.

    The more info you provide the more I am leaning towards my suggestion of you only using one coil and make the other leg air assist.

    (and no, that's not me in the photo, but thanks for the concern )

    _MK
    That's right, i never said lever will help sag. To get it there are two ways spring preload or air preload, it's very clear.

    The oil lever is used for progressive, ie as the fork compresses the pressure goes up helping spring to resist the force. If you raise the level you change the rate at witch pressure raise, for example in my fork with a level of 55mm i get 34psi when it is completely compressed and 37psi with 50mm.

    So, let's define the project again, 130mm fork, 2 K=3,3 spring, 2 neg springs, low oil level (to keep linear but without bottoming) and air preload (to get ~19mm sag).

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