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  1. #1
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    Help me read this: fork air pressure

    Okay, I admit, I'm one of those guys who hardly ever touches his bike once I have it set up like I like it (probably why I SS more than ride geared). Recently had the Marz 66 serviced, and got it back and needed to do some fine tuning. Went on Marz's site to see recommended air pressure, and can't for the life of me understand how to read their damn chart. Here is the recommended pressure for the 66. I'm 175 lbs, so is the recommend pressure 25PSI?
    55 - 65 (121 - 143) 65 - 85 (143 - 187) 85 - 105 (187 - 231)
    0,00 (0,00) 0,50 (7,25) 1,00 (14,50)

    Can't figure out how to align the columns here, so the the full chart can be found here:

    http://www.marzocchi.com/Template/co...1&IdFolder=778
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  2. #2
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    the bolded numbers above are kg's and lb's respectively.....so 55kg's is 121lbs (well, 121.354)...

    the other numbers are bar and lb/in^2 (or psi) respectively.....so to read this, they use coma's instead of decimel points. the second set of numbers reads as 0,50 (7,25)....translation is .5bar or 7,25lb/in^2 (psi)


    Long story short, you are in the range that suggests your psi be 7.25.




  3. #3
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    I think (7,25) means 7.25 psi. 0,5 (shown in the same row) refers to .5 Bar which = 7.25psi. This makes no real world sense to me though. What fork runs 7psi in it???

  4. #4
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    Quote Originally Posted by Maadjurguer
    the bolded numbers above are kg's and lb's respectively.....so 55kg's is 121lbs (well, 121.354)...

    the other numbers are bar and lb/in^2 respectively.....
    Yea, that's what I assumed. I guess what's throwing me are the numbers in italic here:
    0,00 (0,00) 0,50 (7,25) 1,00 (14,50)

    So, somebody in the middle range (143-187 lbs), what's the recommened bar/PSI?
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  5. #5
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    Quote Originally Posted by eatdrinkride
    I think (7,25) means 7.25 psi. 0,5 (shown in the same row) refers to .5 Bar which = 7.25psi. This makes no real world sense to me though. What fork runs 7psi in it???
    If it makes a difference, it's a coil fork. But as I said (or implied), I'm a completely clueless when it comes to this kind of stuff.
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  6. #6
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    Well....if the psi they indicate for the range of 143-187 lbs is 7.25psi....the centerspot of that range would be 165lbs since the delta between the range is 44 (half of 44 being 22....22 + 143=165). Based on that spot and saying 165lbs is to 7.25psi....then 175lbs is to X.......do the math and you get your pressure for your weight at 175 to be 7.689

    Not sure you have a gauge that will distinguish the difference between 7.689 or even 7.25 for that matter.....if you do, I'd like to see it!

    Good luck!




  7. #7
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    On the other hand....if you treat the 7.25psi as an upper limit for the 143-187lb bracket based on the observation that the lower weight range has 0psi as it's reccomendation.....then your recommended psi would be 6.785psi.......




  8. #8
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    Quote Originally Posted by Maadjurguer
    Well....if the psi they indicate for the range of 143-187 lbs is 7.25psi....the centerspot of that range would be 165lbs since the delta between the range is 44 (half of 44 being 22....22 + 143=165). Based on that spot and saying 165lbs is to 7.25psi....then 175lbs is to X.......do the math and you get your pressure for your weight at 175 to be 7.689

    Not sure you have a gauge that will distinguish the difference between 7.689 or even 7.25 for that matter.....if you do, I'd like to see it!

    Good luck!
    Oh, okay. So, 7,25 is actually 7.25. I guess that make more sense. I was thinking 7,25 meant 7bar or 25PSI. But on my gauge, 7 bar was close to 100PSI. (I didnt't even know what bar was until I Googled it just now.)

    I'll set it at a bit over 7PSI to start.

    Stoopid Euros and their unwillingness to us things us 'Mericans can understand!
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  9. #9
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    I'd go with my 2nd reccomendation now that I've had time to mull it over....so a bit lower than 7....or 6.785




  10. #10
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    Marz forks use air preload over coil. Thus extraordinarily low air pressures.

  11. #11
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    what kind of pump do they use.....is is a special, low psi pump? I imagine at those ranges 6vs7psi.....it's hard to get dialed even with a standard shock pump.




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    Yeah, you have to use the Marz. adapter and a special low-pressure pump.

  13. #13
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    Quote Originally Posted by Blatant
    Yeah, you have to use the Marz. adapter and a special low-pressure pump.
    Hhmm, I have the adapter, but was just using the shock pump I had before I got the shock. I have it set at just below the first line, which is 10 PSI on my pump.

    Did a quick Google search for "low-pressure shock pumps." Came upon a couple:
    http://www.treefortbikes.com/product...ckMate-Hi.html
    http://www.cambriabike.com/shopexd.asp?Item=100022938

    Both appear to be similar to the one I have--even though they are adversited as low-pressure (one even says it's for Marzocchi shocks), and the guage starts at 10, and goes up in 10 PSI increments.
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  14. #14
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    Is the preload air pressure used to set sag? If so, forget the psi and just set it at around 25% sag.

  15. #15
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    actually you get a smoother butter ride if you just dial it with the spring and do not use air ( air causes stiction ).
    I like to bottem the fork out and bleed all of the air then let it up out so it actually pulls a vacuum .

    The joy of a spring fork is the nice smoothe feel , why add unnecessary stiction.

  16. #16
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    Quote Originally Posted by kelstr
    actually you get a smoother butter ride if you just dial it with the spring and do not use air ( air causes stiction ).
    I like to bottem the fork out and bleed all of the air then let it up out so it actually pulls a vacuum .

    The joy of a spring fork is the nice smoothe feel , why add unnecessary stiction.
    Actually, I think before I dropped it off, I wasn't running any air. I wouldn't put it past the LBS who did it to over fill it. Nonetheless, took it out today with very, very low pressure, and made a world of difference. I'll take all the air out this weekend, and see if it's even nicer.
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  17. #17
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    Mmmm. I really like newer Marz. forks and I know some folks (particularly lighter riders) who run them with no air. I'm about 200 pounds, and have found the fork works much better and doesn't ride so deep in its travel if I put around 7-8 psi of air in it.

  18. #18
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    Quote Originally Posted by Blatant
    Mmmm. I really like newer Marz. forks and I know some folks (particularly lighter riders) who run them with no air. I'm about 200 pounds, and have found the fork works much better and doesn't ride so deep in its travel if I put around 7-8 psi of air in it.
    You would be amazed how much better it will ride if you were to get the correct spring for you in it and leave the air out

    Marz has had this set up for along time and it was meant to be deliverd with a soft spring so the air could be used as a bandaid to move the ride height and spring load around to see what worked for the rider , --once you got that figured out you get the heavier or lighter springs as needed and no longer use the air .

    Pulling a vacuum in the air side and runing the correct spring makes a world of difference .

  19. #19
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    Quote Originally Posted by kelstr
    You would be amazed how much better it will ride if you were to get the correct spring for you in it and leave the air out

    Marz has had this set up for along time and it was meant to be deliverd with a soft spring so the air could be used as a bandaid to move the ride height and spring load around to see what worked for the rider , --once you got that figured out you get the heavier or lighter springs as needed and no longer use the air .

    Pulling a vacuum in the air side and runing the correct spring makes a world of difference .
    Do you happen to know what the recommended spring is for somebody 175? To be honest, I'm not even sure I know what spring I have in now.

    I'm going to try the vacuum trick tomorrow.
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  20. #20
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    Marz springs are not as easily/routinely accessible as, say, a RS or Fox coil. Not to mention if you happen to running the ti version, the coils are astronomical.

    Others may disagree. I find the newer generation of Marz. forks to be very nice and I really like the tune-ability of the low-pressure air preload. Inevitably with other coils, the medium is too light and the heavy is too much and you're stuck with coil preload, which IMO is more of a tradeoff than low-pressure air preload.

    ST: I'm about 20 pounds heavier and I don't like the fork without a few pounds of preload; give it a whirl, though, and see what you think.

  21. #21
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    Quote Originally Posted by Blatant
    Marz springs are not as easily/routinely accessible as, say, a RS or Fox coil. Not to mention if you happen to running the ti version, the coils are astronomical.

    Others may disagree. I find the newer generation of Marz. forks to be very nice and I really like the tune-ability of the low-pressure air preload. Inevitably with other coils, the medium is too light and the heavy is too much and you're stuck with coil preload, which IMO is more of a tradeoff than low-pressure air preload.

    ST: I'm about 20 pounds heavier and I don't like the fork without a few pounds of preload; give it a whirl, though, and see what you think.
    It was night and day from Monday's ride (probably over inflated) to last night's (about 6 PSI). I'll try no air tomorrow, just to check it out. For the most part, I've loved the fork.
    Nobody gives a s#$t you singlespeed.

  22. #22
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    Quote Originally Posted by skinny-tire
    Do you happen to know what the recommended spring is for somebody 175? To be honest, I'm not even sure I know what spring I have in now.

    I'm going to try the vacuum trick tomorrow.
    If you bought the fork or bike new the forks come with a med light spring in them generally unless you specify on of the optional springs.

    You can say that the standard spring is for a150 to 180 lbs rider, but thats just a guide line .

    You really can not go buy the book on spring rate for a givin wt rider, there is so much that goes into bike set up,frame size, riding style and how hard and fast you pound .

    I have little guys at 120 lbs that are on custom springs that are heavier that the optional heavy springs , and they run twice the valving on the damper too.

    You just test and see what feels good for you , you can raise or lower the oil height to suit dive and bottoming also as well as change the valving on the damper and spring preload as well.

    It sounds like the spring you have is close to what you will end up with .

    I have " Cannon racecraft " make the springs I need for my testing , ( the factory springs rates are to far apart and they vary in the rate they say they are , I always test the springs so I know what Im working with )

    It takes some time and testing with oil heights and damping and taking notes to figure out what your set up will be .

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