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  1. #1
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    50 psi in RS Revelation fork for low-weight rider?

    I weigh 130 lbs with gear and have a 2010 RS Revelation 150mm fork on my Ibis Mojo. I am running 30% sag in back (as this is a DW link bike), and some MTBR posters have suggested that I should have a similar amount of sag up front, even though the RS manual talks about 15-25% sag.

    So assuming that I want 30% sag, that's 45mm. In order to get that, MTBR posts have said that I start with the negative pressure at zero, and increase positive pressure until I get the right amount of sag. I then add negative pressure until it causes the fork to start sagging when I'm off the bike.

    Following those instructions, I have found that I get 30% sag if I have 50 psi positive and about 22 psi negative. Those numbers are much lower than RS recommendations of 90-115 psi. However, my fork feels fine on rides.

    Do my numbers make sense?

    Can I damage the fork if I have too low pressure?

    I have tried higher numbers such as 70 positive and 50 negative, but I find that while I can get 30% sag, the fork tends to sag a lot even when I'm off the bike.

    Also, I was trying to find a way to get the negative pressure close to the positive pressure so that I can have more small bump compliance, but couldn't find a winning combination.

    Thanks!
    Mark

  2. #2
    mtbr member
    Reputation: 'size's Avatar
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    Quote Originally Posted by moshemark
    I weigh 130 lbs with gear and have a 2010 RS Revelation 150mm fork on my Ibis Mojo. I am running 30% sag in back (as this is a DW link bike), and some MTBR posters have suggested that I should have a similar amount of sag up front, even though the RS manual talks about 15-25% sag.

    So assuming that I want 30% sag, that's 45mm. In order to get that, MTBR posts have said that I start with the negative pressure at zero, and increase positive pressure until I get the right amount of sag. I then add negative pressure until it causes the fork to start sagging when I'm off the bike.

    Following those instructions, I have found that I get 30% sag if I have 50 psi positive and about 22 psi negative. Those numbers are much lower than RS recommendations of 90-115 psi. However, my fork feels fine on rides.

    Do my numbers make sense?

    Can I damage the fork if I have too low pressure?

    I have tried higher numbers such as 70 positive and 50 negative, but I find that while I can get 30% sag, the fork tends to sag a lot even when I'm off the bike.

    Also, I was trying to find a way to get the negative pressure close to the positive pressure so that I can have more small bump compliance, but couldn't find a winning combination.

    Thanks!
    Mark
    in my experience RS recommendations on psi are way high. run what works for you.
    how are you measuring fork sag? sitting on the bike or standing in the 'attack' position?

  3. #3
    mtbr member
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    Mar 2007
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    how are you measuring fork sag? sitting on the bike or standing in the 'attack' position?[/QUOTE]

    Sitting. (Note: I always pedal while seated, and reserve standing only for very bumpy downhills.)

    Mark

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