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  1. #1
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    What is the psi for the IFP of a 2011 Vivid R2C coil?

    I'm at a loss. All the service manuals refer to the older 4.1 and the 5.1s

    IFP pressure spec varies from 200-230-250.

    I just rebuilt my shock. I put 200 psi in for starters. What should it be?

  2. #2
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    earth to suspension gurus. earth to suspension gurus. failure to launch

  3. #3
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    250 psi works. That's what I ran in mine. Doesn't really matter, as long as it keeps the shock from cavitating.
    Last edited by Scotth72; 04-06-2013 at 06:55 PM. Reason: grammar

  4. #4
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    R2C - 200psi
    R2 - 230psi


    Straight from service manual
    http://cdn.sram.com/cdn/farfuture/1d...cal-manual.pdf

  5. #5
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    Quote Originally Posted by Josue View Post
    R2C - 200psi
    R2 - 230psi


    Straight from service manual
    http://cdn.sram.com/cdn/farfuture/1d...cal-manual.pdf
    I appreciate the help and I almost jumped when I saw that you found the manual.

    However, that is the Vivid Air manual. Do you think its the same for the Vivid R2C Coil?

    Not being picky, just wanna run it right. As far as the other guy saying that the IFP pressure doesnt matter, well, the IFP against shock dive and small bump sensitivity. Adjusting volume and pressure does a world of difference. However, I'd really like to set it at the baseline.

  6. #6
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    You won't feel a difference of 20-30 psi in the IFP on a shock with no position sensitive valving, and a smaller diameter shock shaft.
    The baseline is lower than I thought, its been a while since I have owned that shock. Here is the link.

    http://cdn.sram.com/cdn/farfuture/Iy...s/tm_my102.pdf. Page 149.

  7. #7
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    Quote Originally Posted by Scotth72 View Post
    You won't feel a difference of 20-30 psi in the IFP on a shock with no position sensitive valving, and a smaller diameter shock shaft.
    The baseline is lower than I thought, its been a while since I have owned that shock. Here is the link.

    http://cdn.sram.com/cdn/farfuture/Iy...s/tm_my102.pdf. Page 149.
    true. but a 50 psi diff (200-250) seems substantial. im new to this shock, i did find that manual, it is for the 4.1 and 5.1. i used the 5.1 pressure as the bleed process requires open the lsc just like my r2c, im guessing both models are pretty close.

    as an aside, i dont see any info about playing with IFP volume to tune the shock. shame.

    thanks.

  8. #8
    Vorsprung Suspension
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    Quote Originally Posted by bing! View Post
    true. but a 50 psi diff (200-250) seems substantial. im new to this shock, i did find that manual, it is for the 4.1 and 5.1. i used the 5.1 pressure as the bleed process requires open the lsc just like my r2c, im guessing both models are pretty close.

    as an aside, i dont see any info about playing with IFP volume to tune the shock. shame.

    thanks.
    IFP depth and pressure are not considered legitimate adjustments on this shock, or any shock without position sensitive valving. The IFP pressure is only there to prevent cavitation during the compression stroke, and the depth only needs to be set in such a manner that the IFP cannot bottom out if the temperature drops substantially (and the fluid contracts) and that the air pressure does not ramp up too significantly by the time the shock has bottomed out. Trying to use gas chamber volume to "tune" non-position-sensitive shocks basically results in something that will ramp up the air pressure (and therefore all pressure in the shock, and load on the seals) immensely, quite rapidly late in the stroke, for little impact on the ride quality of the shock. Better to just use the adjustments as intended, replace the dropstop as needed, or revalve as required.
    VorsprungSuspension.com - fully engineered suspension retuning & servicing in Whistler, BC.

  9. #9
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    Quote Originally Posted by Steve VS View Post
    IFP depth and pressure are not considered legitimate adjustments on this shock, or any shock without position sensitive valving. The IFP pressure is only there to prevent cavitation during the compression stroke, and the depth only needs to be set in such a manner that the IFP cannot bottom out if the temperature drops substantially (and the fluid contracts) and that the air pressure does not ramp up too significantly by the time the shock has bottomed out. Trying to use gas chamber volume to "tune" non-position-sensitive shocks basically results in something that will ramp up the air pressure (and therefore all pressure in the shock, and load on the seals) immensely, quite rapidly late in the stroke, for little impact on the ride quality of the shock. Better to just use the adjustments as intended, replace the dropstop as needed, or revalve as required.
    good to know. bleeding the shock to change the ifp volume is an involved process. it would have been a pain to go back and forth for no performance gain.

    much appreciated.

  10. #10
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    IFP Pressure are going to depend on your shocks tune. Stiffer valving needs high pressures to prevent cavitation. The range for most piggyback coil shocks is 175-250. My suggestion would be 200psi for a low compression tune, 225psi for a medium, 250psi for a high tune.

  11. #11
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    Rockshox manuals are very easy to find.

    The only thing that changes between air and coil is the spring system. The dampers are exactly the same. They are independent from the springs.

    Just check if your shock is R2C or R2 and fill the IFP chamber to the correct pressure.

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