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  1. #1
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    Spring rate for DHX coil?

    Long time lurker here, and I'm currently building up my first knolly.

    I picked up a used DHX5 coil, anyone know what spring rate I need for my Chilli? I'm 190 lbs. My Turner uses a different length spring, so I have to guess at what spring to buy.

    Thanks.
    Taiwan could probably TIG weld a ham sandwich to a dictionary these days, but its been a while since they were doing brazing.

  2. #2
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    Quote Originally Posted by AndrewQ View Post
    Long time lurker here, and I'm currently building up my first knolly.

    I picked up a used DHX5 coil, anyone know what spring rate I need for my Chilli? I'm 190 lbs. My Turner uses a different length spring, so I have to guess at what spring to buy.

    Thanks.
    I fluctuate between 182 - 190, and i use a 450 - seems to work really well.

  3. #3
    RideDirt
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    I'm on a van rc 200lbs and I have a 6oolb spring. How are you guys running such low spring rates?

  4. #4
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    At 190lbs, you are in between the 400lbs or 450lbs recommended spring rate. I'm usually around 195 and use a 450lbs spring when I have a coil on my podium or chilcotin.

    I think with this you should try to decide how you like your bike to ride and how you want it set up. If you have a preference then go that way but if you don't know, buy both and try them out to determine what you like the best. An extra $20 is worth it for the best set up.

  5. #5
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    I'm 215 ready to ride, and Craig at Avy told me to run a 500 when I got my shock back from him.
    If jackasses could fly this place would be an airport.

  6. #6
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    There was a great spring rate calculator posted here on MTBR a few years ago by FireDog46. It has kind of been lost and this is a good place to resurrect it.

    You can dowload the spring calculator from this link and run it into your favorite web browser (it works great in Firefox):

    X-Post: Mountain Bike Spring Rate Calculator V7.0

  7. #7
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    I am pasting it here for convenience as well (I had to remove a few sections of text to keep it within the 100KB limit of MTBR posts but the calculator is fully functional:

    Code:
    -->
    
    
    
    Mountain Bike Spring Rate Calculator V7.0
    
    
    
    
    
    
    
    
    
    
    Mountain Bike Spring Rate Calculator V7.0
    Total Riding Weight: (pounds) includes the rider and anything else added to the bike: lock, water bottles, etc.
    Rear Weight Bias: (percent) The standard formula is based on a 60:40, Rear to Front weight distribution. A more accurate way would be to use a bathroom scale under the rear wheel and a 2x4 under the front wheel to determine the true sprung weight at the rear wheel. Position your body according to your riding style. Enter this value for total weight and 100 for Rear Weight Bias. Alternatively use 55=XC, 65=FR, 70=DH, all others use the standard 60.
    Rear Wheel Travel & Shock Stroke: (inches or millimetres)
    Shock Sag: (percentage of shock stroke) The standard formula uses the Fox Shox recommended 25% of shock stroke. However, this tends to calculate too high a spring rate for the majority of riders. A more appropriate starting point would be 30% to 35%.
    Preload Adjuster: (number of turns) The standard formula ignores the effect of applying preload and tends to calculate too high a spring rate. Usually 1.0 is required to lock the spring to the shock body. Choose a preload value that will allow some plus or minus adjustment consistent with your required sag level and re-submit. A zero preload spring rate is found, then preload is applied to find an alternate spring rate taking into account the preload spring tension. Calculation is based on a linear progression.
    End-Coil Effect: (percent) Closed/Ground compression springs have a typically lower spring rate in their initial deflection range. The suggested value is a best guess of the effect ECE will have on preload adjustment. It is a percentage of the overall spring rate used in calculating the spring tension for the specified number of turns of the preload adjuster.
    Input Parameters: inches or millimetres
    Total Riding Weight: pounds
    Rear Weight Bias: percent
    Rear Wheel Travel: in or mm
    Shock Stroke: in or mm
    Shock Sag: percent
    Preload Adjuster: turns
    End-Coil Effect: percent
    Output Parameters: Travel Setting Three
    Leverage Ratio: travel divided by stroke
    Zero Preload Spring Rate: lbs per in
    Alternate Preload Spring Rate: lbs per in
    Suggested Spring Rate: lbs per in
    Suggested Spring Rate Preload Sag: percent

    Optional Spring Rates Constant Preload
    ( target preload as entered above )
    ( sag value is calculated from optional spring rate )
    ( never exceed spring preload limit - if unknown, never use more than 2.0 turns )
    ( more than 4.0 turns is not recommended )
    Preload Travel Setting One Travel Setting Two Travel Setting Three
    Travel:    Ratio:  Travel:    Ratio:  Travel:    Ratio: 
    Rate Sag Sag Rate Sag Sag Rate Sag Sag

    Optional Spring Rates Constant Sag
    ( target sag as entered above )
    ( optional spring rate is calculated from preload value )
    ( never exceed spring preload limit - if unknown, never use more than 2.0 turns )
    ( more than 4.0 turns is not recommended )
    Preload Travel Setting One Travel Setting Two Travel Setting Three
    Travel:    Ratio:  Travel:    Ratio:  Travel:    Ratio: 
    Rate Sag Sag Rate Sag Sag Rate Sag Sag

    Correction For Suspension Progression
    -----------------------------------
    The calculator assumes a linear suspension progression.
    For any deviation plus or minus <7% use the calculated spring rate.
    -----------------------------------
    Rising Rate ( 7% - 15% ) - Subtract 50 lbs.
    ( may require more preload )
    Extreme Rising Rate - rare ( 15% - 25% ) - Subtract 100 lbs.
    ( may require considerably more preload, possibly with a longer stroke spring )
    -----------------------------------
    Falling Rate ( 7% - 15% ) - Add 50 lbs.
    ( may require less preload )
    Extreme Falling Rate - common ( 15% - 25% ) - Add 100 lbs.
    ( may require as little preload as possible )
    ( extreme falling rate suspension bikes should be using an air shock )
    -----------------------------------
    ( or simply ride with the calculated spring rate and let personal preference decide )


    Mountain Bike Spring Rate Calculator V7.0
     
    Copyright (C) 2007 Michael R Young ( FireDog46 )
     
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.
     
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty
    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    See the GNU General Public License for more details.
     
    http://www.gnu.org/copyleft/gpl.html


    Anyone wishing to post this on their own web site is welcome to do so.
    Please leave everything intact, particularly the Copyright and Disclaimer.

    -->

  8. #8
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    Thanks for the replies and to NYbike for the awesome calculator. Very cool.

    So this leads me to a related question; what % sag do you guys run on the Chilcotin's in particular? Is there a general consensus on this or does knolly have a recommendation?
    Last edited by AndrewQ; 12-30-2012 at 06:18 PM. Reason: typo
    Taiwan could probably TIG weld a ham sandwich to a dictionary these days, but its been a while since they were doing brazing.

  9. #9
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    When I decided on which spring, I based my decision off the Knolly website (old version). The calculators i found online gave very different results compared to what knolly was recommending. At 185, I get a perfect 30pc sag using 450# spring.

  10. #10
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    Quote Originally Posted by AndrewQ View Post
    So this leads me to a related question; what % sag do you guys run on the Chilcotin's in particular? Is there a general consensus on this or does knolly have a recommendation?
    I believe Knolly recommends 30% as a starting point for sag. It is to some extent a function of rider preference, shock, and also terrain. I weigh 165lbs and am roughly 185lbs with a full camelback, riding clothes, and armor and usually run between 125psi and 130psi in a CCDB Air depending on how much I want the bike to sink into the travel. I have not used a coil shock on the Chilcotin but from experience with other frames I would guess that my spring rate would be 400-450lbs/in.

  11. #11
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    Quote Originally Posted by dulyebr View Post
    When I decided on which spring, I based my decision off the Knolly website (old version). The calculators i found online gave very different results compared to what knolly was recommending. At 185, I get a perfect 30pc sag using 450# spring.
    I'm right there with you. I'm 185 and running a 450# spring. Feels great.

  12. #12
    RideDirt
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    Wow , i should prob swap out my 600lb spring then for maybe 500? Cuz im like 200-210lbs geared up .

  13. #13
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    Quote Originally Posted by aedubber View Post
    Wow , i should prob swap out my 600lb spring then for maybe 500? Cuz im like 200-210lbs geared up .
    Yes probably. The calculator above states I need a 500 at 215, as does the online Fox calculator.

    600 is probably WAY oversprung for you.
    If jackasses could fly this place would be an airport.

  14. #14
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    Quote Originally Posted by nybike1971 View Post
    I believe Knolly recommends 30% as a starting point for sag. It is to some extent a function of rider preference, shock, and also terrain.
    So it sounds like the usual considerations for picking sag. Meaning there's nothing particular about the Chili's suspension that would change how much sag I should run?

    I guess that makes sense since it's not a vpp or dw link design.

    Thanks for the info, I'll order a few springs so I have a "tuning library" on hand to test. Still looking forward to my first ride.
    Taiwan could probably TIG weld a ham sandwich to a dictionary these days, but its been a while since they were doing brazing.

  15. #15
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    ~165 lbs + 10 for gear and running 350 lb. coil. Plush.

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