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    Finding COG

    What do most quads run COG wise?

    #2
    I believe mine is 2.5". But I am not sure what being a quad has to do with determining COG.
    C5-6 Complete - 8/13/1982

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      #3
      What is COG?
      Tom

      "Blessed are the pessimists, for they hath made backups." Exasperated 20:12

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        #4
        I believe CoG is dependent on body shape, weight, and specific chair configuration.
        Chas
        TiLite TR3
        Dual-Axle TR3 with RioMobility DragonFly
        I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

        "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
        <
        UNKNOWN AUTHOR>

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          #5
          Originally posted by TomRL View Post
          What is COG?
          "Center of Gravity" on wheelchairs is actually the axle position, which changes how tippy your chair is. Cog is the horizontal distance from the front of the backrest canes to the centerline of the axle.

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          Chas
          TiLite TR3
          Dual-Axle TR3 with RioMobility DragonFly
          I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

          "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
          <
          UNKNOWN AUTHOR>

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            #6
            What chasmengr wrote is true. COG, center of gravity, derives from the wheelchair and wheelchair user interacting. It is usually changed by moving the rear wheels forward or backward on the wheelchair frame. It affects the amount of force that can be exerted without tipping over backward and how easy it is to pop up the front wheels to go over raised thresholds, etc. The seatback angle and dump can also affect the COG. Those are the basics.
            You will find a guide to preserving shoulder function @
            http://www.rstce.pitt.edu/RSTCE_Reso...imb_Injury.pdf

            See my personal webpage @
            http://cccforum55.freehostia.com/

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              #7
              Just wondering what others liked. Mine is at 2" and I run about a 4 inch dump. Carrying over my current configuration to a non adjustable chair is a little nerve racking as it probably will not be the same.

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                #8
                What chair are you considering? Some nonadjustable chairs still have an adjustable CoG (e.g., TiLite TR). Others do not.
                Chas
                TiLite TR3
                Dual-Axle TR3 with RioMobility DragonFly
                I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

                "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
                <
                UNKNOWN AUTHOR>

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                  #9
                  Originally posted by Brianm View Post
                  But I am not sure what being a quad has to do with determining COG.
                  Southpaw does have a point. Most quads have a much lower upper body mass than most paras. That can certainly affect how tippy a chair is.

                  OP--The Center Of Gravity on any wheelchair is highly subjective to its configuration and the user. That's why almost every chair manufactured is designed to have at least some range of COG adjustment. Even TiLite's minimally adjustable ZR has a small amount of adjustment between the camber clamp and CG bracket, even if it is just a few holes. A person's needs may change over time depending on changes in posture, weight, or even very heavy clothing, like a bulky leather jacket. That's why I would never purchase a chair with the COG welded in place (not that you would).

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                    #10
                    Originally posted by ala View Post
                    The Center Of Gravity on any wheelchair is highly subjective to its configuration and the user.
                    Agreed.

                    That said, I'd guess most quads have COG set somewhere between 1.0-3.5"

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                      #11
                      I don't know about SCI and CoG but I am running 2.25". The thing is as Chad and SCI said, setting it, depends on a lot of things. If you change you back angle even slightly, that can affect your balance. Small changes can have large affects. I hope your chair is adjustable if you are still deciding on your CoG. I suggest making small changes. By the way, a lighter front end (tippier chair) will making pushing easier but you give up stability. I want to be one of the cool kids and go with 3.5 or more but I hate falling backwards and have done it a few times. I go for stability.

                      Choosing CoG is a complicated thing because it also affects your pushing and comfort. Get lots of info and try different settings. I've had friends with settings that seemed crazy but, it worked for them. One friend had a front end so heavy, while in it I couldn't pop enough wheelie to move the castors off the ground at all. It was like he had a sack of cement up front but, he'd lived that way for years, traveling all over the country and the world. He knew what he was doing. Another friend had a super light front that came up whenever he pushed. Settings are personal, find what works for you.

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                        #12
                        Originally posted by Southpaw View Post
                        Just wondering what others liked. Mine is at 2" and I run about a 4 inch dump. Carrying over my current configuration to a non adjustable chair is a little nerve racking as it probably will not be the same.
                        Changing chairs will throw the COG way off. Heck, when I went from a ZR to a ZR2, even with exact same specs, the ZR2 felt like a tank in the front.

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                          #13
                          Thanks for all the advice guys.

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