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    One dopey question, maybe two.

    Are all caster diameters measured at the caster rim or the outer 'tyre' dimension? All this time I have been assuming that the size is derived from the rim diameter.

    Next. I was told today that back canes on ZRA folding back chairs cannot be supplied in titanium, only in aluminium.
    I have opted for fold down push handles. - Thinking on, fold down handles on a 14"(max) back are too low for most adult people pushing; the reason I find them convenient is for handling when removing the rear wheels.

    #2
    its the outside diameter of the tire.

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      #3
      Thanks BFD ‚Äč

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        #4
        Yeah measurement is from outside diameter of the tire.

        I have 14 backrest too with fold down handles. I like them a lot for the same reason you do. Titanium back canes aren't used because titanium has a tendency to snap off when breaking while Aluminum will bend a bit before breaking. They aren't that much lighter than Al. considering they are just two tubes of metal.

        I use a 4x1 1/2" caster also make sure you get the 4" deep rigidizer bar on the back. It gives the extra room needed is you ever decide on a solid back,

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          #5
          Originally posted by Patrick Madsen View Post
          Yeah measurement is from outside diameter of the tire.

          I have 14 backrest too with fold down handles. I like them a lot for the same reason you do. Titanium back canes aren't used because titanium has a tendency to snap off when breaking while Aluminum will bend a bit before breaking. They aren't that much lighter than Al. considering they are just two tubes of metal.

          I use a 4x1 1/2" caster also make sure you get the 4" deep rigidizer bar on the back. It gives the extra room needed is you ever decide on a solid back,
          I wouldn't be surprised if the Al back rest is lighter than the Ti one. On pieces they don't thin out the wall thickness a lot on, like the axle tube (one I know for sure), their Al parts are actually lighter.

          Oddly, titanium folding backrest IS an option on the Aero Z, I have it, double checked my quote, so I am thoroughly confused!

          (I also see it as a $195 option on the "international" ZR order form too. Slow_runner might not have been given good info.)
          "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

          "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

          Comment


            #6
            Originally posted by Oddity View Post
            I wouldn't be surprised if the Al back rest is lighter than the Ti one. On pieces they don't thin out the wall thickness a lot on, like the axle tube (one I know for sure), their Al parts are actually lighter. Oddly, titanium folding backrest IS an option on the Aero Z, I have it, double checked my quote, so I am thoroughly confused! (I also see it as a $195 option on the "international" ZR order form too. Slow_runner might not have been given good info.)
            Hi Pat and Odd. The 5" casters are scripted set at the mid hole which will give me the option of using 4" without affecting the chair configuration - assuming that it doesn't need further tweeking.
            I believe that the reason the Titanium backrest option was not offered/available is because at the scripting meet I chose the fold down handle option on a fold down back. Could that be correct?

            Apart from being handy (for me) when maneuvering the chair from my bed and when dismantling for transfer, the handles provide support on occasion when reaching round and back.
            I have a ZRA loan chair from a good friend for my wife to use with the bastard cancer that does its best to debilitate her. I had some spare clamp on canes in my bits box that I fitted for her to enable to be more comfortably pushed by her fiends and family members. They are useful and practical but an ugly option; the fold downs are a cleaner look.

            Comment


              #7
              There are 3 order forms for the ZR. US, Canadian, and International. Assuming you're using the International...

              (they can all be found here)

              ...there is an exclusion listed for the titanium folding back rest (ZSB2) with Bolt-On Push Handles (ZSB8 and ZSB9), but NOT with the folding push handles (ZSB6 or ZSB7).

              Might be worth a little push back about, if you really wanted it. The round bar looks neat, which is why I opt'd for it.



              Originally posted by slow_runner View Post

              Hi Pat and Odd. The 5" casters are scripted set at the mid hole which will give me the option of using 4" without affecting the chair configuration - assuming that it doesn't need further tweeking.
              I believe that the reason the Titanium backrest option was not offered/available is because at the scripting meet I chose the fold down handle option on a fold down back. Could that be correct?

              Apart from being handy (for me) when maneuvering the chair from my bed and when dismantling for transfer, the handles provide support on occasion when reaching round and back.
              I have a ZRA loan chair from a good friend for my wife to use with the bastard cancer that does its best to debilitate her. I had some spare clamp on canes in my bits box that I fitted for her to enable to be more comfortably pushed by her fiends and family members. They are useful and practical but an ugly option; the fold downs are a cleaner look.
              "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

              "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

              Comment


                #8
                I do have the US, Canadian and International in PDF now. It's just coming up to 2.30am, I will look at that again later today.
                I have more thought to apply to my chair prescription decisions before it is final. Thank you for the direction Odd.

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                  #9
                  On my itemised script I have reduced the seat length and requested a 18"wide x 17" seat frame with +2" . The trial chair is 18 x 18 and another inch would be helpful with transfers .I am also considering requesting 80 degrees to give another 1.5" at the footplate.

                  My question is this - If the frame length is increased, do the caster arms remain the same length or are they stretched back closer to the COG position to maintain a shorter squarer wheelbase?
                  If that is the case, I may need to request a change via Designs Unlimited DU100062 ?
                  Last edited by slow_runner; 5 Jun 2021, 9:39 AM.

                  Comment


                    #10
                    AFAIK they only stretch the frame and leave the relationship of everything in the from the same.
                    When I ordered my aluminum chair, trying to keep it as close tony original Ti Lite? sport?, they insisted I needed an extra inch.
                    It counts! This chair has much more trouble maneuvering.
                    69yo male T12 complete since 1995
                    NW NJ

                    Comment


                      #11
                      [QUOTE=pfcs49;n2910014]AFAIK they only stretch the frame and leave the relationship of everything in the from the same.
                      When I ordered my aluminum chair, trying to keep it as close tony original Ti Lite? sport?, they insisted I needed an extra inch.
                      It counts! This chair has much more trouble maneuvering. [ /QUOTE]

                      Is that the chair in your 'Transforming a scooter' thread pfcs49? What is the seat/frame configuration of that chair and could you measure that relationship between the caster and axle centre for me? I want to see how it relates to this trial example. I have the shipping specs to calculate/compare with its current setting.
                      I will measure and compare with the 2GX also - that is a long chair that I find works OK for me, yet I haven't measured that caster to axle relationship.

                      Click image for larger version  Name:	image_62701 -.jpg Views:	0 Size:	307.8 KB ID:	2910016

                      Comment


                        #12
                        Originally posted by slow_runner View Post
                        On my itemised script I have reduced the seat length and requested a 18"wide x 17" seat frame with +2" . The trial chair is 18 x 18 and another inch would be helpful with transfers .I am also considering requesting 80 degrees to give another 1.5" at the footplate.

                        My question is this - If the frame length is increased, do the caster arms remain the same length or are they stretched back closer to the COG position to maintain a shorter squarer wheelbase?
                        If that is the case, I may need to request a change via Designs Unlimited DU100062 ?
                        The caster assembly and footrest move forward by the same amount. If they didn't, the chair would become less stable. The reason for the extra room is transfer stability (and foot placement for some) so leaving the casters in the shorter position would work against that, so Im 99% sure they move too. They did in my TiLite with +1", but I dunno if that is always the case. I suspect it is though.
                        "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

                        "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

                        Comment


                          #13
                          Originally posted by Oddity View Post

                          The caster assembly and footrest move forward by the same amount. If they didn't, the chair would become less stable. ............................. They did in my TiLite with +1", but I dunno if that is always the case. I suspect it is though.
                          If that is the case Odd, I will look at bringing the caster position back closer to it original.
                          It would be better if clients had access to working desktop models to 'see' how various configerations might function. Still working in conjunction with the experience of the OT and the script writer from Permobil.
                          AND the advice from members here based on their experiences.

                          Comment


                            #14
                            Be aware they do have 'stability tolerances' that they won't readily compromise on. A member of the Sunwheeler's basketball team I knew years ago went around and around with them over forward stability, in particular. (He wanted a 18" tall 90deg frame with no dump AND Froglegs. LOL.) So, if the casters are back far enough to cause the chair to easily tip over with weight on the footrest, you might run in to problem with approvals on the design. Particularly if the caster placement you want puts them behind (toward the rear) of the vertical line of force, from where your hand is on the frame, to the floor, during a transfer. You could end up with a geometry that causes the chair to endo during a transfer with casters too far back from the front of the chair!
                            "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

                            "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

                            Comment


                              #15
                              Update: I just compared my +1" 85deg Aero Z frame with the CAD drawing I got for it before adding the +1" spec. The CAD drawing shows a wheelbase of 13.35. The real frame (after +1" was added) has a measured of wheelbase of 14.00. They moved forward but not the entire amount.
                              "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

                              "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

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