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    new chair, cant get up some ramps.

    I got this new chair because my ass is actually getting larger and had to switch from my wonderful Kuschall chrome tank to what I thought would be a lighter and more maneuverable chair.

    I got a TiLite Aero Z and I love it on flat ground. But for some reason, I cannot seem to get up the short ramps that are like curb cuts and such in parking lots, you know the kind that are less than three feet long and cut up to the sidewalk level from say a parking lot or just a lump of cement they put in as an afterthought. I feel like I am going to tip over backwards and I just can't push up the damn things.

    I have no trouble getting up a longer ramp, but have had to ask strangers to push me up these hellish little faker ramps that seem to be everywhere I need to go.

    My new chair has a shorter wheelbase from the casters to the rear wheels and is a 90 degree angle like my old Kushall. Could this be the problem?

    Help!
    Anything worth doing, is worth doing to excess

    #2
    Originally posted by skippy13 View Post
    I got this new chair because my ass is actually getting larger and had to switch from my wonderful Kuschall chrome tank to what I thought would be a lighter and more maneuverable chair.

    I got a TiLite Aero Z and I love it on flat ground. But for some reason, I cannot seem to get up the short ramps that are like curb cuts and such in parking lots, you know the kind that are less than three feet long and cut up to the sidewalk level from say a parking lot or just a lump of cement they put in as an afterthought. I feel like I am going to tip over backwards and I just can't push up the damn things.

    I have no trouble getting up a longer ramp, but have had to ask strangers to push me up these hellish little faker ramps that seem to be everywhere I need to go.

    My new chair has a shorter wheelbase from the casters to the rear wheels and is a 90 degree angle like my old Kushall. Could this be the problem?

    Help!
    Might it be that the center of gravity is set too far forward? Just a thought.
    E
    There is no such thing as a stupid question but there sure are a lot of inquisitive idiots. -modified from despair.com

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      #3
      Sounds like gravity. Are you able to lean your upper body forward and still operate the wheels to go up? That would help COG without any mechanical change to the chair.

      Comment


        #4
        Originally posted by rlmtrhmiles View Post
        Sounds like gravity. Are you able to lean your upper body forward and still operate the wheels to go up? That would help COG without any mechanical change to the chair.
        No amount of leaning makes me feel safe. I just sort of dead stop on the ramps and cannot get to the top.

        You might be right about the COG. I had it set for all the weight to be on the front of my old Kuschall. I just felt better about it. The trouble with my new chair is that there is less 'front' on this chair. The tubing on the Kuschsall extended about an inch or so farther than my seat pan because I needed the extra protection for my legs. My old chair was a good battering ram for doors.
        Anything worth doing, is worth doing to excess

        Comment


          #5
          I agree (fwiw); sounds like a CoG issue to me.

          I can propel my AeroZ1 up ADA ramps just fine and up curb cuts with some effort, but have just ordered a set of MagicWheels to help me navigate the long, steep hills in my neighborhood. If adjusting the CoG doesn't help you, consider MWs. They let me try a set free for two weeks to see if I liked them.

          When I installed the trial MWs, I had to move my axle back, or I'd go over backwards on the hills I was climbing.
          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>

          Comment


            #6
            COG. I almost never biffed backwards in my kuschall. Seems I'm always bashing my cranium since its premature death. It sucks tho, moving it back will make it harder to push.
            Blog:
            Does This Wheelchair Make My Ass Look Fat?

            Comment


              #7
              Thanks everyone. I thought it might be something simple and I I'll try to adjust tomorrow. I really don't like my new chair very much but I just feel so ungrateful. I know there are others who would kill to have a nice chair like this.
              Anything worth doing, is worth doing to excess

              Comment


                #8
                I agree, it sounds like a center of gravity issue and I doubt you'll be able to adjust it enough due to the design of the chair. You can add anti-tippers though. I just go up backwards when it gets tough or too tippy.
                I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

                Comment


                  #9
                  Your placement of hands on the wheel to propel will also change COG and other things. Do you wear a seat belt?

                  Comment


                    #10
                    Another thing that could help without any mechanical adjustment is "playing/adjusting" your overall lenght of 1 single stroke of your arms on the wheels to something shorter. The shorter distance should provide more stability bur will require more strokes to go the same distance.

                    Comment


                      #11
                      Are your arms reaching down onto the pushrim the same distance as previous chair. For example, sitting straight up where do your fingertips reach on the middle of the wheel.....the same in both chairs?

                      Do you have any dump in chair? Could make a difference.

                      Comment


                        #12
                        Originally posted by skippy13 View Post
                        My new chair has a shorter wheelbase from the casters to the rear wheels and is a 90 degree angle like my old Kushall. Could this be the problem?
                        Absolutely. The shorter wheelbase on the Aero Z is almost certainly the primary underlying cause of the problems you are encountering getting up shorter ramps with your new chair. A shorter wheelbase can have an adverse effect on a number of factors that can adversely affect your ability to negotiate ramps, thresholds, and curbs.

                        I discuss each factor separately in subsequent posts. While you are having a problem using what most would consider to be a relatively state-of-the art custom ultralight rigid frame, the concepts I'll discuss go back to "classic" studies on wheelchair stability and efficiency that were published during the 80's and 90's. Names associated with these studies include Brubaker, Tomlinson, Kirby, and Cooper. At the time, rigid frames were the exception rather than the rule, the lightest models on the market would be considered heavy by today's standards, 6-8" casters were the norm, and front frame/hanger angles > 70 degrees were rare.

                        Due to advances in wheelchair technology and design, understanding/applying the concepts examined in many of these studies is more important now than than it was "back in the day".

                        I'll cover many of these in separate posts throughout the weekend.

                        Comment


                          #13
                          Effect of Wheelbase on Chair Orientation In a Wheelie

                          The first effect of having a shorter wheelbase/frame length relates to the orientation of the chair when the casters are not on the same level as the rear wheels. The two chairs shown in the illustrations below are identical in every respect except for a 2.5" shorter frame/wheelbase on the red chair.

                          85 Degree Short Frame with a 15" wheelbase....



                          85 Degree 2.5" longer frame with a 17.5" wheelbase...



                          Although the casters on both chairs are at same height, the red chair would have a harder time ascending the curb because it must approach at a slightly steeper angle. One might argue that in order to maintain stability, the user of either chair needs to lean forward as much as possible. If that is the case, would a 2 degree difference in the orientation of the chair matter?

                          Before answering that question, try balancing in a wheelie and see how many degrees you can go away from the balance point before having to reestablish equilibrium. As for myself, I have about 10 degrees either way in my 85 degree short cantilevered frame. A difference of +/-2 degrees could be significant.

                          Comment


                            #14
                            It can take a lot of time and adjustment when you get a new chair, for that reason I never look forward to switching chairs because I always know it's going to be a lot of work. Maybe you could go to a local SCI rehab place and see if they can help you out to get things right? Or even a local DME place as long as they can bill your insurance because if you had to pay cash they'd probably charge a few hundred bucks for an hour of time.
                            "Life is about how you
                            respond to not only the
                            challenges you're dealt but
                            the challenges you seek...If
                            you have no goals, no
                            mountains to climb, your
                            soul dies".~Liz Fordred

                            Comment


                              #15
                              @SCI_OTR You rock! Thank you for the illustration.... very helpful!
                              There is no such thing as a stupid question but there sure are a lot of inquisitive idiots. -modified from despair.com

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