Announcement

Collapse
No announcement yet.

"Crunching" in front end of my ZRA?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    "Crunching" in front end of my ZRA?

    I wrote some time ago about this, and Tilite said to replace the caster bearings and you all were a BIG help with that. Well, I finally got the bearings replaced and the "crunch" is still there, seemingly on the right. Any ideas? This is getting annoying!
    Thanks!

    #2
    pics?
    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


      #3
      Did you also change the fork bearings? If so and you still hae a crunch, you may have a slightly bent axel.

      Comment


        #4
        I had this noise on my ZRA too… Lots of rust in fork bearings on one side (after taking 2 or 3 showers with it I'm afraid)
        I had to change them, and it was a hassle… but all is OK now.
        Try to move slowly the fork, check if it's smooth without any hard spot.
        C6-7 since mid 2002, no hand control nor triceps.
        my website & my job (in France): Accessibility advisor www.acceslibre.eu
        Also working on a French research about Peer counseling and Empowerment.

        Comment


          #5
          The ZRA is the most difficult and frustrating chair I've ever had to work on in my forty years of wheelin'

          Comment


            #6
            Oh rats!!! Now I KNOW I'm in way over my head. FORK bearings?!!!! So, do I use the same size I replaced in the casters? I have extras. I used Bones Super Reds. There's no binding, or whatever, when I turn the fork, robotnik. Thanks all.

            Comment


              #7
              Yes, Lynne, unfortunately… there's also bearings in the forks !
              And, of course, they are NOT the same as your caster ones…

              BUT hopefully (?) if you can't find any hard spot when turning it, nor noise or gap inside, SO surely the problem isn't there…

              Where ? why ? no ideas, at this moment… sorry.
              C6-7 since mid 2002, no hand control nor triceps.
              my website & my job (in France): Accessibility advisor www.acceslibre.eu
              Also working on a French research about Peer counseling and Empowerment.

              Comment


                #8
                Originally posted by robotnik View Post
                Yes, Lynne, unfortunately… there's also bearings in the forks !
                And, of course, they are NOT the same as your caster ones…

                BUT hopefully (?) if you can't find any hard spot when turning it, nor noise or gap inside, SO surely the problem isn't there…

                Where ? why ? no ideas, at this moment… sorry.
                But I thought the fork bearings are press-fit. How could anyone replace those? I've been told the chair needs to go back to the factory to replace them.

                Comment


                  #9
                  robotnik, I had to smile at your response. The icons represent my feelings to a "T". Thanks for the humor today. I needed it. Guess I need to call TiLite again, although I'm not sure what good that'd do.
                  grommet, how does one KNOW fork bearings is the problem? Wish I didn't live in such a rural area. Nobody can take a look.
                  Last edited by Lynne; 19 Jun 2013, 4:37 PM. Reason: additional info

                  Comment


                    #10
                    Originally posted by grommet View Post
                    But I thought the fork bearings are press-fit. How could anyone replace those?
                    You're right. The lower one comes easily when removing the all fork. But the upper bearing is strongly tighened on the axle. We (I say "we", but as I'm a quad without finger function, my father does the mechanics for me. I can only use my brain… and not too much !) had to :
                    - break in two parts the outside ring of the bearing, using a big hand-vice,
                    - separate all the balls and cut their support,
                    - cut in two parts the inner ring with a small grindstone on a Dremel.
                    Not easy… but doable.

                    Lynne, any good mechanic will be able to check your fork and their bearings, without removing them. That's a small part of their job.
                    C6-7 since mid 2002, no hand control nor triceps.
                    my website & my job (in France): Accessibility advisor www.acceslibre.eu
                    Also working on a French research about Peer counseling and Empowerment.

                    Comment


                      #11
                      Originally posted by robotnik View Post
                      You're right. The lower one comes easily when removing the all fork. But the upper bearing is strongly tighened on the axle. We (I say "we", but as I'm a quad without finger function, my father does the mechanics for me. I can only use my brain… and not too much !) had to :
                      - break in two parts the outside ring of the bearing, using a big hand-vice,
                      - separate all the balls and cut their support,
                      - cut in two parts the inner ring with a small grindstone on a Dremel.
                      Not easy… but doable.

                      Lynne, any good mechanic will be able to check your fork and their bearings, without removing them. That's a small part of their job.
                      Thanks for explaining but yeah, that's what I thought. I've done stuff like that and it is exhausting. Days of work. When there hasn't been a choice I've done that kind of work but getting older and things being harder I no longer want to be the hands-on hero I was in my youth. I keep trying to think of what about disability doesn't suck and I keep coming back to shoes. Gotta admit, my shoe budget ain't much. ;-)

                      Comment


                        #12
                        Sure, I understand and agree with you !
                        After having made all the mechanics on my motorbike and my MTB (I'm an "ex" Enduro rider, on a 360 KTM and all terrain enthusiast on a bike) I HATE having things done by anyone else.Difficult to find a "good" mechanic you can rely on…

                        But if we can come back to this post, I think Lynne has still this issue !! Am I right ?
                        Lynne, try to describe this "crunching" as best as you can…
                        C6-7 since mid 2002, no hand control nor triceps.
                        my website & my job (in France): Accessibility advisor www.acceslibre.eu
                        Also working on a French research about Peer counseling and Empowerment.

                        Comment


                          #13
                          Originally posted by robotnik View Post
                          But if we can come back to this post, I think Lynne has still this issue !! Am I right ?
                          Lynne, try to describe this "crunching" as best as you can…
                          Well............let's see. I'm saying crunching because it's a dull, short snap when it occurs. Like only one sound of it each time. It happens when the front end is loaded (feet hanging down), usually when I'm transitioning from tile to carpet, or the reverse, or changing direction sharply. Sounds to be coming from the right side. I'm not aware of it when I'm freely wheeling around with some speed. It's when I'm moving very little, changing surfaces, dressing, forward, back, etc. Does this help? AND it doesn't always DO it!

                          Comment


                            #14
                            Lynne,

                            Here's something easy to try. If your caster wheels use small spacers between the caster wheel bearing and the caster fork, clean the ends of these spacers (where they contact the bearing and the fork) and apply a very small amount of grease to these surfaces before reassembling the wheel into the fork.

                            Many chairs use a 5/16" bolt for the caster wheel axle but the bearing is actually 8mm ID. There's only a few thousandths of an inch difference, but it can be enough to cause a condition called stick-slip. When the caster bearing shifts position against the spacer, it can make a snapping sound like you describe.

                            Lubricating that area will not resolve the problem permanently, but the real solution isn't nearly as easy.

                            Be sure not to over tighten the axle bolt/ nut. In fact, leaving it just shy of snug will reduce the tendency for the the wheel to snap back and forth against the spacers.

                            Comment


                              #15
                              Hey Black Alloy, that sounds like a real possibility! I actually have THREE spacers between my bearings and fork on EACH side! So any ONE of those areas could be the culprit. I've thought of getting the one wider spacer for each side but never did. Can't wait to try your suggestion! Thanks!

                              Comment

                              Working...
                              X