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Thread: stuttering caster wheel

  1. #1

    stuttering caster wheel

    When my chair picks up speed, like going down a ramp or something, one of my caster wheels starts making a stuttering sound. It jerks left and right really fast while the other caster rolls along normally. Does this mean that the bearings are bad and need to be replaced?

    If they do need to be replaced, how many bearings are there in each of caster and what size do I need? I have a Quickie TI and the diameter of the caster rim is 4 inches. The caster rim plus rubber tire has a 5 inch diameter.

    -Justin

  2. #2
    Hi Justin,

    Try giving the caster axle bolt/nut a tiny tightening. It may be just a little loose. When I adjust mine I tighten it up until it rolls kinda slow..... doesn't keep spinning for very long. Then I back the nut off just a little bit... just enough until it starts to spin very easily and freely. You could also remove the axle bolt and nut totally and give 'em a spray of WD-40 as a maintenance procedure.

    If that doesn't fix it then try doing the same thing with the fork stem. It could be a little loose too.

    I doubt the bearings are going bad... but ya never know. I just switched back to my old rims (24 inch rear wheels) because one bearing did go bad in my new rims. I kept spraying WD-40 on the axle to get rid of a squeak but that remedy only lasted a day or two before the annoying squeak came back. I looked at the bearing very closely and it had totally siezed-up... wasn't spinning at all. It was running on the axle and not the bearing.

    It was easier for me just to switch to my spare rims than to try and get that bearing out of the hub. I'll give it a try when I get around to it but they can be tough to remove. I'll probably take the pair of wheels to a bicycle shop.... after I order a new bearing and have the rims/spokes adjusted too. Maybe put some new tires and tubes on/in while they're in the shop. Keep the old ones as spares. It may be best to order the bearings by the pair... but they can be a little pricey. It depends on how "demanding" you are of performance.

    A bicycle shop will probably know how to "true up" a rim better than a wheelchair repair shop. They have more experience because they have those fussy bike riders (those people who wear those funny-lookin' helmets!) who they need to service and satisfy. Call them up first and see if they sell wheelchair tires or the type of tire that you like.
    "Be kind, for everyone you meet is fighting a great battle." - Philo of Alexandria

  3. #3
    Senior Member smokey's Avatar
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    I agree with Bob Clark....tighten the caster bolt a little. But also, check to see if your chair frame isn't bent with one caster wheel a fraction higher than the other...that would cause fluttering too.

  4. #4
    is it the caster or the fork that moves? If its the caster, I'm going with bad bearings.. might tighten just a smidge, or have bearings repacked.

    or .. is it the fork that holds it flipping? I tighten mine so they do not move on their own, but will with just slight resistance.

    the key though, is just tighten it up a smidge.
    Rick Brauer or just call me - Mr B

    http://www.riseadventures.org

  5. #5
    If it's the fork this will happen when one of your wheels is either higher or the fork is at a different angle to the other or if the castors as a pair are set up wrong. Many castors (all on adjustable chairs) should have an adjustment for angle and if yours are out (especially if it's just one of them) then that is most likely to be the cause.

    You need to loosen them off and realign them - there's usually a flat edge on the fork which needs to be at exactly 90 dgerees to the floor. On the Quickie Ti it's a PITA to do - you have to take the castor wheel off, then there is a torx screw in the fork leg that you can only see once the castor is off that has to be released - you then need to get the straight edge at the bottom of the fork where the castor axle goes in at 90 deg to the floor (use a set square or a book) and retighten. Then repeat on the other side. You have to do one side at a time. Hope that explains it. The procedure is set out in your owners manual which is available on the web if you've lost it.

    Unless you've really been mistreating your bearings it's highly unlikely that they'll be shot and even more unlikely that they''d cause the symptoms you describe if they were IMO. You can soon tell as the castors would feel loose on the axle - if they don't then I'm pretty sure they just need adjusting as described above

    Bob - dont know how your castor axles work but mine (on all 3 of my chairs don't work in the way you describe. The screws holding the axle in shouldn't clamp down on the bearings, the screws just clamp the axle into the forks and should be tight but if you take it apart the axle is bigger than the screw holes in the fork such that the fork can only ever be closed to the width of the castor axle. The castor wheels sit on the axle with a couple of spacers allowing the smallest amount of play. With modern sealed bearings this is how wheels work (and why you dont need to clamp in the rear wheels which work on a quick release axle pin. Older cup and cone bearings as used on some bikes (and possibly older / cheap wheelchair??) do however work by being clamped up. However Justins Quickie ti definately has the newer system that I describe.
    Russ - T2 complete

  6. #6
    Quote Originally Posted by russ1
    Bob - dont know how your castor axles work but mine (on all 3 of my chairs don't work in the way you describe. The screws holding the axle in shouldn't clamp down on the bearings, the screws just clamp the axle into the forks and should be tight but if you take it apart the axle is bigger than the screw holes in the fork such that the fork can only ever be closed to the width of the castor axle. The castor wheels sit on the axle with a couple of spacers allowing the smallest amount of play. With modern sealed bearings this is how wheels work (and why you dont need to clamp in the rear wheels which work on a quick release axle pin. Older cup and cone bearings as used on some bikes (and possibly older / cheap wheelchair??) do however work by being clamped up. However Justins Quickie ti definately has the newer system that I describe.
    Hi Russ,

    I thought my Quickie GPV was 7-9 years old but just found out it's only 5. So it isn't very old. But I don't believe the caster axles have changed since I bought my first Quickie Foldable 22? years ago.

    There are two sets of holes drilled in the fork. One set for 5 inch casters and the other for 8 inch casters.

    The bolt (which IS the axle) has one of those nuts on the end with plastic that acts as a locking or friction tightening feature. The bolt goes through the fork hole, then through a 3/8 inch spacer, then through the sealed bearing and hub and back out the other sealed bearing, through another 3/8 inch spacer and through the other fork hole. Simple as that. You then just screw on the nut (with the plastic locking or friction tightening feature) and tighten it up. If you tighten too much the wheel won't even spin. So you need to back off the nut until you get the caster to spin fast and free. If it's too tight the caster will be inhibited from spinning freely and if it's too loose it will wobble. You play with the tension until it spins freely but is still as tight as possible.

    Maybe they've changed in the past few years, I don't know. As soon as I get my new GPV (whenever that might be?) I'll check it out and see if Quickie has improved or changed the design. IMO, the design, as it is on my chair's forks, is somewhat "unsophisticated" but seems to work okay. I've never had an axle nut come loose.... the plastic on the nut appears to do it's job of keeping the nut from loosening or tighening on its own.

    Quote Originally Posted by Russ
    you then need to get the straight edge at the bottom of the fork where the castor axle goes in at 90 deg to the floor (use a set square or a book) and retighten.
    I use a plumb bob (monofilament and a weight... usually a nut) to get the fork bearing holder perpendicular to the floor. Since I just drilled an extra set of holes in my frame to increase the dump I had to re-adjust the front fork angle. It's strange how the fork angle is adjusted on my chair. There's a bolt with a head that's off-centered with a hole punched on the end of it to indicate what position it's in. It's a hexagonal bolt head so there's six positions to choose from. Actually there's twelve (??) since there are two of these bolts that "swivel" around a pin that goes through lower horizontal frame member. It's important to have the fork bearing-holder perpendicular to the floor or it makes turning the chair very awkward to do. It had me cursing a little more than usual until I adjusted it properly! What effect it has when going fast I can't say as I haven't test driven mine fast on a flat, smooth surface yet.

    The new GPVs look indentical to mine.. Except for the folding back... mine is completely rigid... the hinges on the backrest tend to break after awhile.... and they aren't covered under the lifetime warranty as part of the "frame" and are quite expensive to replace. You can see the two holes in the forks in this picture and the two fork angle off-centered adjustment bolts and frame-pin in this picture.

    I see they've designed the Quickie Ti's forks much differently than those on it's lowly cousin, the GPV. So you'll be "go to" guy for this model. But the casters definitely shouldn't wobble like on an old beat up shopping cart from the "Shop & Go"!
    "Be kind, for everyone you meet is fighting a great battle." - Philo of Alexandria

  7. #7
    The 'highspeed wobble'...anytime its happend to me its been the bearings.When you grab your fork does it wiggle? Is there any play in it? If there isnt then it maybe something else,this has always accompanied my wobble.

  8. #8
    Senior Member Spadfan's Avatar
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    Quote Originally Posted by Justin S
    When my chair picks up speed, like going down a ramp or something, one of my caster wheels starts making a stuttering sound. It jerks left and right really fast while the other caster rolls along normally. Does this mean that the bearings are bad and need to be replaced?

    If they do need to be replaced, how many bearings are there in each of caster and what size do I need? I have a Quickie TI and the diameter of the caster rim is 4 inches. The caster rim plus rubber tire has a 5 inch diameter.

    -Justin
    I believe from your description, the caster stem bearing pre-load is not adjusted correctly. The caster stem is the shaft the caster fork pivots on. There are usually two bearings carrying this stem with a nut on top and the fork on the bottom. The diagram is for a Quickie manual chair of some model, probably not your type. I just picked one that shows the parts. The items I have arrowed are adjustment nut (3) and the bearings (4). Unless this has been a problem for a long time the bearings are probably still OK and the nut just needs to be adjusted to pre-load the bearings.

    To do this take the dust cap off and have someone tighten the nut, while you are out of the chair. A deep well socket of the proper size and a ratchet handle works fine. Have them tighten it until the fork just starts to be hard to pivot, then back it off until the point is found where it spins freely again. That should do it. Leave the dust cap off and take it for a spin while your handy adjuster person is still around. That way he/she can make finer adjustments if necessary.

    I the worst spill I ever took was caused by a wobbling caster. One evening leaving work, I was going down a ramp and I just let’er roll. A caster started shimming and like a dumb ass I leaned over to see what was going on while I was still on this steep ramp. The chair tipped forward, the foot plates caught and I pitched out forward and landed at the bottom of the ramp. A little road rash was all that happened, fortunately.
    William M.
    T 6/7 Complete - 4/20/74

  9. #9
    Senior Member
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    FOR THE LOVE OF GOD......... DO NOT DO NOT DO NOT USE WD-40. It will ruin ur bearings as it will leave a sticky film, it gets sucked into the metal and destroy them. Use a light oil like 4 in 1 or sewing machine oil.

  10. #10
    Senior Member Spadfan's Avatar
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    After doing a little more looking at the Quickie parts manual seems my earlier post does not apply to the Quickie Ti chair at all. It does work for any chair that has caster stems of the type in my earlier post. The Ti chair is a completly different animal. I didn't do any searching for the maintenance manual and without it I personally don't have a clue as what the adjustment procedure would be. Ole Spad is stuck in the dark ages.
    William M.
    T 6/7 Complete - 4/20/74

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