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ISIS bearing source 42x22x12, besides Unicycle.com?

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  • LargeEddie
    replied
    Originally posted by finnspin View Post
    Take a 6004 bearing. Find a friend with a lathe, and have them turn of 2mm of the inside diameter.
    I have a lathe. You can think of me as a friend if you'd like. But that bearing race is hardened and it would have to be ground.

    Keep this in mind: The inside dimension of the bearing was made bigger to give more strength to the axle that passes through it. The bearings are rated for loads many times higher than we put on them and usually fail because of rust, grit, or salt getting in, not from load.

    Before ISIS, aggressive unicyclists used to break axles all the time. See the George Peck video where he puts "just a few of" the broken hubs he'd collected on the table. IIRC (been a while) stress at the outside and most heavily loaded part of a beam-loaded circular shaft varies with the 4th power of the diameter, so every mm counts.

    But I don't see a problem getting "6004/22" bearings at present. I have an eBay "Schwinn style" square-taper hub that takes 6203-2RS-5/8 bearings because the bearing surface on the axle is 5/8" instead of the usual 16 mm. It turned out that they're cheaper and more plentiful than the "standard" size because they're used on a popular piece of farm equipment or something. It's all down to how many distributors want to place orders for that size. Bearing manufacturers don't forget how to make them!

    Call it standard, non-standard, or a non-standard standard but one search for "6004/22" returned dozens of sources for me. Stock up now if you're worried about it I guess.

    Buy whatever hub is the new standard in that very distant future.
    For sure! You'd have to unlace the wheel to do any hub machining to make another bearing fit anyway. You'd do better to lace in a new hub that came with the new standard bearings already installed if it came to that.
    Last edited by LargeEddie; 2019-03-25, 01:18 AM.

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  • mrfixit
    replied
    Iíve wore out one set in a 1 1/2 year, the noise is driving me nuts. I donít think weíll have a problem getting bearings. We have unicycle. Com. They can always get a source to make more.

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  • finnspin
    replied
    Originally posted by Go Uni View Post
    You assume such a bearing could be available if needed but non-standard bearings are not guaranteed to be available. Then what to do?
    Take a 6004 bearing. Find a friend with a lathe, and have them turn of 2mm of the inside diameter.

    Buy whatever hub is the new standard in that very distant future.

    Assuming it's probably the outer ring that gave away (as it's usually the case) take bearing apart, and rebuild it with parts of a 6004 series bearing.

    Take a 61905 bearing, and machine two spacers (one for the inside ring, one on the outside so it doesn't move side to side in the frame)

    Buy 3 sets of bearings when I notice ISIS hubs on unicycles are dissappearing, and have enough of them for the rest of my unicycle career.

    I've never experienced a bearing failure that was so fatal that it kept me from being able to ride, it's only the noise that gets annoying usually. (It has apparently happened to others, but i'm pretty sure they overtightened the bearing caps at some point.) I've ridden with my tire taped to the rim, since the bead broke, and a JB welded seatpost for a short time, since I was travelling and couldn't order parts, I think I'll find a solution if I need to.

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  • JimT
    replied
    Originally posted by Go Uni View Post
    Well, apparently the ISIS standard for bicycles does not include standard bearings. Or if they are available as standard bearings for bicycles then why do they not fit unicycles?
    ISIS hub bearings on bikes is very different then unicycles. Unicycles have to have a separate bearing on the end of each fork leg where a bike has bearings in a single tube in the bike frame. Some do use sealed bearings but the size/configuration is much different then required on a uni.

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  • Go Uni
    replied
    Actually, until this bearing topic thread got posted here last week I was aware there are larger and smaller unicycle bearings and I never gave bearings any more thought than that.

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  • Go Uni
    replied
    Originally posted by mowcius View Post
    I suspect that we'll all die due to climate change before ISIS spindle bearings become completely unavailable.

    I think I've replaced two sets of bearings on all of my unicycles in around 9 years, so with the number I've got spare, I'm probably set for life!
    Hehehe! You likely are quite right! And yes, most bearings can take a lot of use and moderate abuse before they bugger out.

    My background is mechanical engineering and I am trained to consider extreme possibilities and situations. That is what I professionally do.

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  • Go Uni
    replied
    Originally posted by MrImpossible View Post
    I think you all are getting a little carried away with your talk about machining spindles down...
    Are you rationing thought and ideas around here? It took me all of a few seconds to have a thought, then not many seconds to put it here and then I have not lost a single second of sleep about the matter.

    Originally posted by MrImpossible View Post
    Alibaba showed several Chinese manufacturers selling them cheap...
    And that was followed by discussion about the quality of those same bearings. The idea here is to be progressive thinkers, right?

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  • Go Uni
    replied
    Originally posted by OneTrackMind View Post
    Nothing compared to why anyone would be concerned about whether a bearing that doesn't often need to be replaced costs $10 or $20 on a $500+ machine.
    You assume such a bearing could be available if needed but non-standard bearings are not guaranteed to be available. Then what to do? All I did was to ask myself that same question and then spend a few moments here on my keyboard. You are suggesting such a question could be unfit to discuss?

    Originally posted by OneTrackMind View Post
    Also remember that the ISIS standard was developed for bicycles. The engineers who put it into unicycles didn't have carte blank as the starting point.
    Well, apparently the ISIS standard for bicycles does not include standard bearings. Or if they are available as standard bearings for bicycles then why do they not fit unicycles?

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  • mowcius
    replied
    I suspect that we'll all die due to climate change before ISIS spindle bearings become completely unavailable.

    I think I've replaced two sets of bearings on all of my unicycles in around 9 years, so with the number I've got spare, I'm probably set for life!

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  • MrImpossible
    replied
    I think you all are getting a little carried away with your talk about machining spindles down because UDC bearings might disappear. I see them on the QU-AX web site, and probably any manufacturer of ISIS hubs sells them as replacement parts.

    And they might be "non-standard" but that doesn't mean you would have to find somebody to custom make one for you. Alibaba showed several Chinese manufacturers selling them cheap. No idea what the shipping would be but you could probably get a lifetime supply for all your unis for the price of having an axle machined. For example here and here.

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  • OneTrackMind
    replied
    Originally posted by Go Uni View Post
    What I find curious is why the need for an expensive to develop non-standard bearing.
    Nothing compared to why anyone would be concerned about whether a bearing that doesn't often need to be replaced costs $10 or $20 on a $500+ machine.

    Also remember that the ISIS standard was developed for bicycles. The engineers who put it into unicycles didn't have carte blank as the starting point.

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  • finnspin
    replied
    Originally posted by Go Uni View Post
    What I find curious is why the need for an expensive to develop non-standard bearing. A designer could know what size of bearing they need but then as is commonly done search for a standard bearing of the same or slightly larger size and then make adjustments to their design if need be. Sure, there are situations where nothing but an exact design match will do, but for a unicycle? ISIS is a great system but consumers now have only one source for bearings. Oh well, Schwinn used to routinely do that sort of thing with its bicycle tires.
    Probably because it's the cheapest method overall as a OEM. It's just having the bearing supplier turn 1mm more of the radius of a 6004 series bearing. If you go with a 6005, your outside diameter changes 5mm, so you might not be able to use the same machined bearing cap parts as with square taper bearings, the use of shims to convert between the two is made impossible too. I'd guess that previous onza and other outdated splines used 42 mm outside diameter, and 12 mm wide bearings too, so you would want to keep that compatability.

    If you go large on the inner diameter, you are throwing compatibility to the previous frames away. You also have to get larger round stock, and machine more of it to get your Isis spline, and to keep similar weight. Machine time is very expensive, for the bearing manufacturer turning 2mm more of the inner diameter is a lot less machine time that for the hub manufacturer to turn the 30mm stock you need to get a 6005 bearing on there down to 21.2 mm for the Isis spline.

    Most unicycles never get a bearing replaced, so the aftermarket supply being limited is pretty irrelevant.

    That's my analysis at least.

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  • Go Uni
    replied
    Ah, time out for coffee.

    What I find curious is why the need for an expensive to develop non-standard bearing. A designer could know what size of bearing they need but then as is commonly done search for a standard bearing of the same or slightly larger size and then make adjustments to their design if need be. Sure, there are situations where nothing but an exact design match will do, but for a unicycle? ISIS is a great system but consumers now have only one source for bearings. Oh well, Schwinn used to routinely do that sort of thing with its bicycle tires.

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  • Go Uni
    replied
    Originally posted by OneTrackMind View Post
    That last 2 mm has a radius where it comes off the spline. Without it there would be a sharp corner which would focus the stress. The result would be dramatically weaker.
    I can see that and for the same reason as you mentioned I would not change it but it just looked like there was more diameter metal available. Apparently pictures have limits for me.

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  • Go Uni
    replied
    Originally posted by JimT View Post
    The out side diameter of the spline is 21.2mm, so turning the spline and shaft down to 20mm would sacrifice some strength in the spline as well as the shaft.
    OK, I was interested in that but relative to the inside diameter of the bearing the spline outside diameter just looked smaller than it actually is.

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