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  1. B

    Q128C sources?

    Can't help with your parts search; but if you are in UK/Europe and want to get shot of your broken Q128H, I will buy it, if the price (and shipping) are reasonable. (And then I noticed "North Arizona" :( )
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    Q128H right-hand side outer bearing size?

    Anyone here happen to know (or have a dissassembled Q128H to hand) the size of the bearing on the right hand side, between the outer cover and the axle? If anyone knows (or can measure) it would allow me to order a new one and not disassemble until I got it. Thanks.
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    E-trike Aluminum vs steel frame

    Your faith in distance strangers is touching. Would you agree that Airbus SE are probably fairly competent and diligent engineers; working in a highly regulated industry and subject to intensely regulated and highly specified design and testing requirements? If so, read this(pdf) When those...
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    Ideas about charging batteries

    Do you ever park your bikes away from home?
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    The ultimate torque arm (For <2kW and standard axles)?

    Latest iteration: No drilling, screws or jubilee clips or extra tools required. One wrap-under plate (lighter blue lower image) and as many or few of the identical darker blues as your axle accommodates. Laser cut parts, bent with a couple of bits of scrap wood and a strong vice, heat...
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    2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

    No. If you follow the link to the bigger version, it also includes a ghost of the axle that shows the view is from the outside. If you're worried about the direction of rotation, imagine you are leaning over the bike from t'other side and looking at it upside down :) You'll have to imagine it...
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    2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

    I've had to shrink this using lossy compression in order to get it down to a size that will upload here (the original 15MB), which has made it rather small and fuzzy, but you can still see: The way the upper arm moves left relative to the lower. The ring being forced open as the load...
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    It's now Spring 2018.. Why haven't e-bikes gotten cheaper?

    BS.
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    2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

    Closed die forging -- hot or cold -- produces very desirable and repeatable grain structure: Which is why it is used for the manufacture of the highest stressed component in ICE engines, the gudgeon pins; and even 1-piece performance crankshafts: But die costs are huge and only make sense if...
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    The ultimate torque arm (For <2kW and standard axles)?

    Ah. Okay. I would have dismissed the thought except that for all the world, that looks like a tabbed torque washer under your domed nut. Three thoughts: The wrap-under layer is only 0.5mm thick and would fit around your dropout fine. It would replace 1 or two (or more) layers of the...
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    The ultimate torque arm (For <2kW and standard axles)?

    Is that a motor behind there? It looks like an ordinary wheel.
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    2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

    You miss my point. But what's new.
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    2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

    I was hoping that by modelling Justin's failed attempt, and showing that the results of the simulation produced similar results, I might demonstrate the efficacy of simulation testing. To be convincing, I need more accurate data than I can extract from pictures. (Due to the loss-y nature of the...
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    The ultimate torque arm (For <2kW and standard axles)?

    I did com up with a variation that might actually work for a fairly wide set of dropouts. (Sorry, couldn't be bothered to resize it for display here.) The layered spring is essentially the same, although I've adjusted the angle of the slot to allow the faces to better conform to small changes...
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    The ultimate torque arm (For <2kW and standard axles)?

    A link would have been nice. And do you realise that 0.015" is nearly 1/2 a millimeter? If your "fifteen thousandths of an inch clearance" means all around, then on a 12mm axle, that represents 3.45° of rotation in either direction. Or 2.2715° each way for a 14mm axle. Given a (relatively...
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    The ultimate torque arm (For <2kW and standard axles)?

    I briefly looked at the idea of trying to make a design (front or rear) that is universal enough to make it worth while having a batch made -- which significantly reduces the cost of having the parts laser or water cut -- and then heat treating and assembling and putting them up for sale. I...
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    2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

    Justin, Any chance you could post a dimensioned version of this design? I'd like to try and re-create your physical results in simulation, and the more accurate the model, the more likely I am to get something close. Thanks, Buk.
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    The ultimate torque arm (For <2kW and standard axles)?

    Having looked at the close-up pics of your axle mounts, I honestly don't think there would be any benefit to using the spring TA on your setup. With the axle being held by a very meaty steel pinch-clamp arrangement on the inboard end, there should be no axle acceleration -- nor even movement...
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    The ultimate torque arm (For <2kW and standard axles)?

    (The screen grab was truncate on the right; it's the same part.) Here for your delectation is an animation showing how a single layer distorts (exaggerated x20) as the axle rotates against it: The colors on the surface show the exaggerated displacements. Once the 12 layers are clamped...
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    2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

    Whenever I designed anything similar in the past -- a long time since -- the method for forming the bends was either fly-press (1-offs and prototypes) or a brake-press for production. At home, I probably clamp the plate to the back jaw of my vice, wind the front jaw open so that it was just...
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    The ultimate torque arm (For <2kW and standard axles)?

    What diameter are your motor axles and how much axle protrudes beyond the dropouts?
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    The ultimate torque arm (For <2kW and standard axles)?

    It does! Both faces to which the load boundary condition are being applied are clearly named. And that it what I'm up against. When you have loud-mouthed senior members claiming rocket science engineering skills, but who do not know how a nut and bolt works, what chance is there is my being...
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    The ultimate torque arm (For <2kW and standard axles)?

    Translation: "Technical generalist" -- Jack-the-lad-of-all-trades; master of none.
  24. B

    The ultimate torque arm (For <2kW and standard axles)?

    You mean you engineering wizards can't work that out from the information given. Come on Chalo, now's the time to step up and show everyone your prowess. It's a simple calculation; just get the units right.
  25. B

    The ultimate torque arm (For <2kW and standard axles)?

    No sh...ugar, Dad. (You cannot specify a torque, so you have to specify the force per unit area that would result from the torque acting on the face!) But that'll be over your head.
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