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    New to EBikes

    Im new to this area of biking and really much biking in general. Im looking at buying a rear hub unit and need to know what a freewheel is. There is an option to buy a freewheel on the purchase order and Im old so I know what pedals and tires are etc. but the term "freewheel" has me confused. I am putting this motor on a speialized frame for general in town riding on hard surfaces. It is not a single speed bike but I have no idea hw many gears it has. I probably only used 3 or 4.

    #2
    Freewheel is like a cassette but the ratcheting mechanism is built into the sprocket portion instead of the hub

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      #4
      I purchased a 750 watt motor kit for rear wheel, I hooked everything up and tried the motor,immediately the rear wheel jumped out of the dropouts and sheared the wires off. Had to practically rebuild the motor and I bought two torque arms. Put them on and rode about two miles before the wheel jumped out again stopping me right now. Survived and took everything apart and put the torque arms on a different way , turned the bike right side up pressed the throttle and the rear wheel jumped out again. Where can I find directions for torque arm installation and what should the torque specs be for the wheel nuts?

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        #5
        Maybe take a pic of how you have it?

        You sure the dropouts are not damaged from spinning out?

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          #6
          Here is the drop out. Loose fitting and the same on the other side. Pretty sloppy

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            #7
            To me, that looks like a pretty big gap between the axle flat and the inside of the rear dropout. The axle flats should sit pretty close to flush inside the dropouts.

            What is the diameter of that axle? What is the distance between the axle flats? 10.0mm?

            What material did you say the frame is made out of? If you can, show us a picture of the bare dropouts in the frame (i.e. without the motor in there). I want to see if the axle flat sides of the dropouts are parallel (as opposed to being spread out, deformed by a rotating axle).

            If it is a steel frame, you can bend it back and use securely attached torque plates or torque arms. Securely attached torque plates or torque arms will definitely hold the axle in place.

            If it is the case that you did damage your frame, don’t feel badly because I have done that.

            Steel frames can usually be repaired.
            Last edited by commuter ebikes; 07-19-2018, 08:43 PM.

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              #8
              Also try to upload a picture of the outside cross section of the axle. In the photo, it looks like a circle.

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                #9
                FYI I tried “universal” torque arms, but I never got a nice tight fit until I made custom torque plates specifically for my bike.

                For the money I spent on universal torque arms, I could have just made my own torque plates fit to my bike. It did take many hours of cutting, drilling and filing, though, even after the machine shop made the plate with the D-hole in it, leaving me to drill the mounting holes, file for a tight fit, and trim off the unnecessary material.

                If you use regenerative braking, torque ARMS are not as good as torque PLATES because people decide where to clamp the torque arm to the seat stay based on stresses applied when the motor is propelling the bike forward. With regen, the torque is in the opposite direction, pulling on the hose clamps securing the torque arm to the seat stay.

                A torque arm is designed to rotate the arm into the seat stay and transmit force into the frame. This does not happen when the axle is rotating backwards. I suppose many people would argue that hose clamps can handle it, but I’m pretty sure the engineers who designed hose clamps did not design them for such oscillation and resulting metal fatigue.
                Last edited by commuter ebikes; 07-19-2018, 09:12 PM.

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                  #10
                  Yeah that's loose for sure.
                  I would use a different frame.
                  Maybe figuring out some way to integrate a shim into the torque arm would also be an option, so the shim extends not only through the torque arm which would affix it in position but also through the dropout itself. .

                  Or maybe you could pull the dropout a little tighter using a U Joint press, a few models out there only cost like 30 bucks
                  Click image for larger version  Name:	15001.gif Views:	1 Size:	66.1 KB ID:	69754

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                    #11
                    Originally posted by paxtana View Post
                    Yeah that's loose for sure.
                    I would use a different frame.
                    Maybe figuring out some way to integrate a shim into the torque arm would also be an option, so the shim extends not only through the torque arm which would affix it in position but also through the dropout itself. .

                    Or maybe you could pull the dropout a little tighter using a U Joint press, a few models out there only cost like 30 bucks
                    How have I survived this long without a U-Joint press? I bought this one https://www.autobodytoolmart.com/otc...8-p-15001.aspx.
                    Last edited by commuter ebikes; 07-19-2018, 09:50 PM.

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                      #12
                      Fair warning I have not confirmed this will work, it is more of a guess..

                      That said, I see no reason why it would not work, as long as you got a breaker bar for whatever wrench you are using.

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                        #13
                        I am still wondering if this is a steel or aluminum frame we are looking at.

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                          #14
                          The drop outs are aluminum. I have a threaded hole just up the frame from the drop out. It had been used to support a carrier. I found that the torque arm when disassembled could be bolted into this hole and secure the axle. There is a fair amount of play however. I may find myself another frame if this doesn’t work. I’m a little apprehensive of going more than a few miles per hour under power till I see if this works. No fun stopping on a dime when the wheel pops out.

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                            #15
                            Aluminum is not my favorite material for an ebike frame because you don’t need the weight savings when you have a motor.

                            Make sure that your dropouts are not spread out (caused by a rotating axle). I would not attempt to repair a damaged aluminum drop out.

                            I have seen torque arms that have one hole in them to bolt on to the frame. If it is attached securely with no movement, that ought to work for up to 750W.

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