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What hub motor gear set up do I have?

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    What hub motor gear set up do I have?

    I Installing a Aosom 1000w rear hub motor. Took off my 7 speed freewheel from my regular bike and it Click image for larger version

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ID:	47542 will not fit on my new hub motor NO threads. What gear set up do I have?

    Quite possible that is a front hub motor. I built my first ebike using the AOSOM rear hub, mine came with the freewheel already attached.Maybe someone else in here will know what to tell you to look for, good luck on your build.


      Daleh2 you could be right. The hub axle is just a lot longer than my axle on my regular fat bike. I am up for making a 2wd bike but I just don't see that axle sitting in my front fork. The axle stubs on my regular fat are just 1inch and a eighth long. I would have to make up 3/4 " in washer on one side just to tighten it up


        Just took a look at my old AOSOM hub motor and realized your picture is of the opposite side that the gears actually go on. At least thats the way mine is set up. The wires exit out of the non drive side. Also mine isn't for a fat bike, but you can lace these up in whatever rim you choose I believe. Take a good look at the other side.


          The wires of a hub motor always come out on the non-drive side.

          OP, please clarify the dropouts and total axle length of your hub motor (asked in post #12 in this thread together with a picture of both sides of the hub motor.

          The dropout measurement and total axle length (ideally stated in mm) is crucial information here.
          Last edited by commuter ebikes; 10-07-2017, 05:38 PM.


            If this is a front hub motor, that will be a good development for you because your freewheel or cassette won't have to compete with a hub motor for the limited space in the rear. The rear is crowded enough with the freehub/cassette or freewheel back there.

            If you end up running a front hub motor (using a fork with matching dropouts), you will sure be glad every time you change a flat in the rear.

            I am sorry to say that I think you have hosed your frame. I don't know how much you paid for it, but it looks like you need to start over with a straight, structurally sound, safe frame with the dropout size that you need. If you are attached to that frame, a local framebuilder could replace the chainstays and seat stays. You probably know now what sized dropouts that you need. It will almost certainly be cheaper to just start with a new frame, however; you will get to skip the step of aligning your dropouts. The good news is that steel frames are both strong and economical (and easily repaired!).

            Do you plan on running rim brakes or disc brakes?
            Last edited by commuter ebikes; 10-07-2017, 06:29 PM.


              I measured the total axle 190mm. power side 57mm ...... disc side 40mm


              • commuter ebikes
                commuter ebikes commented
                Editing a comment
                Confirmed front hub motor for disc brakes. Now you have total control over your choice of freehub and cassette, and changing a flat in the rear is as easy as it is on any pedal bike. I'm jealous! You can roll that bike into any bike shop in the world and they will perform any service required on the rear.

                Working with a front hub motor is more straightforward.
                Last edited by commuter ebikes; 10-07-2017, 06:56 PM.

              So the total axle length is 190mm. The dropouts of the axle in the drawing below are 190mm. Are yours 135 or 150mm?
              Click image for larger version  Name:	dropouts.PNG Views:	1 Size:	317.3 KB ID:	47598
              Last edited by commuter ebikes; 10-07-2017, 07:11 PM.


                If I were to measure the dropouts of an axle installed in a motor, I would use two people. Have one person hold out rulers up against the outer axle flats so that the rulers are parallel. The second person would measure the distance between the rulers.
                Last edited by commuter ebikes; 10-07-2017, 06:56 PM.


                  So it looks like one needs a steel QR fork in order to run a front hub motor. You probably have 135 or 150mm dropouts on the motor. This diagram sheds some light on this: Click image for larger version  Name:	p4pb13351708.jpg Views:	1 Size:	178.1 KB ID:	47604

                  You can't use a thru axle because you would not be able to get the axle in the holes.
                  Last edited by commuter ebikes; 10-07-2017, 07:09 PM.


                    Would you use a rigid fork or a suspension fork? In either case, you would need to know if your head tube is straight or tapered.

                    Here is an example of a straight head tube:

                    Click image for larger version  Name:	straight.PNG Views:	1 Size:	202.5 KB ID:	47606

                    This head tube calls for a 1 1/8" straight steerer tube.

                    If you had a 135mm dropout on your motor, you could use this: for a suspension fork or a Surly Moonlander fork for a rigid fork.
                    Last edited by commuter ebikes; 10-07-2017, 07:37 PM.


                      Here is an example of a tapered head tube:

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                      This head tube calls for a 1 1/8" 1 1/2" tapered steerer tube.

                      In this case, something like this would apply if the dropouts matched and it fit your tire:
                      Last edited by commuter ebikes; 10-07-2017, 07:34 PM.


                        Here is a steel 150mm QR fat bike fork:

                        These are kind of hard to find in QR.


                          You will also want to be be mindful whether to buy an ISO mount or post mount fork (for mounting your brake caliper).

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                          If you can't find the fork that fits your bike with your desired brake mounts (i.e. ISO or post mount), they make both "ISO to post mount" as well as "post to ISO mount" adapters. I use "ISO to post mount" adapters on all four of my bikes, and it isn't any kind of problem. It is very common to use some sort of adapter.
                          Last edited by commuter ebikes; 10-08-2017, 12:10 AM.


                            Of course all my problems were me being a dumb newbie. And the warehouse guy who sent me the wrong. Hub motor. YES it fit perfect on the front forks. Watched a couples of vids on the front hub install. Huh, Huh, Huh. but Thanks guys for all your knowledge here. I am ahead of zero now, but you could hear from me again. Thanks