No announcement yet.

Super commuter GT hardtail MTB cyclone build...

  • Filter
  • Time
  • Show
Clear All
new posts

    Super commuter GT hardtail MTB cyclone build...

    This is my first post here. I am nuggets

    I recently discovered electric bikes as a DIY thing. I decided that it would be fun to try one out. I've been reading and reading and reading....

    I eventually decided that I would build a mid drive bike, and that I would use the Cyclone kit. It seems to have the best bang for the buck... I was initially attracted to the BBSHD, but the cyclone won me over with its greater bang for the buck and it just seems like it will be more fun to install this kit.

    I didn't have the pile of broken e-bike parts, so I procured the required note from mommy...

    I acquired a nice entry level GT backwoods comp. It was the best deal I could find for a front suspension MTB with hydraulic brakes and mounting points for rack and fenders. All the equivalent bikes were at least $600, with the same level of components. This one ended up being $380, since performance took an additional 15% off for presidents day...

    Here is the victim:

    So far that is all I have purchased. So, here is my plan.

    I have a 10 mile each way commute. I am not capable of pedaling 25MPH, so I am adding some motor.

    Commuting mods:

    E-Bike mods.

    I plan to stiffen the motor mount like so:

    I'm still working on sorting out all of the bits and widgets I need to get to do the build. I want to use a cycle analyst, but have not decided which one. Suggestions are welcome.

    Did I miss anything? I haven't ordered anything yet, so if you want to tell me I am stupid to buy X, and want to suggest Y, then go ahead.

    Questions, comments, criticism welcome!
    Last edited by nuggets; 02-24-2017, 11:15 AM.

    Overall, things look good.

    My concern would be the size of your battery. Once you start riding, it is going to be hard to stay off the throttle.You will probably find yourself abusing that battery pack unless you have a good deal more self control than the rest of us :(

    Please check out the build howto at and ask a many questions as you want. The Cyclone 3kW was an awesome first build for me!



      Hey thanks funwithbikes!

      Here are the calculations I used for battery sizing...
      Battery: (assuming 20 watt-houts / mile, then a minimum of 400 WH is required for a 20 mile range.).

      I got the 20WH/mile from here:

      If we assume 80% charge, and 40% discharge to get 20 miles of range.
      Battery capacity would be 0.4 reserve + 0.2 not charged + 0.4 usable. 0.4 usable has to equal at least 400 WH.
      X * 0.4 = 400 ; X = 1000 WH
      @ 52V would require ~19.2AH

      I made paper models of the profile of the 52V 14,17, and 20ah batteries.
      The 52V 20AH pack is large enough, that it may not fit my bikes triangle at all.
      The 14 or 17ah batteries will fit.

      I also plan to pedal assist the bike since I can sneak exercise into my commute without any time cost that way.

      I suppose worst case, I will charge the battery at work, and then I can gas it all the way home!

      Does anyone know the dimensions of the cyclone controller?


        I agree small batteries can work. Just keep an eye on things as you performance expectations creep upwards :)

        See, for motor dimensions.

        Enjoy the build and enjoy your ride.


          I found that, but it does not give controller dimensions. I want to build a model of the controller box, so I can start mocking up its location on the bike.


            nuggets Here you go.

            Click image for larger version  Name:	IMG_1322.jpg Views:	1 Size:	334.7 KB ID:	28770
            Click image for larger version  Name:	IMG_1323.jpg Views:	1 Size:	232.7 KB ID:	28771
            Click image for larger version  Name:	IMG_1325.jpg Views:	1 Size:	268.1 KB ID:	28772
            Click image for larger version  Name:	IMG_1327.jpg Views:	1 Size:	237.3 KB ID:	28773
            Sorry about the DaveCad Drawings
            Last edited by funwithbikes; 02-24-2017, 01:06 PM.


              Wow! That's perfect, thank you.

              I just ordered the Cyclone kit, and the 17ah battery. As long as I am pedaling along, I should have enough range. I also ordered the lights, DC converter, rack, fenders, etc...

              I'm still trying to figure out which cycle analyst version to use. Luna's live chat person didn't know, so I sent an email.


                The cyclone controller does not have an adapter for the CA, but it is pretty easy to install if you know how to solder. And if you don't know... this is an excellent motivation to learn :)

                There is a generic set of instruction at . I could do a similar tutorial with specific instructions for the cyclone controller if you want.
                Last edited by funwithbikes; 02-24-2017, 02:10 PM.


                  funwithbikes, thanks for the help.

                  The dimension info is very useful.

                  I made models of the major components that will be living in the frame. It will all fit nicely. I'll have to design a box to hold all of it.


                    You are welcome.

                    Please hit us up with any more question you have.


                      So, some time has gone by...

                      Maybe you thought the thread was dead?

                      Spoiler alert: I rode it once...

                      I'll get back to this...

                      This kits not exactly bolt on(I knew this). Notice how the chain tensioner for the motor is. That's not my hack job, that's what comes with the kit. The motor mount that comes with the kit is not strong enough. Even running the bike with no load on the bench, there's significant flex.

                      This is my proof of concept tensioner prototype.

                      Works like so:

                      So, I put the throttle on the bike, and threw the battery and controller into the frame bag that came with the battery (that's the first pic). That was good enough to take it for a spin. Power wheelies in the lower gears. It's fast enough that it's kind of scary. Hydraulic disc brakes and a larger front rotor were good to have.

                      I didn't have a speedometer on the bike, but I'm guessing it will do about 40mph. I have a computer for it, but have not installed it yet.
                      Even though I didn't have the motor mount reinforced all the way, it did well. I rode it for a few miles. Mostly at full throttle. It doesn't have pedal assist installed, just throttle.

                      Then I tore it down again...


                        So here's the finished tensioner. It worked fine for the short shakedown ride.

                        So the bike went back on the bench after test riding so I could sort out the controller mount, battery mount, fenders, lights...

                        The first thing I did was to dissasemble the controller in order to add a cycle analyst connector and to lose all the extra connectors...

                        I got rid of the brake, cruise, PAS, and hardwired the 3 speed switch for max speed. I didn't buy the cyclone for low speed!

                        The bench test was a success. I setup the speedo, and the motor spins the wheel up to 52 MPH unloaded. Not bad.

                        Nothing is bolting on this bike, I even had to make little stay extenders for the rear fender.... And a few other fender mods... Haven't added the front fender yet.

                        Then I procrastinated on beefing up the motor mount by making some tiny spacers...

                        You can see where these go here, I have two stacked in this picture. I'll replace the upper bolts on the bar clamp with longer ones, and put a spacer under the bolts, then I will be able to mount a small plate to the clamp which will hold the cycle analyst and the headlight, and a switch or two.


                          So the motor mount that comes with this motor is a pathetic joke, it has multiple issues.

                          1. the mount will flex side to side.
                          2. the mount twists.
                          3. under power, the mount is pulled up to the frame, and crushes the rear brake line.
                          4. the mount falls down when you hit bumps.

                          I'm not going to use the cheesy giant hoseclamp and zip ties that come with the kit, just too hokey, and the zip ties are guaranteed to fail over time.

                          I held the brake and applied power, in order to test the mount.

                          So, I set out to beef up the mount.

                          I initially planned to do something like this, but I don't think that will help much with the fact that the mount twists under load.

                          After a lot of head scratching and false starts I laid out some lines and curves on some metal and started cutting.

                          I'm using 3/8th 7075 plate.

                          I used some tricks to match the curve to the motor...

                          Once I got the curves right, I laid out the mount holes.

                          And drilled them, and test fit them...

                          Then I added the holes for the mount brackets...

                          Then I made up a third plate from 1/4 plate. Then I test fit the mount again. Here you can see the weak and cheesy mount blocks that my plates are replacing. The two 3/8 plates, and one 1/4 plate were not quite thick enough, so I had to add a shim plate from 0.030" sheet. It already feels much stiffer.

                          The new motor mounts are close to complete, and they look like this.

                          I asked a guy I work with to bend me a small bracket from 0.090" plate. It will bolt onto my mounts, and then bolt to the black brackets. Then the motor will be highly resistant to twisting with respect to the bottom bracket. Here it is mocked up.

                          I'll drill and tap the mount plates from this direction.

                          More to come... But no work for a week...

                          I do have one question.

                          Does anyone know the resistance of the shunt in the cyclone controller? My multimeters are not sensitive enough to measure it. I could use the info to set up the cycle analyst.


                            Back to the saga of the massively over-powered homebuilt e-bike project.
                            Mount progress....

                            I used this bent piece of 0.90 aluminum to tie the motor mount to the bottom bracket mount.

                            And I added these braces.

                            Another angle...

                            This whole thing is put together with a collection of random fasteners, so I will have to buy the correct fasteners.
                            Here it is mounted on the bike. I had to change all the fasteners on the sprocket side to low head socket screws since the hex heads intererfered with the sprocket and the chain.

                            Once everything spun well without power, I turned it on and throttled up. Previously, the mount would twist just spinning the wheel under no load. It doesn't do that anymore. I used the brake to hold the wheel, and applied power. The motor twists... WTF?!

                            I look at it some more. It's not the mount. As it goes when you strengthen one thing, you find the next weak thing. It turns out the mount does not twist anymore, it's actually twisting the bike frame. The cycle analyst says that I put 100 amps into the motor to do this....

                            The good news is that the mount is strong enough. I'll see how long the frame holds up...


                            I've got to add a bracket to tie the motor into the down tube so that the motor won't rotate down when I hit bumps, and so the motor won't rotate up when it pulls on the chain. Once that is built, I'll finish all the motor mount parts, and be done with the motor install.


                              An update on my install.

                              I've pretty much finished the motor mount.

                              I made this plastic block to prevent the motor rotating upward under power.

                              And I made this strap to prevent the motor rotating down when hitting bumps.

                              I've also built my controller mount.

                              I replaced the rack bracket with the mount. I think it is pretty well integrated in that spot. It has good airflow, and the wiring passes through between the seat stays, so it will help prevent the wiring from being too eye catching.

                              Yes, I am missing fasteners. I didn't have enough M5 hardware, so I will have to order some. Once I am finished with all the prototyping, then I will order hardware.

                              Also, I learned a lesson about battery safety. I was mocking up the battery location in the triangle when the charge connector brushed against the sprocket. There was a tremendous flash, and the charge connector got burnt, and one of the sprocket teeth got ruined. I should be able to save the sprocket with some careful file work. Now the battery connectors are bagged, and I have to order new XT60 connectors.

                              Notice the tooth with the gold material from the connector welded to it.