Easy Electric Bike Conversion Kit Installation




Introduction: Easy Electric Bike Conversion Kit Installation

An electric bike (e-bike) conversion kit is a great way to breathe new life into an old, neglected bike. After spending some time researching the two main types of kits available (mid-drive and hub motors), I finally decided on a Golden Motor Magic Pie v5 hub motor.

This kit replaces the bike's rear wheel and includes a throttle as well as new brakes that will cut power to the motor while braking. Having never worked on bikes before, it was certainly a bit stressful at first, but in the end, it turned out to be much easier than I had expected and only took 2-3 hours to complete.

Step 1: Selecting a Battery Pack

Selecting a battery pack can be a bit confusing. There are several different styles to choose from, cell manufacturers, voltages, and amp-hour ratings. The motor will specify the voltage range that is allowed, and it is important to get a battery pack that falls within this range. A pack's amp-hour (ah) rating will dictate how far it can go on battery power on a single charge. And speaking of charge, a good battery charger is also important, though most battery packs will come with one (or at least recommend one).

Panasonic and Samsung seemed to be pretty popular choices for high-quality cells, so in the end, I decided to go with a 52V 13.5ah Panasonic NCRB bottle battery pack. It installs in the drink bottle mount on the bike's frame, so it's a little less noticeable other than it looks like I drink a lot of water.

Step 2: Removing the Rear Wheel

The first step to installing the hub motor was to remove the rear wheel. I started by loosening the brake cable and then the wheel's quick release lever. Then it was just a matter of holding down the rear derailleur while lifting up on the wheel to remove it.

Step 3: Removing the Existing Freewheel

The Magic Pie kit recommended a 7-speed freewheel, and since my bike came with one, I used a freewheel remover tool and a 1" socket to remove it.

Step 4: Removing the Existing Tube and Tire

Since I planned to reuse my existing tube and tire, I deflated the tire and used a set of tire levers from a small bike kit to pop the tire off.

Step 5: Installing the Tire and Freewheel

After transferring the tube and tire to the new wheel, I installed my old freewheel onto the Magic Pie hub, being sure to use the included washer as a spacer to prevent the freewheel from binding. (Note that to get the freewheel back off the motor, the hole through the freewheel remover tool must be widened with a 9/16″ drill bit as the axle is fairly thick.)

Step 6: Installing the New Wheel and Torque Arm

The next step was to put the wheel back on the bike. I added two of the included washers to the axle on the freewheel side — these prevent the freewheel from binding on the dropout. I also added a lock-washer on the other side and then placed the wheel back on the bike. Once the wheel was fully seated in the dropout, I used the remaining lock-washer and secured it with the axle nut on the outside of the dropout.

On the other side, I attached a universal torque arm for additional safety. I then added the remaining axle nut and tightened both sides down very securely with a 7/8" socket wrench.

Step 7: Running Wires

There were several wires that need to be run along the frame of the bike, so I just took my time and secured them with zip-ties.

To avoid cutting the wire to the battery, I simply looped it around the seat tube. I then connected it directly to the battery mount which installed easily in the holes for a water bottle holder.

Step 8: Installing the Display and Controls

With the wiring mostly complete, I removed the handlebar grips using my air compressor to blow air inside the grip. Then I loosened and removed the shifters and existing brakes.

Next, I mounted the display to the center of the handlebars. On the left handlebar, I installed the included throttle and e-brake (cuts power to motor when braking), as well as the controls for the display. Since space was a little tight, I decided to not re-install the 3-speed shifter for the crankset. On the right handlebar, I installed the cruise control switch and the remaining e-brake as well as the 7-speed shifter that came with my bike.

Step 9: Completing the Installation

After reinstalling both grips, reconnecting all the brake cables, and performing a little more cable management, it was finally complete!

A quick test ride proved that this motor and battery combination are pretty amazing! I was able to easily reach 30 MPH on throttle alone, and the acceleration is enough to cause you to pop a wheelie if you’re leaning back. I can definitely say that it is more than enough power for me at 170 lbs.

Unfortunately, it needs to be reined in a bit to comply with local laws (and the wife). These laws tend to vary quite a lot by location, so be sure to do some research before shelling out cash on a souped up e-bike.

Step 10: Programming the Magic Pie Motor

In order to adjust the motor’s settings, I purchased a USB programming cable. This uses the plug from the motor that the display unit normally connects to and has a USB connection on the other end that connects to a Windows PC.

[Note that there is an option to use a Bluetooth adapter with an Android app, but several people (including myself) have currently been unable to get the app to work properly.]

Once I installed the appropriate drivers on my PC, all that was left was to plug the cable into the computer and run the configuration software. There are several options that can be adjusted including max speed, acceleration, and regenerative braking. After a few tweaks to the motor’s settings, I had everything running within limits and the acceleration was nice and smooth.

Step 11: Parts and Tools

Step 12: Conclusions

I wasn’t sure how hard it would be to do the conversion, especially since I had never done any real work on a bicycle before, but it turned out to be quite easy. Certainly not as easy as buying a new electric bike, but that would have also cost a good bit more for similar features, and this way I was able to reuse my current bike. So far the results have been great, and it's certainly a lot more fun to ride around!

Note that since there are several types of electric bike kits and many different bike designs, be sure to follow the directions from whichever kit you purchase carefully!

Bicycle Contest 2016

Second Prize in the
Bicycle Contest 2016

Make it Move Contest 2016

Runner Up in the
Make it Move Contest 2016



    • Metalworking Contest

      Metalworking Contest
    • Water Contest

      Water Contest
    • Fix It! Contest

      Fix It! Contest

    33 Discussions

    Hi, I built one of these recently from a kit. One valuable thing I wish someone had told me in advance was to get a torque arm. The power from the larger motors was to much for the frame that I had fitted it to originally, ended up chewing through the rear hub. The kit I ordered didn't come with one or have any mention of it. Wish I had seen this instructible first. Excellent job.

    Hey, I purchased and assembled a adult tricycle for a family member who had a stroke.

    She enjoys the mobility, even though she powers along with one leg(!) but inclines are a bugger! Especially because of the seating position with the pedals in front of the hips.

    I've been trying to find something that would work.

    To your knowledge, would something like this work on a trike, which has the chain drive in the middle of the rear axle?

    Has anyone ever installed something like this on a front wheel instead?

    Lettuce know please folks?


    3 replies

    There are smaller (diameter wheel) versions of this motor. However, there was also a recent Indiegogo & Kickstarter campaign for the 'Liberty Trike" which sounds like it might be what you're after: http://www.libertytrike.com/

    My wife ordered one to experiment with for running errands, and it should be here in a week.

    There are also front wheel kits that you could use - pretty much identical to the rear wheel, only not need to transfer the gears etc over and should be suitable for the trike with no modifications. 99% of this 'ible is a match, really. I've seen loads of them on ebay ranging from 250W through to 1000W, some batteries included, others not. Possibly the Magic Pie might have a front wheel version, I don't know. Hope that helps.

    Years ago (back in the 90's) I converted a bike to electric assist
    by rigging an old Toyota fan motor to the rear wheel of my bike with a 2" hard rubber wheel glued to the motor shaft, that gripped the wheel and spun it. It was held in
    place on the top of the tire by a spring-loaded door hinge and some
    hose clamps. I ran some heavy gauge wire from the battery to the motor, with a voltage limiter/circuit breaker mounted inline, and a simple rocker switch on one of the grips. For power, I used a motorcycle battery mounted on the rear bike rack. It would carry me for about 6 hours at around 15 mph, or it would help me with the hills. I could disengage the motor at any time and ride without it. The total cost was about $50, and it was a breeze to build and install. Lots of fun, too!

    3 replies

    I have a honda fan that needed to be replaced if I can get that working again do you think I could do the same thing? I'd have to find a battery and rig a way to recharge it.

    You should publish an Instructable on that!

    Haha! Awesome! It sounds similar to the Rubbee friction motors: http://www.rubbee.co.uk/ -- which is yet another type of e-bike motor and arguably the easiest to install, though a bit less powerful.

    Nice instructable but why is that kit so expensive? I got my kit for way less here and it goes 30mph and 25 miles on a charge!

    1 reply

    The cost of the kit that you linked seems to be within ~$50-60 of the Magic Pie 4 or 5 kits if you want the LCD display. However, one feature the MP kits have is that the controller is integrated into the hub as well as being a 1500w (vs 1000w) sine-wave controller. I personally liked not having to find a place to mount the controller, so I thought it was worth it.

    The kit I linked is also sold by a US company, so I felt a little better dealing with them vs. having to ship the motor or battery (which can be quite expensive) back to China or another country.

    yeah, I'm not spending $600 plus on what amounts to half a golf cart. until someone makes a complete kit for under $200 I'm sticking with the bike engine kits.

    Very cool 'how much $ for this kit ? & how far can you go on a single charge ? Jimmie R

    Very nice instructable.

    Around here in Europe, this kind of e-assist (throttle) goes legally as motor bike. This requires you to wear a bike helmet and bike license plates. In contrast are the so called pedelecs that assist up to 25km/h or 15mph, no license or helmet required but a bicycle helmet makes sense anyway. The faster ones up to 35km/h or 22mph also require license plates and helmets. (what type of helmet required is country specific. In Switzerland, a bicycle helmet is ok, in Italy for example you need to wear a bike helmet...)

    But what's common to all pedelecs: They only assist, when you pedal. This makes sense and seems to be more intuitive on a bicycle. The more torque on the pedal, the more power the motor brings in additionally. I own such a bicycle with a Bosch system and i really like it. It has 5 levels of assistance. From Eco which barely eliminates the weight of the bicycle to Turbo, where you only need to turn the pedals with almost no torque of your own.

    I'm not affiliated with Bosch by the way. (I only like their system, because of it's high development level and their warranties on the drive and battery pack. And of course, because theoretically there are ways to trick the speed limits above... voiding the warranty and being illegal of course)

    I also wanted to do such a conversion a couple years back. But given the legal stuff and the price of such a conversion, i put it on hold. Then a friend bought such a offroad e-bike and let me test it. Three days later, i had my own... (at around 3000$)

    1 reply

    Yeah, the Bosch kits are really nice. They're similar in style to the Bafang BBS02 mid-drive systems which I debated getting as well.

    The Magic Pie does have an optional Pedelec Cable and the LCD display unit has controls for 5 levels of pedal assist though the sensor is not 'torque sensing'.

    Really nice Instructable...but, in the video where you put the lock washer on the first side of the wheel, you are doing that incorrectly. The 'tongue' part of the lock washer must be placed inside the solid hole in the side of the bicycle, not where you slide the bicycle tire into. Doing it the way you showed makes it possible for the tire to come off the bike. Of course with the added safety of the torque arm that you added, it would be highly unlikely that it would come off. Just mentioning in case someone doesn't have the added safety features you have...

    3 replies

    Are you referring to step #6? Unfortunately there were no directions from Golden Motors as to how to install those and there was no other orientation that that would fit properly that I could find without filing them down. Do you have a photo?

    Actually after looking at your video more closely, it looks like your bike does not have the slot or the slot is behind the axle. I was referring to 1:10 of the video. I will add a picture of what I was looking for. Sorry if your bike is not built in this fashion...so many different styles now...and sorry for being so late, I work really long hours and left shortly after posting. Again, great Instructable! This is a picture I grabbed from Google Images...


    No problem, it's certainly a valid point, and I spent a while trying to figure it out. But yeah, there are no notches for it on my frame for the tab/tongue to fit in. The axle and washer are actually flat on 2 sides, so it can only fit how I showed or pointed up - and that would have caused it to not sit flush. The way it's oriented here should at least keep the motor from ever trying to rotate the axle in the drop-out.