Our last bike tour (fall of 2022) was very hilly, and there were a few places where I (Jennifer) had to get off the bike and push it up the hill. One hill in particular seemed very dangerous, because there was a lot of traffic and there really wasn’t a good place on the side of the road to push the bicycle. So I started thinking about adding an electric motor to my existing recumbent bicycle, to convert it into an e-bike. I guess I’m a slow thinker… in June of 2025 I finally decided to purchase an e-bike conversion kit, and now my bike has a small electric motor assist! Here are some notes and photos.
I bought the e-bike conversion kit from Grin Technologies in Vancouver, BC. It consisted of:
- A Bafang G311 front hub motor built into a new front wheel
- A Grin V6 torque arm to transfer the motor torque up the front fork
- A Grin LiGo battery with three 99 watt-hour modules in parallel, a rail to mount it on, and a battery charger
- A Grin Baserunner Z9 V6 motor controller, which takes the DC power from the battery and converts it to AC for the motor, and modulates the current to control the motor speed
- A pedal cadence sensor from Grin with an up/down button to control the amount of assistance
- A thumb-operated throttle
- A Grin Cycle Analyst V3 device, which takes the throttle, button, and pedal sensor input and converts it to a single throttle signal for the motor controller. It also has a screen where you can monitor the battery, your speed, and all kinds of other information, as well as a very flexible settings menu
- Cables and mounts to connect all of this to the bicycle and the parts to each other.
I also got a few other parts from other sources:
- A BikeSpark BKS-G5 Auto-Sensing Rear Light — the bike had a dynamo in the front wheel that powered front and rear lights, but it’s not the same voltage as the e-bike battery, so the old lights wouldn’t work. The new rear light senses when you brake and flashes.
- A second Terra Cycle Cockpit Mini-T accessory mount for all of the e-bike controls
- A mount that I can attach a front light to (I have a tiny flasher for emergencies)
- Some new aluminum Planet Bike Cascadia fenders (this wasn’t technically part of the e-bike conversion, but my old fenders were being held together by duct tape, and I installed them at the same time as I did the other work)
The first thing I did when I was ready to install the kit was to verify it would work: I put the new front wheel on the bike, and hooked up to the battery, controller, Cycle Analyst, and thumb throttle. I pushed the throttle and whee! The wheel turned!
Then it was a matter of getting everything mounted on the bicycle and connected together. There were a few snags:
- I had ordered a torque arm that didn’t fit on my bicycle, so I had to get a different one, and mount it in a way that didn’t match the instructions for that torque arm, because the Bafang motor is strange (contact me if you want details).
- It took me several tries to get the disk brake rotor mounted on the wheel so that the wheel would spin without the rotor or the screws rubbing on the fork or the disk brake mount.
- Fender installation is always a pain (even when replacing fenders by similar ones — the struts were not in the right places or the right lengths).
- I had to cut the wires to my dynamo generator-powered lights to get them off the bike
- My bike fell off the stand a few times, and one of the times it bent the big chainring on the front. I was able to straighten it out by following instructions from the Late Great Sheldon Brown (I hope his web site never goes away).
- I managed to stab myself in my hand and bruise a nearby joint with some needlenose pliers while wrestling with a part, and had to go to the urgent care to get it cleaned out. The puncture wound healed well, thankfully; the joint is still sore two weeks later, but is healing.
The end product was a working e-bike!
Some notes:
- I’m currently mainly using it on hills and to get going from a dead stop (especially when crossing or turning into traffic) — at least so far — I have only had it for a short time.
- The Cycle Analyst is very flexible on the settings. You can set a maximum speed, how many levels of assistance you want to go with the pedal cadence sensor (currently I am using 8, after starting with 5 levels and finding I wanted a finer control), what to display on the main screen, whether to display other information screens when moving or stopped, and many other things.
- I’m not using anywhere near the maximum power the motor is capable of. The most I’ve used is level 3 of 8 going up a hill (but I haven’t tried it loaded up with panniers like on a bike tour yet).
- At level 1 (as I currently have it set up), the motor pulls about 80 watts. Since I have about 300 watt-hours in my battery pack, it should go for a bit under 4 hours of riding at that assistance level. Level 2 draws twice the power, so it would only last about 2 hours at that level, and so on. Since I’m not using the assist when I’m riding on the flat or downhill, this seems like sufficient battery for most rides.
- I could get another couple of battery modules if I needed more power (for a tour, maybe?), but the rail I purchased can only hold either a 2- or 3-module battery pack.
- The conversion added 14 pounds to the weight of the bike, including 4.6 pounds for the 3-module battery.
- When one person in a group gets an e-bike, everyone else has trouble keeping up… Zach is now considering converting his bicycle as well.