E-Bike Conversions May 22, 2014 Mark D Larsen

Pedal Pusher (click to enlarge)

I am pleased to announce that we now have two more electric vehicles in our household. Well... okay... maybe “vehicle” is too strong a noun. To be more accurate: I have managed to convert our bicycles... into e-bikes.

I have always enjoyed bicycles, but would be the first to admit that I am a different breed than pro-cyclists. For me, pedaling along is not so much a “sport” as a fun, practical mode of transportation. Like all kids, I grew up riding bikes around my neighborhood, but I came to actually depend upon them during the two years that I lived in Argentina, many decades ago. Biking was my principal means of getting around, and because every couple of months I was transferred to different cities, I decided to buy a folding mini-bike that I could load into the buses’ cargo hold along with my suitcase. On the left below is a photo of that bike, and you can see that it had a “banana” seat, a backrest, and “easy-rider” handlebars. I quickly learned to really enjoy the “heady” sensation of toodling along in that position, instead of hunched over the handlebars like on more traditional bikes.

Know when to fold ‘em (click to enlarge)

Easy Rider (click to enlarge)

For this reason, when Tamara and I decided to buy a couple of bicycles a few years ago, I couldn’t resist opting for a similar model: a Giant Revive DX semi-recumbent, shown above on the right. Yes, with such a massive frame, it is a heavy bike, but the way it swoops through curves is addictive, almost as though you were riding a skateboard. It also boasts lots of bells-and-whistles: enclosed chain guard, electronic speedometer and odometer, disc brakes front and rear, spoke protectors, integrated bike rack, an in-hub 7-speed Shimano Nexus transmission, adjustable seat, backrest, and handlebars to fit practically any rider, short or tall. It is truly a shame that Giant no longer sells the model, because its ergonomic styling even won accolades from the Institute for Human Centered Design.

As for Tamara, she didn’t want such an odd, exotic-looking pony, so instead opted for a more traditional bike: a Trek “crossover” with a mountain-bike frame, but street-bike seat and handlebars, with the same Shimano Nexus transmission. Her bike is in the photo on the left below, and on the right you can see how the two horses compare in size and shape.

Starring Trek (click to enlarge)

Yang and Yin (click to enlarge)

A few years after buying these bikes, while visiting Tamara’s family near Sacramento, we decided to stop by Davis Electric to check out the now-extinct ZENN neighborhood electric vehicle (NEV). We found that the store also sold a wide variety of electric scooters and bikes. The latter were rather heavy, cumbersome Clydesdales, because lighter lithium batteries had not yet entered the market. Nonetheless, we were intrigued by how effortless and fun it was to ride them. Somewhat like a moped, they had a throttle near a handgrip which you pushed with your thumb to power the electric motor. Below on the left is Tamara with the model that she test pedaled. Truth be told, she came away thinking that she had made a mistake buying her Trek and wished she had one of those e-bikes instead.

at Davis Electric (click to enlarge)

at EVS 26 Ride-n-Drive (click to enlarge)

Still later, shortly after taking delivery of my Leaf, I decided to go to Los Angeles to take advantage of “public day” at EVS 26 to test drive other electric cars. I was able to take a spin in the Focus EV, the iMiEV, and the Coda, but I also saw that Pete’s Electric Bikes was at the Ride-n-Drive event, allowing attendees to take demo rides around the plaza. Naturally, I took advantage, as shown above on the right, and was amazed to experience electric pedal-assist for the first time. It is a liberating, gleeful feeling to push down on the pedals and suddenly feel like your legs are stronger than a those of a Tour de France competitor.

Now I was torn. I wanted an e-bike too, but was loathe to give up my cool semi-recumbent. Still, I researched the models and prices of the e-bikes available. The prices were frankly shocking, as much as 3 to 6 times the price that we had paid for the Trek and Revive. I then started looking at possible conversion kits. The prices were more reasonable, but many outfits were facing bottlenecks to supply lithium battery packs. Moreover, most of the kits consisted of motorized hubs. I wasn’t sold on that solution, especially for the rear wheels, because it would mean getting rid of our Nexus tranmissions.

I then discovered that there was a time when Giant also sold an electric version of my Revive, called the Spirit. What really caught my eye with this version was that it used a Panasonic mid-drive, rather than hub motors. I tried searching for similar Panasonic mid-drives, but could only find models that worked with dedicated e-bike frames, custom designed to accommodate the motor. Then I hit paydirt at Lectric-Cycles in Tempe, AZ. They sell similar mid-drive conversion kits from Bafang in China that will fit practically any bicycle, and that boast both throttles and multiple levels of pedal-assist. I called their store to ask questions about the drives. The rep asked me to describe our bikes and the kind of riding we do. He then recommended that we buy the smallest, least expensive 350w kit, because it would more than suffice for our needs. The larger 500w and 750w models would be overkill, only appropriate for pro-cyclists who do very serious mountain climbing, and would likely even damage our Nexus gears. I appreciated his candor, honesty, and experience, and subsequently ordered two of the 350w kits and two 36V 14.5A batteries.

The mid-drive kits arrived a few days later. I unpacked the boxes, examined all the parts, took a deep breath, and started the challenge of installing the kits. In truth... it was harder than I anticipated. I quickly discovered that I needed specialized bicycle tools to remove the crankshafts and bottom bracket locknuts. I also needed a good chain tool to break and reassemble the chains to accommodate the new front sprockets on the mid-drives. Thank goodness I already had metric sets of wrenches, sockets, and especially hex keys. I suppose that the most confusing task was to remember what bolts, screws, hex nuts, brake and gear cables I had removed, and in what order, so that I could reinstall them correctly after the motors were mounted. Several times... I screwed up. Literally.

Even still, Tamara's Trek was easier to convert than my Revive, precisely because it has a more traditional frame. You can see the results in the photos below:

Tech Trek left (click to enlarge)

Tech Trek right (click to enlarge)

I had hoped to retain all my bike’s original components, but discovered that it just wasn’t possible. For example, because the new sprocket was about a half-inch wider than before, the chain tracked a slightly wider angle to the back. I therefore had to completely remove two small sprockets than had channeled the chain through its enclosed guard, and then discard that guard entirely. Now the chain is shorter and exposed to the elements. I also had to remove the Revive's spoke protectors and substitute its front speedometer sensor with the new one on the back. To mount the new display, I even had to get out my dremel and cut pieces out of the wide center of the Revive’s handlebars so that I could pass the pre-wired components through larger holes. Below on the left you can see how the new readout is installed where the original used to be. You can also see on the right that I had to mount the mid-drive at a lower angle than on the Trek because of the Revive’s oddly shaped frame.

turned on (click to enlarge)

the low down (click to enlarge)

Below is the result of my efforts. Without all its original doohickeys, the Giant Revive looks more spartan than before, but the mid-drive has actually boosted its fun factor to an even higher level.

Revived Revive left (click to enlarge)

Revived Revive right (click to enlarge)

Ah... but the fun doesn’t stop there! Since Tamara and I now plan to spend more time biking around our community, we certainly can’t leave our little girl behind. I therefore bought a collapsible DoggyRide mini trailer to tow her behind me. ‘Tisa was very wary of it at first, but after a few days she settled down enough to let me put her in it, strap her in with her harness, and give her a short ride around our subdivision. Once she realized that it was similar to riding in her car seat, and that she could sniff and savor every scent we passed, she loved the experience. Now, every time she follows me out to the garage, she makes a beeline for her “cart,” as though begging me to put her in it and take her for another ride. Below are a couple of photos of Princess Petisa in her royal carriage. There is also a very short movie of my mid-drive in action.

Wheeler Dealer (click to enlarge)	Top Notch (click to enlarge)
Traction Action (click to play a short MP4 movie)

So what’s the next step... er... pedal? Glad you asked! We already have a bike rack for the Trek and Revive that attaches to our Subaru’s trailer hitch. Just last night I ordered an TorkLift EcoHitch so that we can also use the rack with the Leaf. I’ll probably post another page about that hitch after installing it. We then plan to visit the numerous bike trails within the Leaf's range in our area. Come to think of it, since our bikes are now electric, we can tell passersby that they are our range-extender —instead of a fossil fueled REx or Voltec generator.