Bionx Electric Assist Wheelset

I am republishing this from Epinions as it is one of the most honest reviews I have come across about the Bionx Electric Conversion Wheel Sets.

To be honest I have considered adding one to my Recumbent to make riding more enjoyable as there are so many hills to climb here. However what has prevented me from taking the leap in addition to the high cost is there have been so few legitimate reviews of the product. I won’t be purchasing one anytime soon after reading this review due to their apparent lack of quality control. I can not imagine riding and having a wheel separate.

The real pros of the Bionx system to me are: low weight compared to no name competition, controller components allowing for “assist” mode instead of throttle acceleration, and ease of installation.

It’s my understanding Bionx is working with TREK to manufacturer 2 models of electric bicycles. Perhaps there is an option to purchase the product through Trek to get better service and warranty in the United States. It’s ridiculous ot have to send a part to Canada to get serviced in order to avoid voiding your warranty. Yes in many areas you can probably find a dealer, but in so many other areas you can not and thus Trek’s Dealer network would be a huge bonus.

For now I’ll keep looking. Too bad because I really like the idea of available electronic assist for pleasure riding and exercise.

————— User Review Below ———————–

Full Review: Bionx PL-350 Electric Bike Motor Kit

Main Review:

I strongly recommend buying this from a local dealer as you may be back several times for replacement parts under warranty.

Before this motor, I was commuting 10 miles to work via bike about once or twice a week, arriving soaking wet, needing to shower and it took about 30 min longer than taking the train (each way). As I aged, it seemed to take longer and longer to get to work (especially if I tried avoid knee pain). It was becoming a chore I did to loose weight and no longer much fun. I was down to twice a week tops (40 miles/ week).

I wanted to regain as much as possible that 1 hour per day as well as make it enjoyable enough to bike every single day and save more money on train fare.

I researched many options, but settled on the Bionx PL 350.

I wanted a solution that would allow me to park on the sidewalk right outside my building in downtown Chicago, which limited me to electric bicycles.

I narrowed it down to an add-on kit because I liked my current bike, even tho it is 20 years old. I felt buying a new bike was a waste of resources. I had spent a fair amount of time and money tweaking the bike to my liking (it is a Schwinn MOB).

Many electric bikes had smaller wheels and I am reluctant to go with smaller wheels because Chicago is not known for silky smooth streets and I have doubts about putting 2,000+ miles/year and a 250 lb load on a small bike.

I could not use a front-wheel kit because a decently powered motor would have simply ripped my front fork apart.

My biggest reason for going with the Bionx was simply its ability to be controlled by pedal power (off when not pedaling, on when pedaling over 3mph). It is exactly like normal biking except I now have “bionic” legs.

I did not want to deal with a toggle switch. In fact, I did not want anything on the handlebars to break if I crash or get stolen or simply malfunction due to exposure.

I also liked that the Bionx was the only motor narrow enough to allow for Disk Brakes (which my next bike would likely have). I chose the 350 because I needed the horsepower to get my 200 pounds and all my bags up to 20mph. From my research, I am pretty sure that a 24v 250hp motor would run out of steam long before I got my bike up to 20mph.

I chose the LiMn battery because much of this biking would be in the cold and I read that NiMH batteries do not perform well in the cold. LiMn also had the added benefit of “the more frequently you rec-charge them, the longer they will last” as opposed to NiMH where you needed to occasionally completely empty the battery in order to prolong its life and I did not want to deal with being in the middle of a ride and run out of battery power every week.

I chose the bag battery because I wanted to save time and hide the fact that I have a motor. It is an Arkel bag and it is a very nice bag (I actually already had that exact same bag). That big box on the frame screams “motor”. I would have to put that white box into a bag anyway in order to take it indoors, so why not have it in the bag all the time? Also, the bag concept allowed me to keep everything, including the controller better protected from vibrations and weather.
I keep the controller inside the bag on my rear rack. Before I start out to ride, I connect the motor to the battery, turn on the controller, set the assistance level to 2, zip up the bag and take off. I have seldom felt a need to see it again until after I arrive. Pushing the cord for the controller connector thru the hole in the front of the bag took a little effort, but was easy enough.

I had no problems installing it myself, and it came assembled in such a manner that the “notch” already was in the down position, so I did not have to fiddle with it.

I disabled the throttle. I tried to buy it without the throttle, but could not.

I never spent the time connecting the “brake to trigger regeneration” as it would be just one more thing to fiddle with. My battery never runs low enough to require the little regeneration it provides. If you had to go down hills a lot however, I can definitely see the benefit of connecting it, no braking required. However, there are not many hills in Chicago.

I DID have trouble finding the correct freewheel however. My bike uses a “compact drive” system where the front sprocket was 42 Teeth and the rear was 11 Teeth. Finding an 11T freewheel was a frustrating research project, until I finally found a vendor who kept them in stock at

My next project was to get a 46T front sproket because I kept wanting a higher gear as I pedaled (with the motor)

I used to spend 4 hours riding 40 miles per week and took any excuse not to ride that day.

Now I spend 6 hours riding 100 miles per week (same level of effort per hour) and hate having to take the train because it means being crowded and waiting and paying.

I used to average 11 to 15 mph.
Now I average 16 to 20 mph.

I used to start riding 1/2 way and taking the train 1/2 the first two times in April and only ride once a week to get my legs and rear end in shape.

Now I start riding the full stretch 5 days a week starting April 1st. I start out on level 4 assistance and in May, I will have worked my way down to level 2 on my way into work (to avoid excessive perspiration) and level 1 on my way back (to compensate for the extra resistance of the motor and extra weight).

I love the fact that I can now get to work 20 minutes faster while still getting the endorphins from exercising without feeling so exhausted that I need to shower and wait a day to recover.

I do wish that Bionx officially supported 3rd party batteries. Their asking price of $1,000 for this battery seems to be highway robbery. However there are sites out there that explain that as long as you buy your first battery from Bionx, you can use their battery controller chip and hook it up to a third party battery. This was another reason for wanting the bag battery as it seemed so much easier to re-wire and fit a 3rd party battery. Preferably a 12ah LiFePO4 battery from

For $100 more, will sell to you a Bionx approved version that has 25mph as the top limit (tho you sacrifice some torque). In some ways, I kinda wish I had that option, however I suspect my aging knees better appreciate that low-end torque assist in getting up to speed.

Be sure you double check that you received all the correct parts. The box we opened at the bike store included the 24 volt battery in the box. Everything else (including the charger) was for the 36 volt kit.

It has a tendancy to not turn off when I stop pedaling but ONLY downtown. I think if you only pedal short distances, the computer gets confused.

The system occasionally freezes up while biking. Basically it just stops helping you while you are pedaling, but works fine after you unplug the controller and plug it back in again.

It can spontaneously turned on while walking astride the bike across the street (no pedaling), but I just hit the brakes to get it under 3mph and the motor turns off.

I am contemplating connecting the regen brakes just to turn off the motor when it does occasionally stay on or turn on when I do not want it to.

I am figuring that counting saved train fares and value towards fitness it easily pays itself off after 3 years (with each 3rd party battery having a 1 year payoff).

The downside is the increased probability of being injured due to riding twice as often and the higher speeds. Last fall, I was doored for the first time after 30 years of using my bike as a primary means of transportation.

In summary, the system has more smarts than any other, but can still use a lot more improvement (most notable quality control with the rim and charger and motor).

It really was my only viable option for keeping my weight down and it is responsible for making me once again really enjoy biking to work every day.

Some useful links:
Here is the Bionx website

These guys seems to sell a lot of kits and I was hoping to avoid our 10% sales tax, however they never responded past my first email, so I just bought it from a local retailer (now I can get local support and I am supporting the local economy)

My local retailer (great service)

Besides having in stock an 11T freewheel, JV Bikes also carries a complete range of Bionx parts

I was VERY tempted to get a folding bike at the same time so I can more easily put it into our SUV on the occasions my wife picks me up with 3 kids in the back, but I decided to delay that expense until another time. As long as I get a 26″ folder, I can easily just transfer the wheel (or re-spoke it to a smaller wheel if I cannot find a 26″ folder I want to buy)

Here is everything you needed to know about bicycle terminology (which was very helpful to me understanding why the 11T became such an issue… apparently compact drive systems are not well supported in the aftermarket parts world)

Here is a very useful forum for Bionx

with links to manuals and codes and such

Here is a site that proclaims itself as “Everything you ever wanted to know about BionX”