BionX and Pedal Assist Systems and Cargo Bikes -Q & A


HOW DOES THE BIONX SYSTEM WORK AND WHAT DOES IT FEEL LIKE WHEN RIDING? First and foremost all BionX systems are a pedal assist type system.  This means the system senses that you are pedaling and based on the power assistance setting you choose, assists your effort.  Realize this does not require the use of a throttle of any kind.  All you have to do is ride the bike just like a regular bike and have a little (or a lot of) extra help. There are two important elements of a pedal assist system.  A) a torque sensor and B) program software that manages the power output based on input variables.  The BionX systems exceed all other pedal assist systems on the market in my opinion not because of shear power in climbing hills, or forward speed, or large battery run the BionX systems generally have none of these as superlatives.  Where the system really shines is the programming that makes the system easy to use, and enjoyable to ride.  Some pedal assist systems are kind of herky-jerky power on...power off...power on kind of feel.  The BionX systems will have more subtle assistance on the lower power setting, but can really get you going when you need it. The advantage of a torque sensor is that it can measure the rider power output...and based on the choice of what power setting the rider has inputted, the system will assist.  The BionX systems have 4 assistance levels.  Power level 1 is barely noticeable...used when you want to extend the charge of the battery or riding on level ground at a casual pace-perhaps making your e-assist cargo bike feel like just a regular cargo bike…meaning enough assistance is given to cancel out the additional 18 pounds of weight from the battery and motor on flat terrain.  Assistance level 2 is more than enough to cancel out the additional weight that the battery and motor put on the bike.  Assistance level 2 gives you a noticeable speed increase on flat terrain where you will be at the max speed of the system (20mph) quite easily with just a modest amount of effort given by the rider and enough help on hills but still does not drain the battery to quickly...on flat terrain you should be able to do 20-25 miles on setting two.  Assistance level 3 is very will easily achieve the 20mph system max on flatter terrain with very little pedaling effort.  Assistance level 4 will be the setting you would use on your steepest hills...and with significant effort on your part you will be able to ride the steepest hills of Portland as long as they are not too long (less than 3 minutes of hard effort) where we would worry about the motor over-heating.  

WHAT ABOUT INSTALLING THE BIONX SYSTEM ON THE FRONT WHEEL?  Realize that if we installed the BionX system on the front wheel we would have no way to utilize the torque sensor (because the torque sensor needs to be connected to the wheel that drives the bike), and would require the use of a throttle.  This in my mind cancels out most if not all of the benefits of the BionX which is the torque sensor and the software that manages the system.  If we were to go with a front wheel drive power assist system, I would likely look at another system that does not have a torque sensor and elaborate software and instead put the $ towards a BIGGER battery and perhaps a BIGGER motor where the return on investment would be better. Reason for all of this is the BionX system is a premium system with a premium price...since we would not be needing these premium features, we would look to add value by giving you more hill climbing power and more run time from the battery.  

WHAT ABOUT INTERNAL HUB DRIVETRAINS AND USING A BIONX SYSTEM?  Unfortunately, compromises are a part of designing the perfect cargo bike.  I myself think the Shimano Alfine hubs are the best drive train going for cargo bikes and a lot of urban city bikes.  But when it comes to electric assist, the internal hubs get pushed to the side by motorized hubs and require the more traditional derailleur drive trains.  External drive trains, while not as ideal as internal hubs in some cases, still has advantages of being lighter, a little bit more efficient, a tad easier to work on (changing a flat tire for example) but importantly they are what the e-assist systems use.  If I were looking at a cargo bike with e-assist and I were forced to make a choice over a great electric pedal assist system that uses a derailleur -or- an internal hub with e-assist on the front wheel that uses a throttle...I would choose the former every time.  While a great internal hub is easy to operate and painless to is not that significantly better than an external derailleur drive train system.  When comparing the different types of e-assist systems, I definitely would look for a system that allows the rider to feel like they are still riding a bicycle, not a moped or a scooter where twisting throttles or holding down levers require the assistance to be maintained.  For me it is as much about the experience.  The BionX system compliments a bike and keeps the best part of riding a bicycle intact while giving the rider the kind of help they need in way that does not rob the rider of the joy of riding a bike.  For me, If it cannot be used with the Alfine hub, then so be it, not the end of the world-and I'm a huge Alfine internal hub fan.

WHAT ABOUT INSTALLING A BIONX SYSTEM ON A CARGO BIKE THAT IS NOT MADE TO OPERATE A FRONT DERAILEUR? Another something to consider on some Bullitt’s, the Winther Wallaroo and the Metrofiets is that these bikes were not designed to use front derailleur’s-only rear derailleurs or internal hubs.  But since we are talking a pedal assist system installation this is not a problem...Why?  Because most e-assist systems-and especially with the BionX PL-350-the system has so much power that you would never ever need to go into a small ring even if you had one. We have extensively tested the BionX PL-350 with a Bullitt with a triple crank and I can easily say I never have been in the smallest ring...and have only a couple of times spent any time in the middle ring-not because I had too, but because I thought I was going to have reality a single ring set up with a 42 tooth front ring going back to a 13-32 rear 9 speed freewheel gives you all of the low gears you need when it comes to pedaling up steep hills with a powerful motor and a battery.  So in the end, you end up with a single shifter on the handlebar...but instead of manipulating the internal gears, they move a derailleur up and down a rear gear cluster.  If you are concerned about quality and wear and tear on the drive train, we could spec top of the line Shimano mountain bike shifters and derailleur’s to give the bike added performance and durability.

WHO SHOULD LOOK AT A BIONX PEDAL ASSIST SYSTEM AND WHAT IS YOUR PERSONAL OPINION OF THE SYSTEM?   I am blown away at how nice that system is-very smooth, very easy to operate, perfectly quiet.  I like having the power to get across busy streets in a hurry and across town or up hills a lot quicker than un assisted cargo bike.  The more I ride it the more I like it.  It makes riding a heavily loaded cargo bike feel like a regular bike...and easier than a regular bike if you up the assistance levels on hills.  But most importantly, it still feels like the magic of riding a bike...that freedom and exercise induced endorphin "feel good" remains...not robbed by twisting throttles or noisy motors or any feeling that you are cheating I might add.  While the BionX systems are not best for every situation-probably not the best system for exceptionally hilly cities where climbs are very long and or very steep…where the BionX e-assist systems really shine are the moderately hilly areas like the east side of Portland.  Family cargo bikes or business cargo bike-either one-would benefit from a BionX pedal assist system.