Wow, I didn't realize there is so much negativity towards Bionx.
Ok, let's clear some misconception about the system. First of all, 2009 models come with throttle control in conjunction with the proportional power assist feature, so that you can ride home fully assisted. The only models that did not come with this throttle control was the original P-250 and the PL-250 up until early 2008 as an optional feature. Very late 2008 models, however became as standard feature as mine has one. Secondly, the system is proprietary because it is not simply a controller, computer, battery and hub arrangement, but rather a combination of conventional electric system with I suspect a built in power meter to measure the pedal power output of a cyclist (known as the strain gauge), much like an SRM crank or a Cyclops Power Tap rear hub. These are not new technologies, but they aren't cheap either. If you google either of them for a price, you will find that they aren't cheap -- try $1200 US for the Cyclops Power Tap economical setup, and that in itself doesn't come with a battery, hub motor and battery!! The expensive part is the strain gauge and the electronics that come with it.
Another misconception is the way the system works and I don't believe the description on http://www.ebike.ca is correct. It described it as an automatic electric assist system as opposed to the eZee which is manual assist. Here's a problem, how can you tell how much power you are putting out on the pedals so you can determine the correct manual assist while still keeping some resistance on the pedals? You really need to know your gear charts well. I tried it on the conventional system and it is difficult, but not impossible! You just can't and that's why, stuff like SRM and Power Tap are still being sold to train cyclists to become better cyclists. Even Lance Armstrong trains with a power meter!!
The idea of automatic assist or manual assist is simply this. In the Bionx auto assist, the power output of the cyclist is measured via the strain gauge in "watts" and then the computer system determines the level of assistance necessary and adds its own motor power. Say a relatively unfit cyclist can only put out 50watts of his or her own power and if the system is setup to provide a huge multiplier like 200% to 300%, the system can provide an additional motor power of up to 250watts (on the P250) or 350watts (on the PL-350) for a total of 300 watts or 400 watts. As you can see in this picture, the system provides a proportional assist to the output of the cyclist via pedal effort or pressure. A fitter cyclist can usually generate 100watts to 200watts easily of his or her own power. An elite cyclist can generate 300watts or perhaps higher in shorter intervals. The problem with this setup is with inexperienced cyclists who also happens to be pedal mashers! Pedal mashers are people who put the most pedal power stroke on the top down phase of the pedal stroke, usually past the 1 o'clock and close to 2 o'clock mark. As dogman described, this gives the pulsing and gliding effect of the Bionx system. But you DO NOT NEED a Bionx system to achieve this. A regular poorly trained cyclist does this anyhow with a conventional bike. Perhaps the tell tale sign of knee and ankle injuries are a result of poor bike posture and fitting rather blaming squarely on the system itself. May I suggest people with cycling injuries visit Sheldon Brown's website and understand what cycle fitting is.
The Bionx system works well with cyclists who can pedal smoothly in a circle and this helps maintain consistent power proportional assist, albeit with some occasional cogging effect from the hub itself. However, the system starts to shine if you are providing even more pedal effort in watts. If you are providing more watts for forward motion, the system eventually will put out less (it shows it on the graphical display) and this has the effect of conserving battery power. Whereas with a manual system, you will be using the motor power more because it's simply human nature to find the path of least resistance and motor power does that! The Bionx system, unlike other manual systems, still require the cyclists to do some pedaling. This form of resistance exercise is what keeps a cyclist fit. In fact, I was a pretty fit cyclist, but when I got the Bionx system and overused its throttle system because it's just so easy to get free speed, within 4 weeks of usage, I was struggling heavily once I got off the electric bike and onto my carbon race bike. You can become unfit as soon as you rely on a motor. And soon, you'll want an even more powerful motor to go faster. To me, it's nothing more than a glorified electric motorbike or moped and this is exactly mirrored in the sentiment of conventional cyclists. A cyclist with a bike and a 600w motor and a 48v or 72v battery is no longer a cyclist, but rather a passenger. This would explain why as motor power get stronger and more powerful is the tendency for people to go full suspension, cushy tires and suspension seatpost simply because, the pedaling forces aren't there to support your posture and or structure. Instead of using a musculature posture to ride the bike, you'll end up with a skeletal posture (sitting). You may get a lot of injuries like neck pain, shoulder pain, back pain near the Thoracolumbar Fascia, glutes pain, knee pain and ankle pain. A bicycle itself wasn't meant to be ridden sitting down with no pedaling forces and you simply can't pedal that hard anyhow with the gearing which was designed for a normal cyclist without motor assist.
Therefore, from a pure cycling stand point, the Bionx system is really the only automatic system that works well. It is not to say that a geared system or even a brushless DC system isn't good, it is just that as soon as you ADD a motor, hub and so forth, you are bolting on an additional 20 to 30lbs of weight, which is very noticeable as soon as you start hitting a hill. You will use the motor power more on a manual system because it is difficult to find the right rhythm from a combination of gears and throttle control, but if you can do that, then you are already a pretty good cyclist and you don't need a motor. The thing with reliance on a bike and motor is that, you want more motor power because like a car culture, we want more horsepower. Which means, you want more watts, more higher voltage, better controllers and these systems are not feather weight. It becomes more of a electric motor cycle and if this is what some people want, then it is what they will get. But please differentiate the difference between some one who wants total power assist and speed assist to someone who is looking to maintain a certain level of high fitness and wants to pedal but need the assist occasionally up a hill and getting to work relatively sweat free. In my part of town, the dedicated pedalers ride Bionx and my local dealer outsold Bionx all the time compared to the eZee geared hub. I rarely see the eZee system, but I saw one or two along some of our bike path. And I think I saw Zoot a few weeks ago in Vancouver, cycling along West 64th and stopped at Cartier st riding his Xtra cycle with a Cylte 5304? He looked at me, perhaps because I was riding my Dahon Mu SL with the Bionx.
Cheers,
David.
