E-Brompton and BionX—Apples and Oranges

by BionX Electric Motor on March 28, 2012

In a relaxing bay setting, Turbo shows-off his E-Brompton

In a relaxing bay setting, Turbo shows-off his E-Brompton

By Turbo Bob

When the subject of this post came to light, the title came even quicker. Just like these two fruits are similar, they are so very different. And so it is with the E-Brompton and the BionX E-bike conversion kit. Both are good, good for you, and serve a very utilitarian purpose. Yet they are very, very different.

To start out, neither of the bikes I will discuss were designed with a electric motor-assist in mind. My BionX 48 volt (Special Edition Kit) was installed on a mid-priced Diamond Back mountain bike. It was spec’d fairly nicely, had an aluminum frame, and rode well. It offered 21 speeds, a decent front suspension fork, and 26 inch wheels. My Brompton H3L is a top-end folding bike that has 3-speeds, steel folding frame, and just a hint of rear suspension. It has 16 inch wheels and a more up-right seating position than the mountain bike.

Two different ebike kit mounting systems

The BionX motor mounts in the rear, as opposed to the E-Brompton that has the hub motor in the front. As far as riding is concerned, I like both front and rear mount hub motor layouts. They both drive the bike without any adverse handling changes. The front to rear balance of the BionX is closer to 50/50. Part of that is due to the center mounting of the battery. There are other issues about which end the motor is mounted, but I won’t go into them here.

The E-Brompton does have a higher percentage of weight on the front (the motor and battery are up there), but during a ride, it is all but un-noticeable. Part of that is because the battery (mounted in the ’C’ bag) is secured to the head tube and not the handlebars. The only time when you notice the front being heavier is when you are moving the bike about or lifting it up onto a curb (or rise of some sort).

Total cost of ebike conversion

Another key point worth mentioning is the ratio of the price of the bikes to the price of the conversion kits. On the E-Brompton, the ratio is about one to one. On the BionX, it is (or can be) way different. Do consider I bought the 3 year-old Diamond Back used. The ratio here is about twenty-five to one. This speaks in many directions and I will leave it up to you to decide what those are. The total value of each complete E-bike is close to the same.

What you really want to know about is performance, range, and controllability. I think we can consider the reliability to be the same. Both bikes have a very professional look and neatness in the installation. The total weight is about the same (both under fifty pounds). And both bikes have a stealthy, non-E-bike appearance. The battery on the BionX does give away some of the fact that it is an E-bike. Plus the hub motors are visible, but not over-obvious.

Turbo takes on some rays on his BionX equiped mountain bike

Turbo takes on some rays on his BionX equiped mountain bike

The E-Brompton is a throttle-control only bike. It does offer three-levels of assist, but when on the high setting, the throttle has the complete range of control. The thumb throttle is at your left hand grip, and you must manipulate it continuously when you want the motor-assist. It is a simple set-up, uses a simpler and less expensive ECU (electronic control unit), and many people prefer this type of control over the motor’s power.

The BionX bike motor has a dual-control, intelligent pedelec system. It incorporates an integral load sensor that knows how hard you are pushing on the pedals and adds the motor’s assist automatically. With four levels of assist available and an energy regeneration ability, it is the king in using the available power wisely. A thumb throttle is included, along with a display panel that shows many important things. Those are– power used or regenerated, level of assist, battery power remaining, bike speed, distance traveled, and other cool things.

Riding an ebike, Brompton or BionX…

Riding with either control system is fine. The BionX motor is completely silent and noticeably smoother. The E-Brompton is a close second. Using the assist from a dead stop on the E-Brompton will bring on a little roughness and should be avoided. The BionX’s complex electronics won’t allow the motor to kick-in until you have reached a couple of mph. They have a fairy equal amount of power and acceleration, but the higher wattage of the BionX (350 watts vs. the E-Brompton’s 290 watts), does give a bigger boost at the higher speeds.

Range is a tough number to nail down. It depends on many factors. If you never pedal and count on the motor for all your movement, the battery will deplete pretty fast. If you only pedal, the battery will never run down. Of course, you won’t be at either of these extremes. I have taken both these of these bikes on 30 mile plus rides without running out of power. I’m sure I could have gone farther if I had wanted to. Keep in mind that my E-Brompton does have the 10 Ah battery option.

So who is the winner here? Apples or Oranges, which do you like best? I can’t choose either. I love the quality and smooth feel of the BionX. I love the ability to fold-up the E-Brompton and the convenience that it brings. Both bikes take me where I’m going and push me up the hills with a smile. Both bikes ride great and give a feeling that nothing can stop me from having fun. They are exactly the same and yet completely different. Go figure. Try them both and make up your own mind.

Got to go, time for a snack, Turbo Bob.

“After a time, habituated to spending so many hours a day on my bike, I became less and less interested in my friends. My wheel had now become my one and only friend. I could rely on it, which is more than I could say about my buddies. It’s too bad no one ever photographed me with my friend. I would give anything now to know what we looked like.”—Henry Miller, My Bike and Other Friends.

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