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9590Re: Different e-assists

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  • toddfahrner
    Aug 31, 2009
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      --- In rootsradicals@yahoogroups.com, Bill Bonney <billbonney@...> wrote:

      > I have experimented with the BionX 350PL assist. It well made piece of
      > kit with good power. Battery life is good (in comparison to others at
      > the size/weight) It also has a neat system of sensing when you push on
      > the pedal, the more pressure you put on the pedal the faster you go.
      > You don't need to use a throttle to control assist. This means it
      > feels more like normal cycling

      I agree that this is a quality product, admirably simple in operation, but disagree that having pedal pressure serve both a throttle function and normal propulsion results in a normal cycling feel. My experience with these systems is that they train you to pedal differently (=more slowly, harder, anaerobic) to "trick" the system into assisting you more than it otherwise would. Either that, or you get more assistance at certain moments than you want. I consider it oversimple, substituting your sophisticated on-board computer (brain) for a simple algorithm. A manual throttle, while it adds a new control element to the normal biking experience, is at least yours to decide how to use, moment by moment.

      > The disadvantages are cost. It's also proprietary battery and
      > controller, so you cannot but different batteries from other
      > manufacturers, say if you wanted longer range, or shorter range and
      > lighter set-up.

      I would say the main potential disadvantage of this and most other "single speed" assist systems designed for normal (not cargo) bicycles is that they tend to be optimized, efficiency-wise, for cruising along on fairly level ground at maybe 18mph. With cargo and hills, or stiff headwinds, or lots of start-and-stop, they tend not to be able to spin up to their optimum working speed so end up creating a lot of heat relative to propulsion, limiting range for a given load of batteries.

      > But saying that.... the Stokemonkey, by clever cycles looks
      > interesting. I do think it could be more challenging to use though as
      > it requires the rider to be fixed into the pedals with cleats/tow
      > straps.

      This isn't true. There is no such requirement, and I think only a small minority of users use same. Thanks for alerting me to a perception problem with that line item in the warnings. I recommended foot retention back in the day in part because I was trying to imagine all kinds of gruesome fantasy liabilities of driven pedals and mitigate them. But here 5 years later still nobody's reported harm from not using retention of some sort.

      > It's a more avid cyclist focused product. It advantages is
      > that you can pair it with any battery tech, based on cost, weight etc...

      A number of other systems are battery-agnostic too. The main advantage is that by using all your bike's gears, the motor can deliver huge torque, necessary for heavy cargo in steep hills, and also good speed, without sacrificing efficiency.
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