Riding an Electric Bike

Key Points

  • An electric bike is best imagined as a joint effort: it works best when pedaling and using the motor together
  • It should be note that the motor is inefficient at low speeds and so can struggle on steep hills; mid drive systems such as that provided by Empowering E-Bikes will generally have superior hill climbing ability

Riding an Electric Bike

Riding an electric bike is extremely similar to riding a standard bike, and will rapidly become instinctive. It is a joint effort; the pedals will drive the bike as normal, but with the motor (activated by either a sensor that activates when the pedals are turned, and/or a throttle) adding power as required. It is possible to ride pedaling hard and using not much power from the motor (which will increase range), or it is possible to ride pedaling gently and with lots of assistance from the motor, according to personal preference. 

From personal experience however, I would definitely say that you should always be pedaling to some extent, even if this is just turning the pedals and letting the motor do all the work. One reason for this is safety in traffic; a car driving seeing a bike rider who is not pedaling will assume they must be slowing down and will behave according. However, more generally, it somehow just feels wrong not to be pedaling on a bike, even if the motor is perfectly capable of powering the bike without you helping! I think this is simply because pedaling is what you do on a bike. For further confirmation of this phenomenon, refer to the flying scene in ET The Extra-Terrestrial and note that Elliot clearly pedals all the way (as do all the riders in the later chase scene) even after losing contact with the ground and clearly relying entirely on E(-T) power; pedaling is what you do on a bike. (Any implied association between this scene and an E E powered test ride is of course, entirely gratuitous :) ).

There is one aspect that it is useful to understand in order to ride efficiently and enjoyably. This is that the performance (efficiency and power output) of an electric bike motor depends on how fast the motor is spinning (motor rpm).  This is important to understand, since an electric bike motor does not contain different gears as the engine does on a car. A good way to understand the situation of the motor is by analogy to a rider on a single speed bike, with just one (fairly high) gear 

  • As the rider starts off, s/he will have to push very hard on the pedals to get going, but the effective power and acceleration is not very much
  • As speed picks up, the rider gets into a comfortable rhythm; the power to keep up a good speed is not excessive, and the rider can easily accelerate if needed
  • As the speed becomes too fast, then the rider's legs can't turn fast enough to keep up, and so the rider can no longer provide any power unless the bike slows down again 

The above description is an almost exact description of how the motor behaves. 

  • At low speeds the performance of a motor is low
  • At intermediate speeds the motor has good performance, reaching typically 80% or higher efficiency and maximum effective power output
  • At speeds too fast for the motor performance drops down again

Therefore, to get the most out of an electric bike, the rider should try to keep the motor speed at its comfortable level as far as possible. This means 

  • Firstly, the rider should pedal as much as possible when starting off, to help get the motor up to speed (although on the flat the motor will probably have enough power to do this anyway).
  • Secondly, and much more importantly, the rider should keep up enough speed on hills to keep the motor turning at its optimum rate. Slightly counter-intuitively, its far more efficient (as well as more fun!) to go fast than to go slow up a hill
  • If a hill is too steep that even with maximum pedaling and motor power available the bike starts to stall (i.e. slows down, so gets less efficient, so loses more speed and so becomes even less efficient and so on...you will be able to feel this) then its best to get off and push (maybe using the motor to propel the unladen bike). Forcing the motor to work hard at low speeds (which can damage the motor, as with any engine driven outside its comfort zone). 

Furthermore, when selecting an electric bike, be aware that different bikes will have different hill climbing abilities, even if they are rated with the same power output. Mid drive motors drive the bike via the bikes gears and so the motor can spin at its optimum speed while the bike travels more slowly up a very steep hill in a low gear; hub drive motors have to turn with the speed of the wheels and so stall out more easily on hills.