Electric power assist bicycles have been around since before automobiles were mass produced, but they were very heavy - so you could actually go faster on a good conventional bike. Only in the last few years has eBikes technology advanced to where it is a sublime experience just like a bicycle, but faster. Many people have told us their eBike has reignited their passion for cycling. after years of slowly slogging up hills. To make the most of this new world, discover for yourself how to discern what is the right technology for you.
Twist & Go, and a basic geared front hub motor that could be added to almost any bike - even a monkey could manage this. This simple lightweight setup is the oldest, and it is still around in various forms.
It also suffers from some major limitations:
Under powered - usually 15mph and much slower on the hills
Tired hands - twisting or pushing the throttle gets to be a pain.
Scooter-like - not really exercise oriented if you want a workout
Range (how far the ebike will go on a full charge)- limited, usually less than 20 miles. Efficiency with a throttle was not very good.
Batteries - lead acid & NiCd had low energy density, bad memory, and were bulky and heavy, struggling to deliver enough oomph.
Anxiety battery sizes tended to be smaller without a power meter to tell when you are going to run out of juice.
Front Geared Hub & Throttle
Direct Drive & Cadence Sensing
With more powerful motors and pedal activation of assistance (when pedal are turning) - you could ape up a hill like never before. Usually featuring heavy "direct drive" motors (essentially a massive set of magnets) that delivered substantial acceleration. You could select modes to dial in your power and normal bikes could be retrofitted.
Jerky - a pedal rotation (aka cadence) sensor is like a throttle operated by your feet, but one that only knows all on or all off.
Heavy - to give you enough torque, these direct drive motors have to be as big as possible, consequently adding 13+ lbs, + the battery.
Efficiency - direct drive motors are about 30% less efficient than mid drives - the giddyup kick from a dead stop is what really eats into efficiency - consequently huge heavy batteries had to be used.
Gorilla - retrofitting tears up a bike that was not designed for this kind of tank-like weight and power. Very ropey looking as well.
Batteries - 1st Gen lithium-ion had better energy density, but for example, LiFePO (1rst Gen Lithium-ion) voltage would drop suddenly, making range calculation hard. Form factor was not standardized nor were safety certifications that were subsequently adopted.
Handling - these brutes had their outsized weight distributed all wrong for a normal bike riding feel. There was a gyroscopic effect (making turns feel weird) with the unsprung wheel weight. All that weight towards the back made the bike want to wheelie up on steep climbs. Having so much more weight meant compensating with heavier suspension or having a very harsh ride.
Currently, the best electric bikes have iPhone-like brains that take information from an array of sensors - speed, cadence (pedal rotations per min), torque (the force applied to the pedals) - along with the mode you selected - to give the controller total awareness of your riding so it can apply power in just the right amount, at the right time, for the experience to feel seamlessly natural Now it can also calculates your estimated range based the battery you have left, shown on the display.
Advantages of a mid drive system:
Power & Torque - due to the motor working with your drivetrain (instead of duplicating it), shifting to the right gear gives the kick needed to for hills, and also the power you will need for speed.
Batteries - State of the art lithium-ion cobalt cathode cells hold and deliver unprecedented energy.
Handling - locating the drive & battery as low and towards the middle of the bike as possible, it now steers and feels like a regular bike riding.
Efficiency is unprecedented and getting better all the time - the system doesn't waste motor power, like when you are going downhill.
The Modern "Force Multiplier" Mid-Drive eBike
So what is next? eBikes are the fastest growing electric vehicle trend of all times - and that shows no signs of slowing any time soon. Should you wait for the next leap to buy an eBIke? Here are some of the considerations:
Drive power - this has plateaued, and will probably stay that way because of regulations. eBikes are classed by power output (in watts) and max speed (250/20mph and 350/28mph). Over that, they are considered motorcycles (needing full DMV licensing) instead of bicycles, and limiting where eBike may go (like on bike paths).
Efficiency - innovations here are likely to be limited, but firmware updates & custom settings will continue to offer improvements.
Batteries - this is where the most advancement promises to be long term. Because most system changes have stabilized around proven "platforms", (like Bosch Performance or Brose S/T motors) when battery technology advances, new lighter & more powerful packs for existing platforms will become available. Promising chemistries that would be game changers, like lithium-sulfer are still 4 to 5 years away from a commercially viable cell.
Perhaps the most significant innovation in eBikes is really US, and our habits.
- Traffic is not going to move any faster. With a bike you just slip through the madness with wind in your hair and a smile on your face.
- The climate is not going to tolerate more pollution without cooking our earth. Maybe eBikes are part of the solution.
- Our waistlines are not going to shrink if we don't stay active. What are you waiting for?