We have shown so many e-bikes on TreeHugger lately. E-bikes can be wonderful things, great for older riders, people with really long commutes or who live in cities with lots of hills. But there are now so many different kinds, and there are a few basic questions that just never seem to get asked or answered. Mike previously asked e-bike expert Court Rye to tell us everything you need to know to get started on an electric bike, but I think there are larger questions to be asked.
I am not an expert on this, and want to go back even further, to first principles. I also look forward to comments from readers with more experience and knowledge.
How fast should they be able to go?
So many of the e-bikes we have shown have 500 watt motors and go 20MPH when the average commuting cyclist goes half that. Where I live, these monsters are considered e-bikes and I have been scared to death not a few times by jerks on e-scooters going 20 MPH in the bike lane; I know they are a different, particularly annoying creature than a bike, but 20MPH is too fast.
In the EU, the de facto standard for an electric bike that can be treated as a bike is:
"Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h (16 mph) or if the cyclist stops pedaling."
That’s a tiny motor compared to what we are seeing on TreeHugger, a slower speed limit and note that they are pedelecs, where the motor is giving an assist and stops when the cyclist stops, probably with no throttle option. More bike, less motorcycle.
On Copenhagenize, Mikael notes that e-bikes are involved in a disproportionate number of crashes and injuries. “11% of cyclist fatalities were caused by the fact that the cyclist was on an e-bike. Going too fast, losing control, motorists surprised by a speed faster than the average cyclist.” Perhaps we should be learning from this and slow them down a bit.
Front hub, rear hub or central drive?
A lot of the lower end e-bikes, like this Coolpeds iBike, are front hub drive. This makes sense; they are the easiest and cheapest to build. But they scare me; years ago I had a moped, a French Solex with front wheel drive. They were known death machines, with too much weight on the front wheel and a tendency to spin out on corners. Obviously a little hub motor in front is not the same thing, but they can still be problematic on corners and on wet pavement, especially if they are more powerful.
There is also the issue of the forces being applied to the front forks. According to Eric Hicks of Electricbike.com,
Hub motors put a lot of twisting torque on a bicycles drop outs, more than any bike was designed for. This is a special concern when running a hub motor on the front, because if your fork snaps, it can have potentially fatal consequences (think face plant onto the concrete). There have been electric bike riders who have died this way so use extreme caution. The more powerful the motor the greater the danger.
This is particularly a problem with aluminum bike forks. Also, electric motors can occasionally seize up; if that happens at high speed on a front hub, you can go flying.
Rear Hub installations are more complicated, because of the chain and the gears (or belt as seen on this Faraday) But they have better traction because of the greater weight on the wheel. It is considered safer, and delivers a smoother ride. But it is harder to fix a flat, and if the battery is also at the rear there may be a tendency to do wheelies.
Then there is the mid drive like this Bosch unit, designed into the frame of the bike, that is becoming more popular. I liked it because the bike is engineered around it, the center of gravity is really low, it was a pleasure to ride. But Laurence Clarkberg of Boxybikes tells TreeHugger that it “has issues of its own such as more points of failure, requires more user skill, and puts lots of wear on the drive train.”
The consensus seems to be that front hub motors are the easiest and most economical, but keep them small. Read more on this at ebikeschool.com.
Fixed or removable batteries?
I love the look of the Faraday bike up top, or the Maxwell below, where the batteries are built right into the tubes of the bike. It is elegant and it looks like a bike. But it is not necessarily practical; In Seattle, Brad rides this bike to the Bullitt Center every day, and there are no outlets in the bike storage room to charge an e-bike. By having a detachable battery he can carry it up to his desk and charge it there. I suspect that this is a pretty common occurrence.
Pedelec or Throttle?
In Europe, there isn’t much of a choice; almost every bike is a pedelec, where the bike detects either the torque or the cadence of the cyclist pedalling. Because it is all about assisting, not replacing, the pedalling. But North Americans don’t seem to get it, and since it’s not legislated, buy the bikes with the throttles for that motorcycle feel. Having used both, I suspect that the pedelec is safer (one less thing to think about) and provides a bit more exercise, since you do have to pedal. The makers of the Boar electric fatbike, shown above while I was testing it told TreeHugger:
We chose to discontinue the throttle on the new model, though we did use one on our first model. Lloyd enjoyed the ride and thought it was intuitive. We agree and that was our goal. We gained some extra benefits from losing the throttle: a much cleaner cockpit that eliminates 3 wires - 2 for the brake lever power cutoff wires (required in most jurisdictions) and 1 for the throttle.
So after all that, what's the perfect urban electric bike?
In the end, I think we should be learning from Europe, where they have been doing this a lot longer. A big heavy thing with a big motor and a throttle is no longer really a bicycle. Many might complain about 250 watt maximum on the motor (even the wonderful Maxwell, which felt like a bike, had a 300 watt motor).
But a European style e-bike is really a bike with a boost, an electric assist. This is what is really needed for people to travel farther, to handle steeper hills, to ride later in life, to play nicely in the bike lanes. They should be bikes, or they should be out in the road with the motorcycles.