Monday, January 30, 2017

Electric Bike Buying (and Building) Advice

Is this you?

If you're thinking about (or dreaming about) purchasing an electric bike, the choices can be a bit overwhelming. So, before you go buy one, let's look at some components you're going to want to know a little more about. We'll start with the motivation.

Hub Motors

The biggest question on hub motors is whether to go GEARED or DIRECT DRIVE. (The second biggest question is front-motored or rear-motored,)

Geared  Hub Motors

The Vanmoof Electrified S has a tiny geared hub motor in the front wheel

The biggest advantage of a geared hub motor is that they can freewheel when there is no power being applied. In other words, you can (mostly) pedal it just like a regular bike. (If you run out of battery power on a geared hub motor, you can pedal it home. If you run out of battery power on a direct drive motor, two city blocks will wear you out!) Geared motors are also smaller, lighter, stealthier, and a tiny bit noisier than a direct drive. One thing that is not possible with a geared motor is regen (power regeneration - where the bike actually recharges the battery {a little bit} when slowing down or coasting downhill).

Direct-Drive Motors

The Radwagon (of my dreams) uses a direct-drive rear hub motor

For bicycles, I am not a big fan of direct drive motors, but that is because they are heavier, less stealthy (because of their size), and because I can't coast with one. But those same drawbacks become virtues when you want your bike to behave more like a motorcycle. If you want to go really fast, carry heavier loads, or use regen, you want a direct-drive motor. They are a great choice for people who don't want to pedal and for people who want their bikes to be workhorses.

Mid-Drive Motors

Bafang BBS Mid-Drive Kit (photo from Lunacycle)

with a 350-watt Bafang Max mid-drive motor

I have no real-world experience with mid-drives, so I won't weigh in much, but I'd sure like to try out a BaFang BBS mid-drive set-up. Mid-drives are awesome hill climbers but they are much harder on chains, gears, and derailleurs. Their three big advantages are that they allow you to better utilize your bike's gear range, flat tires are much easier to change, and the motor weight is located in the center of the bike.

Lots of high-end (expensive) e-bikes are running mid-drives these days - the Bosch motor is the most well-known of the pricier mid-drives.

Battery Size

(For reference: a very common e-bike battery is a 36 volt, 8.8 Amp-hour)

Battery Voltage  (V)

Higher voltage means higher power and more speed.
If you are tiny and not in a hurry - 24 volts is great
If you are 200 pound or less, 36 volts should be enough
I f you are over 200 pounds or plan to carry extra weight - go with 48 volts
If you want to rock n roll, go for 72 volts! (Definitely not for beginners)

(Compare their Amp-hours per distance and power consumption.)

Battery Amp-Hour (Ah)

Amp-hours is a measure of how long a battery can deliver power - so the higher the amp-hour number, the farther your e-bike will travel. Juiced (in the diagram above) offers some very large amp-hour batteries, which is why they can offer ranges over 100 miles, but very few of us need that kind of range in our daily rides. Figure out what range you do need before you go shopping. While you can always upgrade, batteries are the most expensive component on most e-bikes.

Dash/Display Readouts

LCD Readouts - so much better!

Having a read-out that tells you what is going on is great!!! Most LCD dashboards will tell you how fast you're going, how far you've gone, (roughly) how much further you can go, how much power you are using, how much power you have left, and what assist level you are using. LED indicators, on the other hand, will give you a vague knowledge of how much power you are using and of how much you have left. They will also let you know what assist level you are using (if that applies to your bike.)

LCD displays keep you very well informed. LED indicators are pretty vague and less helpful, but they are much cheaper.


Just a general note, if you plan to pedal a lot, you will probably like a skinny seat more; if you plan to pedal very little, get something big and cushy.

Pedal Assist, Throttle, or Both?

This one also depends a great deal on how much you want to pedal and how much you want to sit back and cruise. I like pedal assist because I like to pedal and I like that pedal-assisted models give you the option of more efficiency which increases a bike's range. On the other hand, it's sometimes nice to have a throttle to help you take off more quickly when you are dealing with traffic. (It's really nice to have both.)

Multigear or Single Speed?

Single speed is not bad if you live in a flat place or are not planning to pedal. The bigger your hills, the more you need multiple gears, but electric bikes in general don't need as many gears. Anything over nine tends to be overkill.

where you can watch your dog run away for three days
before he's out of sight. (Man, I miss that dog!)

Weight Distribution

Whatever keeps the weight low and spread out (or centralized) makes a better e-bike. Placing all of the weight (battery and motor) on the back wheel is a bad idea that leads to bent rims, loose and broken spokes, and awkward handling. Having the weight up high leads to the bike falling over a lot while parked. If you plan to add a rack for cargo, keep that extra weight in mind when shopping or planning a build. (By the way, it's much more comfortable to let the bike carry the weight rather than your body. Panniers beat backpacks!)

A Final Piece of Advice

Before you decide completely what you want, sit down and make a list of what you need. How far will you travel? How fast will you need to travel? Are weight and size a consideration? Do you need an easily removable battery or wheels? What terrain will you travel? What's your budget? Most important, which bike will make you look truly cool?

I hope this makes your search easier and that your wheels tread lightly while your face smiles all the way to your destination.

May you be the change and encourage others to do the same.