Sunday, May 24, 2015

E-bike basics

To get around in the Metroplex with an e-bike you'll need the proper machine and tools.

First, the Endless Sphere e-bike forums are a very useful resource. I would read all you can here before doing anything. Anything I add here will be specific to my experiences traveling around in the DFW Metroplex.

In my experience, traveling around Dallas on an ebike sometimes involves some degree of urban mountain biking, so I highly recommend you get yourself a very solid mountain e-bike of some sort with at least 26" tires. Suspension is nice, but not necessary.

If you're not mechanically inclined, and don't have a friend who is, then you should look for a ready to go commercial ebike. Personally, I'm still pretty leery of commercial ebikes, mostly due to concerns about repairability, interchangeability of components, and long term robustness and reliability. There is only one local ebike vendor in Dallas I'm aware of, Small Planet Bikes. You can also order one online, some popular choices are from Predeco and Currie Technologies, but there are lots of other choices.

Personally, I prefer building my own, using parts and kits purchased from various US or Chinese vendors. Probably the most well known and well respected vendor in North America is Grin Technologies, but you can also check out Electric Rider. Ebay kits are easily found and much cheaper, but be very cautious because getting support or returning stuff to China can be quite a hassle. One well-known and respected Chinese supplier of batteries is Ping Battery.

I have three e-bikes at the moment, but my general purpose all-around favorite machine is a hardtail steel 26" Specialized HardRock mountain bike from the early 90's, with a 1000 watt front brushless direct drive hub motor. I've put around 4,500 miles on this e-bike over the years. This is my main commuter bicycle, and it has been through hell and back and survived.

Front, Rear and Mid Drive

Also see here for good coverage of the pros and cons of rear vs. front drive.

I've not used a mid drive machine yet, so I don't have much to say. One example is from Bafang. I prefer hub motors because of their simplicity, they are less noticeable, quieter, and they are easily repaired.

Front hub motors tend to be the easiest to install, and easier to remove to fix flats. Also, pedalling with the motor gives you two wheel drive, which can be very useful in muddy conditions, or going uphill.

One major downside to front hub motors is what I call wheel "slip". Especially in wet and muddy conditions, it can be quite easy to supply too much power to the front wheel, causes the wheel to skid. In dry conditions, a front wheel drive is pretty much just "point and go". In very muddy conditions (especially on muddy concrete trails after storms), front wheel drive can be almost useless, and in the worst case can cause you to fall if you try to simultaneously use the motor while turning. Front hub motors add a lot of weight to the front, but this tends to be balanced out by the weight in the back. Putting the batteries on a rear bicycle bag or trunk makes a lot of sense when using a front hub motor.

Another downside to front hub motors is the large amount of torque and stress they can apply to the front forks. General knowledge says they should be steel forks with no suspension.

Rear drive hub motors add a lot of weight to the back of the bike, so you'll want to mount the batteries as far front (and down) as practical to balance this weight out. Powerful e-bikes (2-3,000 watts) with rear motors have a tendency to wheelie unless the machine is well balanced. Rear drive is nice because you can use front suspension and aluminium frames with no worries.

In muddy conditions, I've found rear drive to be more stable overall. In fair weather conditions, I prefer front hub motors.

Be sure your e-bike hub motor has at least one torque arm, to prevent the hub motor from wrecking your forks or frame. Here's a good example.

Speed, power, voltage, and amperage

In general terms, a top speed of 20-25mph is great, and anything less than 15mph isn't fast enough unless you have lots of time to kill. Use the Motor Simulator at to get an idea how fast a particular configuration will go.

You want enough power to get you up the few hills in the metroplex, and to have decent enough acceleration (0-20mph in around 6-10 seconds). But you don't want too much power, because it'll cut down your range (unless you like carrying around 20+ pounds of batteries). Personally, I wouldn't go below 36v or below 700 watts. 48v 1000 watts should be more than enough for getting around on trails and streets. It should be possible to get by on less wattage if you optimize more for weight than I have, but anything less than 500 watts is probably too little. IMO anything more than 1000 watts should be reserved for mountain e-biking in the back woods.

Most bicycle frames and brakes are not designed to handle the speeds the more powerful hub motors (such as the Crystalyte 5304) are capable of. These motors can handle thousands of watts, and IMO are ridiculously heavy and powerful for something classified as a bicycle.

Unless you have some rare monster hills to deal with, controllers in the 20-25 amp range should be sufficient.

As far as batteries go, I prefer to be flexible. I'll cover batteries in another post. I've arranged my batteries so I can combine them in various ways to achieve higher voltages or amp-hour capacities. For a quick trip to the store, I can use my lightweight 48v 5Ah LiPo pack. For work, I use a 10Ah LiPo pack, and for far trips I can combine together both packs for 15Ah. For very far trips, I bring along multiple LiFePo4 and Lipo packs and switch batteries when needed.


The right tires are critical. If your ebike (or ebike kit) came preinstalled with some tires, be prepared to just toss them and replace them with real ones.

Knobby mountain bicycle tires will have great traction, but will have too high a rolling resistance for use on concrete and streets, and be pretty loud. The extra rolling resistance will noticeably reduce your range, and make it harder to peddle. The one advantage they do have is better traction in muddy conditions.

In very dry weather, slick tires are your best bet and the most efficient. An example is Continental's Town and Country tire. Note in wet and muddy conditions these tires are useless, even dangerous:

My current favorite are Continental's Double Fighter tires, which have low rolling resistance but good traction on turns:

Unfortunately, the Double Fighter tires completely suck in the mud, or on silt left over after floods.

Maxxis tires are also very good.


You want extra thick thorn resistant tubes, such as these from Slime. If you get Slime tubes, be sure to also buy a Schrader Core Removal Tool (and carry it with your tools on your bike), because the Slime stuff can occasionally get stuck in the valves and without a core removal tool you're screwed.


You'll need:

  • A good bright front bike light, preferably one with a separate rechargable battery. I use this one (1200 lumens). Don't even try to ride in the dark without a front light, it's suicidal.
  • An extra front light, probably AA or AAA powered, as a backup front light.
  • A back flasher.
  • Front and back fendors. It rains a lot in the Metroplex, and without fendors you'll just get soaked. I used these from Planet Bike.
  • A kickstand, which is a necessity on an ebike. You don't want your bike loaded with expensive (and sensitive) batteries falling down because you cheaped out and didn't get a kickstand.
  • Bicycle tools: You want the usual multitool, like this one, and a tire pump and a tire repair kit. You'll also want some additional tools for ebikes: a knife (for cutting wires), some electrical tape, some extra pieces of wire, an adjustable wrench, needle nose pliers, and some zip ties. For longer distance rides, a digital voltmeter is probably a good idea.


There is no such thing as bad weather, just bad clothing. Here's a list of stuff to get if you want to get around during bad weather:
  • Good gloves, for when (not if) you fall
  • A poncho, like this one
  • A pair of waterproof rain pants, such as this, or something from West Marine
  • Waterproof hiking shoes, like these from Merrell
  • A helmet cover
  • Shoe covers, like these
  • For winter e-biking, you'll need to wear long underwear, double socks, etc.
  • Even in non-winter weather you may need ear warmers, like these

Useful Tools

Here's a list of more specialized tools I've used to repair my ebikes at one time or another: 

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