Buying an E-Bike: Key Considerations
Within the last several years alone, electric bike sales have skyrocketed and dozens of manufacturers have jumped on the bandwagon with new electric bike designs. With so many different options to choose from, how do you choose the right e-bike to suit your needs?
Before you start shopping around for a new e-bike, the first thing you should ask yourself is, “how am I going to use my electric bike?” How far are you going to travel? What type of terrain will you be traveling on? How much assistance do you need? Are you okay with pedaling – or do you want the bike to do all the work? Is this bike for daily commuting or casual riding? How fast do you need to go? Do you need an electric folding bike that fits in the trunk of your car?
After you’ve determined how you’ll be using your e-bike, you need to understand the different options available and the pros and cons of each setup. Here is an overview of some of thing you’ll need to take into consideration when shopping for the best electric bike:
Pedal-Assist vs Throttle Control
E-bikes have two main methods of operation: pedal-assist and/or throttle-control. As the name implies, pedal-assist “assists” your pedaling and requires some input. With this method, a torque sensor picks up movement or stress to determine the power requirements of the rider. Everything is automated so there’s nothing to think about, just jump on and start riding. Some bikes have multiple settings, while others have just one setting with the addition of a throttle control. Depending on the setting, pedal-assistance can help a little – or a lot. At lower settings, pedal-assist is barely noticeable but helps extend your range. At higher settings, the power is quite obvious and feels like a strong wind at your back with the motor doing most of the work while you pedal along.
A throttle-control, on the other hand, doesn’t require pedaling at all. Just like a motorcycle, twist and hold the throttle back to control power and speed. You can assist by pedaling along, but it’s not required.
Some e-bikes operate in pedal-assist only, others have a throttle, and some have both. Generally, pedal-assist only bikes will provide multiple power settings to choose from to help customize your ride, while bikes with both throttle and pedal-assist will have limited pedal-assist options. With these bikes, the throttle provides full control (when needed) while pedal assist is just a secondary option, great on straightaways or open road.
Most electric bike models include brushless hub motors built directly into the front or rear wheel. Within the hub motor category, you’ll have a few additional choices available:
Geared Hub Motors – Most pre-built e-bikes use brushless geared hub motors. These motors have internal planetary gears that help transfer power from the motor to the wheel. Because of the internal gearing, these motors provide excellent torque but are limited in top speed. On the plus side, the improved torque means better take-off power and hill climbing ability. Plus, less wattage is required to get the motor turning and they’re typically small and lightweight. On pre-built e-bikes, these motors range from 200w-500w and go up to 20mph. But some aftermarket kits can be as powerful as 1000w, with increased top speeds and huge amounts of torque (ideal for extremely hilly terrain). Besides lower top speeds, these motors tend to be expensive and it’s possible the gears will eventually wear out and need to be replaced (this is highly unlikely, they las quite a long time).
Gearless (Direct-Drive) Hub Motors – Some conversion kits (and bikes) use gearless, direct-drive motors. On this type of motor, the axle that passes through the center of the motor is actually the axle of the motor itself, with the copper windings fixed to the axle. The magnets are mounted to the outer shell of the hub motor. When electricity is applied to the stator a magnetic field is induced that causes the magnets to move. This in turn makes the whole shell of the motor turn and propels the e-bike forward. Even though corrosion will eventually have an impact, this type of motor should last for years since there’s no gearing and no contact between moving parts. They’re also capable of higher top speeds. But since there’s no gears, they have less torque and it requires more power to get the motor up to speed. Most direct-drive hub motors are 350w-500w and reach speeds of 18-25 mph. But more powerful motors can reach speeds of 35+ mph.
A few lower-cost setups use externally mounted, chain-driven motors. Although these setups are low-cost and provide a good amount of torque, they’re not nearly as quiet, efficient or ‘stealthy’ as the hub motors being used on most models. They are negligible though.
Battery Options and Charging
Battery technology continues to improve every day. Today, most commonly used type of battery on electric bikes is the Lithium-ion battery. Lithium Ion (Li-Ion) batteries are the highest quality batteries available in today’s market. Although they cost the most money upfront, they have the longest life and the lowest weight., which makes them a perfect solution for electric bikes.
E-bikes are typically offered in 24V, 36V and 48V configurations. Higher voltage generally means higher top speed – but that may not always be the case. Since the efficiency of a motor and drive system can affect power and speed, a 24V setup could have the same top speed as a 36V setup. Generally, you can expect 15-18 mph on a 24v setup, 16-20 mph on a 36V setup and 24-28 mph on a 48V setup. Although it far exceeds Federal laws, some conversion kits can even be run at 72V for speeds of 35+ mph! However, this puts significant stress on bicycle components. Consider that even the fastest athletes only travel 17-18 mph on a conventional bicycle, so 20 mph feels very fast to most riders. Anything over this speed can be unsafe and exceeds law regulations.
Besides voltage, batteries are rated by amp hours (AH). Although voltage seems to get the most attention, the amp hour rating of the battery is just as important. It is the measure of a battery’s capacity and provides a good indication of the range you can expect from an electric bike. Although lots of factors come into play in determining range (ie: rider weight, terrain, input, efficiency, etc.), a good rule of thumb is range is equal to AH. So under normal conditions, an average rider can expect 10 miles out of a 10AH battery (with no pedaling). With rider input, this number can be dramatically increased, so most 10AH batteries are rated “up to 20 miles” by the manufacturer which assumes pedaling. On pedal-assist bikes (which require pedaling), the range ratings are much higher because the rider is constantly assisting the motor and reducing the current draw.
Charging: Battery charge times will vary between manufacturers, models and battery types. Typically, the initial charge will take 6-12 hours. For routine charging, higher quality batteries (such as Li-Ion) will take less time – anywhere from 2-6 hours.
Electric bikes vary widely in price, anywhere from $499 to $2000+, so you’ll have to determine how important certain features are to the overall cost. The battery used to power an electric bike motor is a key factor in how expensive a particular bike is. In general, the more miles a battery can provide, the more expensive it will be, so it’s important to consider the type of riding you plan on doing. If you know you’ll be using predominantly motor-generated power, then paying a bit more for a battery with a longer range is probably a good idea. Alongside with a good quality battery, motor is the most expensive part of an electric bike. Most standard electric bike motors come with a power rating of 250W, and the industry standard in the US is 500W. Maximum power of the motor you can legally use in the US is 750W.
The non-electric components used on an electric bike are almost the same with those used on conventional bicycles. The quality of the components used will affect the maintenance costs of your electric bike down the road, and more quality components mean higher upfront cost. Lastly, there is the frame. Since the frame is basically the skeleton of your electric bike, it’s wise to select a good material that will be the optimum combination of weight and durability.
If you want a decent e-bike, that will last you a long time and won’t require much maintenance, you will need to spend over $2000. Anything less requires careful planning and probably some compromises.
Max Load Capacity
The vast majority of electric bikes on the market are rated for a max load of 220-250 lbs. This is plenty for the average rider, but if you are a heavier rider (over 250 lbs), then you will want to make sure to find an e-bike with a higher weight capacity. Most manufacturers list their max load right in the product specs. If you can’t find it, give them a call and they will be able to tell you.