A guest article by James Thomas of BicycleDesign.
If you visit cycling websites on a regular basis, you have probably noticed at least a few references to electric bikes lately. New e-bike designs have been popping up in greater numbers at the various bike tradeshows, and electric bikes from companies like Lexus and Volkswagen have been getting a lot of attention from the mainstream press. As the category continues to grow here in the US, I expect that we will to hear a lot more about e-bikes. Holland, a country that is already known for high rates of transportational cycling, has experienced an e-bike boom in recent years. In 2009, Dutch bike shops made more money from e-bike sales than city bike sales and today, e-bikes account for a quarter of all bicycle sales in Holland by some estimates.
For the most part, the e-bikes that are currently on the market can be divided into three basic categories; throttle assist, pedal assist (pedelec), and throttle only. I’ll go ahead and make it four categories to include the various add-on systems that allow for the conversion of any bike into an electric one. In this post, I will briefly discuss the different categories of e-bikes that you have probably been hearing a lot about lately.
Throttle powered assist e-bikes
The simplest, most straightforward ones on the market. These bikes can come as singlespeeds or with multiple gears. Basically, the rider pedals and shifts as he or she would on a regular bike, but there is a hand operated throttle to provide power from the electric motor when necessary. These bikes are versatile because they can be propelled by the rider only, the motor only, or any combination of the two. The majority of throttle-operated e-bikes have a flat battery pack that is located in a specially designed rear rack and a motor in the rear hub. When you reach your destination, the battery pack can be easily removed from the bike for charging. Pedego is a good example of a company that makes throttle assist e-bikes in a range of styles.
Pedelec, or pedal electrics
Also referred to as “pedal assist” bikes. With a pedal assist bike, the motor starts contributing to the bike’s motion as soon as the rider starts pedaling. As the rider pedals faster, the power from the motor also increases (until it reaches a preset max speed) effectively amplifying the human power. On a pedelec, the rider has to pedal in order to propel the bike, but the motor provides assistance to allow him or her to cover more ground at a faster pace. The Sanyo Eneloop is one electric assist bike that has been getting a lot of attention lately. That bike features -loop charging’ which means that the battery recharges as the bike is ridden. I had the opportunity to ride an early version of the Eneloop at Interbike last year, and you can read my impressions of the bike here. It is worth mentioning that there is overlap between the throttle operated and pedal assist categories. Some of the iZip bikes from Currie Technologies for example, allow the user to easily switch between throttle and pedal assist modes.
The third category that I mentioned is “throttle only” for lack of a better term. These are the “e-bikes” on the market that are not really bicycles at all (the YikeBike and the Volkswagen bike that I mentioned earlier are examples that have received a lot of press attention). These e-bikes don’t even have pedals, so they would be better classified as electric scooters. So, you might wonder” why are they referred to as e-bikes? A lot of it has to do with marketing and legal definitions of the term. In many countries, e-bikes can be operated without a license or helmet (unlike an electric scooter or moped), so manufacturers would rather have their vehicles classified that way. As the e-bike category matures and groups representing manufacturers and users debate regulations, hopefully the definitions will become clearer. For now though, don’t be surprised to see mentions of e-bikes that are really just electric scooters in disguise.
E-Bike Conversion Kits
Retrofit e-bike conversion kits come in a variety of types. Systems like the ones available from BionX, with motors that range from 250 to 500 watts, can turn almost any bicycle into a powerful, long-range e-bike. Other kits, like those from Cytronex, and Freedom E-bikes use smaller and lighter batteries to provide just a boost of electric assistance when needed. As battery technology improves, I expect that we will see a greater variety of e-bike conversion kits that are easily to install and remove when not in use.
This post has just scratched the surface regarding the different types of e-bikes, but there is a lot of good information available on the web. The GOOD blog recently posted a helpful article titled “Choosing the Right Electric Bicycle” and forums like Endless Sphere and sites like ElectricCyclist.com are consistently good sources for electric bike information. Of course, as e-bikes continue to grow in popularity, you will also see them mentioned more often at my blog, Bicycle Design, and here at Commute by Bike. Even if you don’t feel like an e-bike is in your future, it is definitely an interesting category to keep an eye on.