Bicycles were introduced in the late 19th century in Europe, and by the early 21st century, more than 1 billion were in existence at a given time. These numbers far exceed the number of cars, both in total and ranked by the number of individual models produced. They are the principal means of transportation in many regions. They also provide a popular form of recreation, and have been adapted for use as children's toys, general fitness, military and police applications, courier services, bicycle racing and bicycle stunts.
The great majority of modern bicycles have a frame with upright seating that looks much like the first chain-driven bike. These upright bicycles almost always feature the diamond frame, a truss consisting of two triangles: the front triangle and the rear triangle. The front triangle consists of the head tube, top tube, down tube, and seat tube. The head tube contains the headset, the set of bearings that allows the fork to turn smoothly for steering and balance. The top tube connects the head tube to the seat tube at the top, and the down tube connects the head tube to the bottom bracket. The rear triangle consists of the seat tube and paired chain stays and seat stays. The chain stays run parallel to the chain, connecting the bottom bracket to the rear dropout, where the axle for the rear wheel is held. The seat stays connect the top of the seat tube (at or near the same point as the top tube) to the rear fork ends.
The batteries are the most important parts of the bike, because (if you don't do any pedaling) they contain all the power that will drive you along. Typical electric bike batteries make about 350–500 W of power (that's about 35–50 volts and 10 amps), which is about a quarter as much as you need to drive an electric toaster. In theory, you could use any kind of battery on a bicycle. In practice, however, you want to use something that stores lots of power without being too heavy—or you'll be using half your power just moving the battery along! That tends to rule out heavy lead-acid batteries like the ones that start cars, though some electric bikes do use them. Lightweight lithium-ion batteries, similar to those used in laptop computers, mobile (cellular) phones, and MP3 players, are now the most popular choice, though they're more expensive than older rechargeable battery technologies such as nickel-cadmium ("nicad"). Typical batteries will give your bicycle a range of 10–40 miles between charges (depending on the terrain) and a top speed of 10–20 mph (which is about the maximum most countries allow for these vehicles by law). You can extend the range by pedaling or free-wheeling some of the time.
Bike is awesome, warranty support has so far delivered, but is a hassle to deal with (and hassle is acceptable and better than nightmare, or unresponsive/clueless/unhelpful/not-english-speaking). To be fair, this is the middle of Swag's busy season. Check tire inflation, check and tighten fasteners, seatpost and handlebars and stem out of the box, RTFM, charge the battery and you're out the door riding quickly.
^ Consumer Product Safety Act, Pub. L. 107–319, December 4, 2002; codified at 15 U.S.C. 2085(b): The CPSC regulations do not differentiate between commercially manufactured low speed electric bicycles and those converted from ordinary bicycles by their owners using an aftermarket electric motor and battery kit, nor do they regulate the construction of electric-power bicycles using owner-built or sourced components.
In the United States electric bikes have seen slow but steady growth since the late 90’s and as a result, in 2001 congress was lobbied and passed the first and only bill to define ebikes in federal law. This law, 107-319, exempts electrified bicycles with operating pedals using motors under 750 watts limited to 20 mph from the legal definition of a motor vehicle.2.
While I would have loved to see some higher end components such as disc brakes or built-in lights, the bike still works well for what you get and is a pretty good value for the price. One missing component that I feel would make a big difference is a kickstand. I’ve never seen an e-bike that didn’t come with one, outside of ultra premium multi-thousand dollar road and downhill e-bikes that try to save every gram of weight. But for a commuter, a kickstand is pretty important. You can always add a cheap $7 kickstand from Amazon, but I would have preferred they save us the step and include their own cheap kickstand.
Historically, materials used in bicycles have followed a similar pattern as in aircraft, the goal being high strength and low weight. Since the late 1930s alloy steels have been used for frame and fork tubes in higher quality machines. By the 1980s aluminum welding techniques had improved to the point that aluminum tube could safely be used in place of steel. Since then aluminum alloy frames and other components have become popular due to their light weight, and most mid-range bikes are now principally aluminum alloy of some kind.[where?] More expensive bikes use carbon fibre due to its significantly lighter weight and profiling ability, allowing designers to make a bike both stiff and compliant by manipulating the lay-up. Virtually all professional racing bicycles now use carbon fibre frames, as they have the best strength to weight ratio. A typical modern carbon fiber frame can weighs less than 1 kilogram (2.2 lb).
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.
In China, e-bikes currently come under the same classification as bicycles and hence don't require a driver's license to operate. Previously it was required that users registered their bike in order to be recovered if stolen, although this has recently been abolished. Due to a recent rise in electric-bicycle-related accidents, caused mostly by inexperienced riders who ride on the wrong side of the road, run red lights, don't use headlights at night etc., the Chinese government plans to change the legal status of illegal bicycles so that vehicles with an unladen weight of 20 kg (44 lb) or more and a top speed of 30 km/h (19 mph) or more will require a motorcycle license to operate, while vehicles lighter than 20 kg (44 lb) and slower than 30 km/h can be ridden unlicensed. In the southern Chinese cities of Guangzhou, Dongguan and Shenzhen, e-bikes, like all motorcycles, are banned from certain downtown districts. There are also bans in place in small areas of Shanghai, Hangzhou and Beijing. Bans of "Scooter-Style Electric Bikes" (SSEB) were however cancelled and in Shenzhen e-bikes may be seen on the streets nowadays (2010–11).
The two most common types of hub motors used in electric bicycles are brushed and brushless. Many configurations are available, varying in cost and complexity; direct-drive and geared motor units are both used. An electric power-assist system may be added to almost any pedal cycle using chain drive, belt drive, hub motors or friction drive. BLDC hub motors are a common modern design. The motor is built into the wheel hub itself, and the stator fixed solidly to the axle, and the magnets attached to and rotating with the wheel. The bicycle wheel hub is the motor. The power levels of motors used are influenced by available legal categories and are often, but not always limited to under 750 watts.