By 1898 a rear wheel drive electric bicycle, which used a driving belt along the outside edge of the wheel was patented by Mathew J. Steffens. Also, the 1899 Template:US Patent by John Schnepf depicted a rear wheel friction “roller-wheel” style drive electric bicycle. Schnepf's invention was later re-examined and expanded in 1969 by G.A. Wood Jr. with his Template:US Patent. Wood’s device used 4 fractional horsepower motors; each rated less than ½ horsepower and connected through a series of gears.
If you are an experienced rider this is actually annoying as hell. Personally, I tend to leave whatever I'm riding in a high gear all the time, because my body is like a powerful machine, and I found the way it slowed my escape from the lights quite disconcerting. For beginners, it could be useful, but it's worth remembering that the whole point of e-bikes is that the motor helps you along anyway, so I do really question the usefulness of this.
I purchased version 2.0 of this device and the manufacturer has been listening to comments from users and making running changes such as the three speeds and the rear suspension. I am an XL size user (6'2", 230lbs) and recently returned from a 26 day cruise around Europe. I rode this little scooter on cobblestones, miles and miles through the Vatican, inside ancient cities and all over the streets of San Juan upon our return stateside. There was only one time it was less than ideal and that was going uphill, on slick tile that was wet from a drizzle. It still make it, just had to lean way forward to get weight on the front wheel.
Riding a pedal-assisted road bike may seem counterintuitive but during longer training sessions, the minimal addition of power helps prevent overall muscle fatigue and injury. Similarly, those looking to enjoy longer scenic routes will appreciate the general boost an electric drive provides. With a top speed of 28 mph, the Road E+1 uses three power modes to give you ultimate control over your ride and assistance level. A four-point sensory system monitors the pedaling force allowing the motor to amplify your movements seamlessly.
Different gears and ranges of gears are appropriate for different people and styles of cycling. Multi-speed bicycles allow gear selection to suit the circumstances: a cyclist could use a high gear when cycling downhill, a medium gear when cycling on a flat road, and a low gear when cycling uphill. In a lower gear every turn of the pedals leads to fewer rotations of the rear wheel. This allows the energy required to move the same distance to be distributed over more pedal turns, reducing fatigue when riding uphill, with a heavy load, or against strong winds. A higher gear allows a cyclist to make fewer pedal turns to maintain a given speed, but with more effort per turn of the pedals.
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 have an effect on 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.
Tires vary enormously depending on their intended purpose. Road bicycles use tires 18 to 25 millimeters wide, most often completely smooth, or slick, and inflated to high pressure in order to roll fast on smooth surfaces. Off-road tires are usually between 38 and 64 mm (1.5 and 2.5 in) wide, and have treads for gripping in muddy conditions or metal studs for ice.
Since 2000, Canada's Motor Vehicle Safety Regulations (MVSR) have defined Power Assisted bicycles (PABs) as a separate category, and which require no license to operate. PABs are currently defined as a two- or three-wheeled bicycle equipped with handlebars and operable pedals, an attached electric motor of 500W or less, and a maximum speed capability of 32 km/h from the motor over level ground. Other requirements include a permanently affixed label from the manufacturer in a conspicuous location stating the vehicle is a power-assisted bicycle under the statutory requirements in force at the time of manufacture. All power-assisted bicycles must utilize an electric motor for assisted propulsion.
It appears Tennessee has not passed any legislation that applies to electric bicycles. Some people think the laws pertaining to a Motorized Bicycle should be used for an electric bicycle. However, a Motorized bicycle would be a gasoline powered device per state law as it is defined as "means a vehicle with two (2) or three (3) wheels, an automatic transmission, and a motor with a cylinder capacity not exceeding fifty cubic centimeters (50cc) which produces no more than two (2) brake horsepower and is capable of propelling the vehicle at a maximum design speed of no more than thirty miles per hour (30 mph) on level ground." 
Ebike definition in Colorado follows the HR 727 National Law: Template:Convert e-power and Template:Convert max, 2 or 3 wheels, pedals that work. Legal low powered Ebikes are allowed on roads and bike lanes unless the city or county has passed laws to the contrary (Boulder city bans ebikes over 400W from bike lanes and all ebikes from bike paths) -none -(except Boulder city) have to date. Bicycles and Ebikes are disallowed on certain high speed highways and all Interstates unless signed as "Allowed" in certain rural Interstate stretches where the Interstate is the ONLY means of travel.  Unless the locality has specifically passed laws making ebikes illegal on sidewalks or trails, Ebikes are legal. However most business and shopping districts do not allow riding bikes or ebikes on sidewalks. Boulder and a few other cities specifically dis-allow ebikes on their trail systems through legal statute.