Saddles also vary with rider preference, from the cushioned ones favored by short-distance riders to narrower saddles which allow more room for leg swings. Comfort depends on riding position. With comfort bikes and hybrids, cyclists sit high over the seat, their weight directed down onto the saddle, such that a wider and more cushioned saddle is preferable. For racing bikes where the rider is bent over, weight is more evenly distributed between the handlebars and saddle, the hips are flexed, and a narrower and harder saddle is more efficient. Differing saddle designs exist for male and female cyclists, accommodating the genders' differing anatomies and sit bone width measurements, although bikes typically are sold with saddles most appropriate for men. Suspension seat posts and seat springs provide comfort by absorbing shock but can add to the overall weight of the bicycle.

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.

The legal definition/description of an electric bicycle is most closely described in the code as a "motorized scooter" in that it is powered by an electric motor and/or human power [45]. It may be also be described as a "Motorized bicycle". However, that description does not include electric powered motor specifically. And it appears that the legal definition "Motorized Bicycle" and "Motorized Scooter" are in conflict. Motorized bicycle is a pedal bicycle which has a helper motor, or a non-pedal bicycle which has a motor, with a cylinder capacity not exceeding fifty cubic centimeters, an automatic transmission, and which is capable of a maximum speed of no more than thirty miles per hour. A motorized bicycle shall not be operated upon any way, as defined in section one within the commonwealth by any person under sixteen years of age, nor at a speed in excess of twenty-five miles per hour. A motorized bicycle shall not be operated on any way by any person not possessing a valid driver’s license or learner’s permit. Every person operating a motorized bicycle upon a way shall have the right to use all public ways in the commonwealth except limited access or express state highways where signs specifically prohibiting bicycles have been posted, and shall be subject to the traffic laws and regulations of the commonwealth and the regulations contained in this section, except that the motorized bicycle operator may keep to the right when passing a motor vehicle which is moving in the travel lane of the way, and the motorized bicycle operator shall signal by either hand his intention to stop or turn. Motorized bicycles may be operated on bicycle lanes adjacent to the various ways, but shall be excluded from off-street recreational bicycle paths. Every person operating a motorized bicycle or riding as a passenger on a motorized bicycle shall wear protective headgear conforming with such minimum standards of construction and performance as the registrar may prescribe, and no person operating a motorized bicycle shall permit any other person to ride a passenger on such motorized bicycle unless such passenger is wearing such protective headgear.

Controllers for brushed motors: Brushed motors are also used in e-bikes but are becoming less common due to their intrinsic lower efficiency. Controllers for brushed motors however are much simpler and cheaper due to the fact they don't require hall sensor feedback and are typically designed to be open-loop controllers. Some controllers can handle multiple voltages.
Nebraska defines a Moped as "a bicycle with fully operative pedals for propulsion by human power, an automatic transmission, and a motor with a cylinder capacity not exceeding fifty cubic centimeters which produces no more than two brake horsepower and is capable of propelling the bicycle at a maximum design speed of no more than thirty miles per hour on level ground."[69]
Are you looking for an easier way to get to your blind or tree stand? Or perhaps check all your trail cams in  a fraction of the time it takes today?  Is that sweet spot you know getting harder to reach? When you have to carry 50lbs of gear on your back for 5 or even 10 miles and if you’re lucky you have something to haul back out, using an electric bike built specifically for offroad and woodlands that is also capable of carrying your gear, wouldn’t that make the experience a whole lot more enjoyable? Electric hunting bikes...
One of the profound economic implications of bicycle use is that it liberates the user from oil consumption.(Ballantine, 1972) The bicycle is an inexpensive, fast, healthy and environmentally friendly mode of transport. Ivan Illich stated that bicycle use extended the usable physical environment for people, while alternatives such as cars and motorways degraded and confined people's environment and mobility.[105] Currently, two billion bicycles are in use around the world. Children, students, professionals, laborers, civil servants and seniors are pedaling around their communities. They all experience the freedom and the natural opportunity for exercise that the bicycle easily provides. Bicycle also has lowest carbon intensity of travel.[106]
None of this would matter if the VanMoof Electrified S2 (and its close relative the X2) wasn't fun to ride, but it is a blast. Like the Brompton, it pulls off the neat trick of powering you along but giving the illusion that you're doing the work, reacting quickly and cleverly to the speed of your pedalling and the difficulty of any incline you're on. 
Electric motorized bicycles can be power-on-demand, where the motor is activated by a handlebar mounted throttle, and/or a pedelec (from pedal electric), also known as electric assist, where the electric motor is regulated by pedaling. These have a sensor to detect the pedaling speed, the pedaling force, or both. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. Most controllers also provide for manual adjustment.
If you are a person who enjoys riding a bike casually at a typical bike path speed (10-15mph), and you like the idea of an ebike push up a hill, against the wind or to relieving a sore knee, then your market for a fully legally defined ebike is very broad and your practical use only has a few limitations. Most ebikes will meet your needs and expectation. I would estimate that 85% of the electric bikes on the market are 100% compliant meeting the federal definition. I encourage you to take the plunge and get a good quality ebike and ride more with assist. Do so with the confidence that electric bikes are here to stay. Coexisting with pedestrians and other cyclist will become a normal part of cycling life.
I found that by sticking it on 'Turbo' or 'Sport' mode (the upper 2 of the 4 electrical assistance levels) and leaving it in a middle gear, the Centros felt zippy when in full flight, but able to pull away from the lights with no problems. Less lazy riders than me might want to actually use the 10 gears, and will find that in the top gear, it's quite easy to push past the mandated 15.5mph electrical limit.
eBikes are a key part of solution to reduce carbon emissions globally. The Zero-emission part of the eBike discussion is based on re-charging the battery on a daily basis from a Sustainable Electrical Source such as solar, wind, hydro, geo thermal, etc.  The fact is today part of the eBike Battery charge is coming from Power Plants that are running …

I waited until I hit 100 miles on this beauty before writing this review. My riding buddies told me I couldn't get a quality ebike for under $3k. Absolutely the wrong advice. This Addmotor is amazing in every way. Well built, close attention to detail and a complete joy to ride. I would highly recommend this bike to anyone looking for a great ebike experience.

Regulations[37] appear to deal with Bicycles with helper motors. No person shall ride a bicycle with a helper motor unless that person holds a valid motor vehicle operator's license. No person shall operate a bicycle with a helper motor at a rate of speed exceeding thirty miles per hour; nor shall any bicycle with a helper motor be operated on any sidewalk, limited access highway or turnpike. Driver's licence is required except if a special permit is obtained by havnig a doctor fill out a certificate and shows they are able to drive the bike with and without the motor assisting.
So first off, it isn’t fair to compare the power of a Chinese rear hub motor watt for watt with a 250W Bosch or Brose or even a Shimano or Yamaha mid-drive motor. There just isn’t even close to the amount of torque or power on a per watt basis and that’s before we get to controllers. However, comparing the Rattan’s 350W motor to the Ancheer’s 250W motor seems more proportionally correct. Where as I could make it about a third of the way up my driveway hill from a cold start on Ancheer throttle, I made it about 2/3rds of the way with the Rattan, or another 100 feet. On a flat surface, again with throttle only, I hit 20 mph in about 10 seconds with the Rattan. It takes me another 5+ seconds to get there on the Ancheer. One note, the battery gauge does bounce around a bit depending on how much it is working. At full throttle you might lose a bar or 2 only to get it back once you coast.
Many countries have enacted electric vehicle laws to regulate the use of electric bicycles. Countries such as the United States and Canada have federal regulations governing the safety requirements and standards of manufacture. Other countries like the signatories of the European Union have agreed to wider-ranging legislation covering use and safety of their term EPAC (electric vehicles)

Further innovations increased comfort and ushered in a second bicycle craze, the 1890s Golden Age of Bicycles. In 1888, Scotsman John Boyd Dunlop introduced the first practical pneumatic tire, which soon became universal. Willie Hume demonstrated the supremacy of Dunlop's tyres in 1889, winning the tyre's first-ever races in Ireland and then England.[28][29] Soon after, the rear freewheel was developed, enabling the rider to coast. This refinement led to the 1890s invention[30] of coaster brakes. Dérailleur gears and hand-operated Bowden cable-pull brakes were also developed during these years, but were only slowly adopted by casual riders.
Federal law defines the limits of a low speed electric bike, equating it to a bicycle, and bypassing the definition of a motor vehicle only “For purposes of motor vehicle safety standards…” which means that the manufacturers of these bicycles don’t have to meet federal equipment requirements, and are instead governed by the manufacturing requirements of the Consumer Product Safety Act. There is no mention of exemption from other federal, state, and local traffic laws, or exemption from the definition of a motor vehicle for other purposes.3 This means the law applies to the manufacturer’s product and sale, avoiding federal safety requirements applying to a motor vehicle such as brake lights, turn signals and braking specifications. The goal of the law was to give businesses a legal framework to define and sell low speed electric bikes without the more stringent Federal classification of a motor vehicle. Ebikes that meet the criteria are considered a “bicycle”, do not meet the definition of a motor vehicle, and will be regulated by the Consumer Product Safety Commission. The law also grants the commission authority to add safety requirements to this product. The Federal law supersedes all state laws that equate bicycles to ebikes where the state law is more stringent (lower limits) on power and speed.
Bicycle manufacturing proved to be a training ground for other industries and led to the development of advanced metalworking techniques, both for the frames themselves and for special components such as ball bearings, washers, and sprockets. These techniques later enabled skilled metalworkers and mechanics to develop the components used in early automobiles and aircraft.
Haibike ships the HardNine with 29-inch tires, 180-millimeter hydraulic disc brakes, a 100-millimeter front suspension fork, and a nine-speed Shimano shifting system. The bike’s LCD readout is affixed to the handlebars and displays the current speed, level of charge, remaining range, and current pedal assist mode. The company says the battery can be completely recharged in just four hours, minimizing downtime between rides.