Some countries require child and/or adult cyclists to wear helmets, as this may protect riders from head trauma. Countries which require adult cyclists to wear helmets include Spain, New Zealand and Australia. Mandatory helmet wearing is one of the most controversial topics in the cycling world, with proponents arguing that it reduces head injuries and thus is an acceptable requirement, while opponents argue that by making cycling seem more dangerous and cumbersome, it reduces cyclist numbers on the streets, creating an overall negative health effect (fewer people cycling for their own health, and the remaining cyclists being more exposed through a reversed safety in numbers effect).[citation needed]
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).
In addition the specific wording of the law may or may not prohibit the use of a "mid-drive" or "crank-drive" motor set-up where the motor drives the rear wheel of the bicycle through the existing chain drive of a bicycle that has multiple gears depending on several points of interpretation of the law. Specifically the interpretation of the wording, "does not require clutching or shifting by the operator after the drive system is engaged". A "mid-drive" or "crank-drive" motor set-up on an electric bicycle does indeed allow the operator to change gears in the power drive system between the motor and the rear wheel of the bicycle. Whether or not such a mechanism which allows the operator to change gears satisfies the wording that requires the operator to change gears is a matter of legal interpretation by the courts. Just as "shall issue" and "may issue" (as in laws governing the issuing licenses) in application of the law have two different meanings (in the first case if you meet the requirements they have to give you the license and in the second they don't have to if they decide not to even if you meet the requirements for the license) whether or not "does not require shifting" outlaws electric bicycles where shifting is possible but is not necessarily required is a matter of interpretation. Thus the legality of electric bicycles equipped with a "mid-drive" or "crank-drive" motor set-up in the U.S. state of Montana is not clearly defined.
Play it Safe, Make it Easy – E-bike manufacturers will offer you a large variety of styles, types, colors and utility, but the base specifications will be a bike producing less than 750 watts of power (1 horsepower = 746W) , and have its speed limited to 20mph on motor power alone. The majority of US ebikes meet that specification. Manufacturers do this for their own liability. Going this route assures you that your bike was built and sold legally. As a result, you will have about every privilege that a normal bicycle can expect. However, state and local laws may dictate reduced speeds and limited access to bike paths.
Historically, women's bicycle frames had a top tube that connected in the middle of the seat tube instead of the top, resulting in a lower standover height at the expense of compromised structural integrity, since this places a strong bending load in the seat tube, and bicycle frame members are typically weak in bending. This design, referred to as a step-through frame or as an open frame, allows the rider to mount and dismount in a dignified way while wearing a skirt or dress. While some women's bicycles continue to use this frame style, there is also a variation, the mixte, which splits the top tube laterally into two thinner top tubes that bypass the seat tube on each side and connect to the rear fork ends. The ease of stepping through is also appreciated by those with limited flexibility or other joint problems. Because of its persistent image as a "women's" bicycle, step-through frames are not common for larger frames.
Electric bicycles use batteries as a source of power and a quiet DC motor as a driving mechanism. On most e-bikes the motor is built directly into the wheel (known as a hub motor) and the batteries are discreetly hidden in the rear rack or frame. Electric bikes can be operated just like normal bicycles, but they can also be power-driven by a throttle or pedaled with the help of pedal-assist (PAS or pedelec).
The federal Consumer Product Safety Act defines a "low speed electric bicycle" as a two or three wheeled vehicle with fully operable pedals, a top speed when powered solely by the motor under 20 mph (32 km/h) and an electric motor that produces less than 750 W (1.01 hp). The Act authorizes the Consumer Product Safety Commission to protect people who ride low-speed electric vehicles by issuing necessary safety regulations.[63] The rules for e-bikes on public roads, sidewalks, and pathways are under state jurisdiction, and vary.
Most European bike rules are tight and restrictive. Right now the California state ebike rules in AB 1096 provide the clearest and cleanest format, and they support ebike riding. No other U.S. regulations come close. The big brand ebikes (Giant, Specialized, Trek) are selling bikes that fit within European rules (250w-300w motors). This gives them economies of scale. 

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.
All classes of electric-assisted bicycles may be operated on a fully controlled limited access highway. Class 1 and 2 electric bicycles can be used on sidewalks, but Class 3 bicycles "may not be used on a sidewalk unless there is no alternative to travel over a sidewalk as part of a bicycle or pedestrian path."[143] Generally a person may not operate an electric-assisted bicycle on a trail that is designated as non-motorized and that has a natural surface, unless otherwise authorized.
Powered by a 250-watt Brose Centerdrive system, the Redux is capable of reaching speeds of up to 28 mph, which comes in handy when dodging traffic. The lithium-ion battery provides enough juice to give the bike a range of up to 80 miles between recharges, making it a great option for daily commuters. Raleigh even outfitted the bike with wide tires which provide stability and traction, even when the road gets wet. Other key features include a 10-speed Shimano crankset and shifters and a built-in LCD screen that displays all the usual information.
The body is made from light and durable aluminum. The handlebar comes with simple controls to let you accelerate, brake, monitor battery life, operate headlights and of course…sound the horn. There’s even an USB point that will let you charge your iPhone or Android on the go. The bike can reach a top speed of 10mph. Feel the wind in your hair as you zoom up and down hills and past all that city traffic…
Another style is the recumbent bicycle. These are inherently more aerodynamic than upright versions, as the rider may lean back onto a support and operate pedals that are on about the same level as the seat. The world's fastest bicycle is a recumbent bicycle but this type was banned from competition in 1934 by the Union Cycliste Internationale.[43]
Beginning January 1, 2017, manufacturers and distributors of electric bicycles will be required to apply a label that is permanently affixed, in a prominent location, to each electric bicycle, indicating its class. Should a user "tamper with or modify" an electric bicycle, changing the speed capability, they must replace the label indicating the classification.
Bicycles are popular targets for theft, due to their value and ease of resale.[113] The number of bicycles stolen annually is difficult to quantify as a large number of crimes are not reported.[114] Around 50% of the participants in the Montreal International Journal of Sustainable Transportation survey were subjected to a bicycle theft in their lifetime as active cyclists.[115] Most bicycles have serial numbers that can be recorded to verify identity in case of theft.[116]

The pedals on a motorised bicycle must be the primary source of power for the vehicle. If the motor is the primary source of power then the device cannot be classed as a motorised bicycle. For example, a device where the rider can twist a throttle and complete a journey using motor power only without using the pedals, would not be classed as a motorised bicycle.
"Bicycle" means either of the following: (1) A device having two wheels and having at least one saddle or seat for the use of a rider which is propelled by human power. (2) A device having two or three wheels with fully operable pedals and an electric motor of less than 750 watts (one horsepower), whose maximum speed on a paved level surface, when powered solely by such a motor while ridden, is less than 20 miles per hour.[citation needed],
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.

DON'T BUY THIS BIKE!!!!! Worst customer service ever!!! I bought this bike for my 18 year old son to commute to school. It worked well for the first 2 months but the battery is cheap and stated to wear out. I tried going on the website, but they battery shows as out of stock, and has been for 3 months now. I left 5 emails with customer service, never got a reply. Also there is no number listed on their website to even speak to a real person. Now I have a worthless 5 month old bike..... horrible this company should be ashamed.

I'm wondering if renter's insurance will cover my eBike while I'm out cycling around town to work, shopping, or even on long distance eBike tours ….. And what exactly will the insurance cover … only the bicycle …. all of the extra features …. gadgets … gear ….. This beast will cost me around $9,500.00 (US) when finished. At times I will be carrying as much as $3,000.00+ worth of gear !!!

It's a solid e-bike, but it's also very heavy one for a folding bike. I found it difficult carry when the bike is folded as the carrying handle is useless, and the center of gravity is towards to the rear wheel so one has to find a place in the rear of the bike to pick it up. Even when the bike is folded, it's bulky and heavy, It's difficult to walk with it while carrying it. It's easy to hurt one's back if he or she is not careful. I would not recommend carrying this bike up or down stairways.
The last 8 months we've been wrapping up some long duration testing of Statorade across different hub motor lines and performing experiments confirming its long term stability. These results have us pumped to introduce this motor cooling solution beyond DIY'ers and into wider markets. As an example, have a look at the video we below showing the effect this has on a small direct drive folding bike motor.

State and Local Laws dictate your use, but cannot constitutionally supersede the federal law – Any ebike purchased within the 750W/20mph limits has no fear of being under federal motor vehicle classification, nor can any state classify them a motor vehicle. The ebike is considered a ‘bicycle’ for consumer purposes. However, the State Laws on local bike paths and local thruways may prohibit or limit ebike access. When bike path signs use word such as ‘motor vehicles’ and ‘motorbikes’ , the laws are likely referring to gas-ICE motorbikes/dirt bikes/scooters, and not ebikes. Other references to ‘motorized bicycles’ or ‘motorized vehicles’ sound more inclusive and probably are intended for either ebikes or gas mopeds. If in doubt, you always have the option to pedal unassisted by completely powering your bike down. Even though Federal law grant ebikes a bicycle status, the common consensus found in my research allows local and state law to add additional regulation to pathway and road access, just because “it has a motor”. So the Federal laws protects the consumer from the burden of motor vehicle requirements, but not the restrictions to local and state right of ways enjoyed by all non-motored bicycles.
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.
An electric bicycle also known as an e-bike is a bicycle with an integrated electric motor which can be used for propulsion. Many kinds of e-bikes are available worldwide, from e-bikes that only have a small motor to assist the rider's pedal-power (i.e., (pedelecs) to somewhat more powerful e-bikes which tend closer to moped-style functionality: all, however, retain the ability to be pedalled by the rider and are therefore not electric motorcycles.
The Class 3 Aventon Pace 500 urban e-bike has five levels of pedal assist and tops out at 28 mph. But the Pace has something not found on a lot of modern e-bikes. In addition to pedal power, it also has a throttle—in the case of the Pace, a small thumb paddle on the left side of the handlebar next to the control unit that holds at a steady 20 mph, no pedaling required. The bike itself has an aluminum frame, a swept-back handlebar, ergo grips, a sturdy kickstand, hydraulic disc brakes, 8-speed Shimano Altus shifting and gearing, 27.5x2.2-inch Kenda e-bike-rated tires, a saddle the size of Texas, and good ol’ classic city/commuter-bike geometry. It doesn’t come equipped with fenders or a rear rack, but you can add them. Power comes in the form of a 500-watt rear-hub motor, a semi-integrated battery on the down tube (with a range of up to 50 miles), and a backlit display unit mounted on the stem.
Every bike on this list has been thoroughly evaluated and vetted by our team of test editors. We research the market, survey user reviews, speak with product managers and engineers, and use our own experience riding these bikes to determine the best options. Our team of experienced testers spent many hours and miles using these bikes for their intended purpose. We’ve commuted to and from work on them, used them to stock up on groceries and beer, tested their passenger-hauling capability, ridden them on questionable terrain (just to see how they’d handle), and run their batteries down to officially see how long they last on one charge. We evaluated them on performance, price, comfort, handling, value, reliability, fun, and overall e-factor to come up with this list of bikes that will best serve the needs of anyone looking to add a little pedal assist to their ride.
This thing is also kitted out with a full SRAM groupset, RockShox Yari RC front shocks, Custom Fox Float suspension at the rear and enormously punchy SRAM disc brakes at the front and rear. Fundamentally, it's a mighty off-road machine with pro-spec kit that introduces a new style of trail riding, allowing adrenaline junkies to ride further, climb harder and descend faster than ever before.
Earlier UK regulations required that the motor has an average power output limited to 200 W (250 W for tricycles and tandems) and weight limited to 40 kg (60 kg for tricycles and tandems). These regulations must come in-line with the EU regulations by (find deadline). For models sold before June 2003, e-bikes conforming to the speed, weight and power limits may also be considered pedal cycles. Electric bikes with higher power outputs, or those not meeting the "pedelec" definition are now treated as motorcycles and require a license.
Electric-assisted bicycles are treated as human-powered bicycles, while bicycles capable of propulsion by electric power alone face additional registration and regulatory requirements as mopeds. Requirements include electric power generation by a motor that cannot be easily modified, along with a power assist mechanism that operates safely and smoothly. In December 2008, The assist ratio was updated as follow: 
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