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.
"Medical Exemptions" are also a standard right in the State of Texas for motorcycles & even bicyclists. Through Texas's motorcycle helmet law (bicycle helmet laws from city ordinances), it is only required for those 21 years old or younger to wear a helmet. However, a medical exemption, [59][60][61][62][63][64] written by a certified licensed medical physician or licensed chiropractor, which exempts one from wearing a helmet, can be used for bicyclists if helmets are required.
This dexterous electric dirt bike is recommended for anyone over the age of 14. It’s fitted with double suspension and big tyres to help you tackle tough terrain. You also get a good selection of gears, that gives you optimal control. The Razor can go as fast as 15 mph on average, and comes with an excellent braking system. The aesthetics are on point, and the racer look is sure to impress. Don’t forget your helmet!
Both the Stromer and the Stoeckli are very nice looking designs and easy to handle. Reliability for both does not seem to be up to Swiss standards, e.g. some of the 2012 Stöcklis seem to have bad contacts. However, as of 2013, most of these problems should be fixed. The Cube got criticized for its battery/saddle system, but this has probably been fixed in more recent edition and it has less "punch" then the other's since the motor is smaller (324W?). I don't know about the BH Neo Nitro. Given the relatively low price of the BH Nitro, it may be the best buy in this category if you plan to cover smaller distances (the battery is limited to 9Ah, and Spain's industry does need some help ;) Anyhow, all of these models come with a variety of motors and country-specific modifications. E.g. in France, the BH Nitro comes with a 350W motor and is electronically limited to 25km/h, whereas in Switzerland you either can get a 500W - 45 km/h version or a 250W? - 25km/h version.

Great bike. Easy to assemble by yourself but if you have a rack let pros do it. No charge for that. Contacted the Addmotor people a few times and they got back quickly even on weekends. Great service. Bike is solid as a rock and excellent components. Only drawback is lack of fenders which I hope someone can manufacture. I would buy again in a nano second!
I called Geico earlier today. They could insure me with Renters Insurance, but … I would need to have a Renter's Policy first, before the secondary insurance company they deal would insure my two bikes (Surly Long Haul Trucker and Yuba Sweet Curry custom eBike). BUT … unfortunately …. The company that would insure my bicycles will NOT insure me because we have a Pitbull !!! Can you believe that … !!!
Maryland defines an "electric bicycle" as a vehicle that (1) is designed to be operated by human power with the assistance of an electric motor, (2) is equipped with fully operable pedals, (3) has two or three wheels, (4) has a motor with a rating of 500 watts or less, (5) and is capable of a maximum speed of 20 miles per hour on a level surface when powered by the motor. (Senate Bill 379, approved by the Governor 5/5/2014, Chapter 294.) [96] This legislation excludes "electric bicycle" from the definition of "moped", "motorized minibike", and "motor vehicle", and removes the titling and insurance requirements required for electric bicycles under prior Maryland law.
"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],
Indian law requires that all electric vehicles have ARAI[50] approval. Vehicles with below 250W and speed less than 30 km/h, do not require certification- hence not following full testing process, but needs to get exemption report from ARAI. Whereas more powerful vehicles need to go through a full testing process following CMVR rules. This can take time and cost money but assures safe and reliable design for Electric Vehicles. These regulations are not promulgated by the Regional Transport offices, and riders are not required to obtain a licence to drive, to carry insurance, or to wear a helmet.
In Norway, e-bikes are classified as ordinary bicycles, according to the Vehicle Regulation (kjøretøyforskriften) § 4-1, 5g. Hence, e-bikes are not registered in the Vehicle Registry, and there is no demand for a license to drive them. Still, there are constraints on the bicycle construction. The maximum nominal motor power output can be no more than 250 watts and the maximum performance speed of the vehicle when the engine is running is 25 km per hour (15 mph).[40] A function that reduces motor power when vehicle speed exceeds 25 km per hour is mandatory. However, if the motor is not running, the e-bike, or any other bike, answer only to the constraints of the ordinary speed limits.
And let’s not forget the economic advantages of owning an e-bike. The annual cost of running a new family car is, on average, about $9,000 per year. Running an electric bike costs around $400 per year. And while filling a gas tank costs around $30, recharging an electric bike battery costs only about 50 cents. A tank of gas may get you further, but not 60 times further!
To qualify as an electric-assisted bicycle under state law they need to have a seat and fully operable pedals for human propulsion, meet federal motor vehicle safety standards, an electric motor that has a power output of not more than 1,000 watts, maximum speed of not more than 20 mph (electric motor and human power combined), disengages or ceases to function when the vehicle’s brakes are applied, two or three wheels

I do not recommend hacking a bike into s-pedelec, i.e. make a 25km/h bike go at 45 or faster. If you have an accident you will be in trouble. Just get a legal version. In addition you will have good insurance. Of course, in countries like France or the UK that so far do not know S-Pedelecs, you will have to make a difficult moral choice.... At least, make sure that your rig is safe...

Bicycles featuring pedal power were developed during the subsequent decades of the 19th century, with the most emblematic example being the bicycle we know today as the Penny-Farthing. The bike was named based on the substantial difference in its wheel size resembling the larger and smaller Penny and Farthing coins, respectively. These bicycles were wildly popular among the well heeled upper classes of Europe and America despite their penchant for launching riders head first over the large wheel, not to mention their relative difficulty to mount and dismount.

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.
However, Emu sells a little foldable number if that's your bag. The Emu Crossbar is for  town commuters that require a sweet ride that's backed up by solid Shimano Nexus hub gears and Tektro brakes, which are adequate if not the best on the market. Riding is smooth and easy, with the crank moving sensor doing its best to iron out any gaps in power delivery.
I would advocate you ride legal within the laws of your state. I would also look into some kind of liability rider or umbrella policy with your home owner’s policy, which covers your personal liability and theft. Get your bike registered; wear your helmet, eye protection, whatever is required by state law so that if an accident occurs and you are at fault, there is no legal recourse. Even if you own a 750W/20mph ebike that meets the definition of a bicycle, any at-fault cyclist may still be denied coverage by stingy insurance companies who want to support their clients. Your health insurance will usually cover your medical bills, but the costs of an expensive ebike may be lost.

In 2012, two e-bike advocates completed the first 4,000-mile (6,400 km) transcontinental e-bike tour from New York to San Francisco to advocate for e-bikes in major cities across the U.S.[81] Pedego Electric Bikes is the best selling brand in the U.S. Many e-bikes in the United States are standard bicycles converted using a kit. In general, the kits include the motor (the majority of which are hub motors built into the front or rear wheel), a speed controller, throttle (usually twist-grip or thumb throttle), necessary wiring and connectors, and a battery. Several U.S. companies offer conversion kits which also offer advanced lithium battery packs. Major manufacturers also offer complete e-bikes. Trek offers a line of e-bikes using the Bionx system in which the rider programs the controller to determine how much effort the motor will give in response to rider effort, from 25% up to 200% of the rider's power. This system ensures a minimum level of rider participation and is also used to comply with many European laws mandating partial human effort before the motor engages.
This slick-looking commuter features a clean and quiet Gates Carbon Drive belt, which eliminates the maintenance that comes with a derailleur, and an internally geared Enviolo Trekking hub, which provides a 380 percent gear range. The Embark has 650b wheels, 47mm WTB gumwall tires, full fenders with mudflaps, and integrated lights—meaning you can ride long after the sun sets—or before it rises. A Bosch Active Line Plus mid-drive motor is light and quiet and provides pedal assist up to 20 mph, and the Bosch 400Wh battery has a claimed range of 50 miles. Everything about the Embark frame screams clean, stylish, and organic.
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.
Range is a key consideration with e-bikes, and is affected by factors such as motor efficiency, battery capacity, efficiency of the driving electronics, aerodynamics, hills and weight of the bike and rider.[36][37] Some manufacturers, such as the Canadian BionX or American Vintage Electric Bikes,[38] have the option of using regenerative braking, the motor acts as a generator to slow the bike down prior to the brake pads engaging.[39] This is useful for extending the range and the life of brake pads and wheel rims. There are also experiments using fuel cells. e.g. the PHB. Some experiments have also been undertaken with super capacitors to supplement or replace batteries for cars and some SUVS. E-bikes developed in Switzerland in the late 1980s for the Tour de Sol solar vehicle race came with solar charging stations but these were later fixed on roofs and connected so as to feed into the electric mains.[40] The bicycles were then charged from the mains, as is common today. While ebike batteries were produced mainly by bigger companies in past, many small to medium companies have started using innovative new methods for creating more durable batteries. State of the art, custom built automated precision CNC spot welding machines[41] created 18650 battery packs[42] are commonly used among Do-it-yourself ebike makers.
In cities where bicycles are not integrated into the public transportation system, commuters often use bicycles as elements of a mixed-mode commute, where the bike is used to travel to and from train stations or other forms of rapid transit. Some students who commute several miles drive a car from home to a campus parking lot, then ride a bicycle to class. Folding bicycles are useful in these scenarios, as they are less cumbersome when carried aboard. Los Angeles removed a small amount of seating on some trains to make more room for bicycles and wheel chairs.[65]
Simple, convenient, cheap, and economical—bicycles are one of the world's favorite forms of transportation. But they're not for everyone. They can be hard to pedal up and down hills or with heavy loads, and elderly or disabled people may find them impossible to manage. In the last few years, a new generation of electric bicycles has begun to revolutionize our idea of environmentally friendly transportation. These new cycles have all the convenience of cars with all the simple economy of ordinary cycles. Let's take a closer look at how they work.