If you're more concerned with conquering the countryside than the commute, Cyclotricity's Stealth is the one for you. It's a full-size mountain bike, with aggressive tyres and suspension on the front forks to absorb the rocks and bumps on the trails. It's comfortable to ride, and its motor can either give you assistance while you ride, or you can just hit the throttle to rocket over hills with no effort on your part.
On October 22, 2014 PA house bill 573 passed into law, which is Act 154, which changes the definition of "pedalcycle" (bicycle) in the PA state vehicle code. "Pedalcycle" is now defined as a vehicle propelled solely by human-powered pedals or a "pedalcycle" (bicycle) with electric assist( a vehicle weighing not more than 100 pounds with two or three wheels more than 11 inches in diameter, manufactured or assembled with an electric motor rated no more than 750 watts and equipped with operational pedals and travels at speeds less than 20 mph). This bill allows the usage of pedal assisted bicycles in PA that follow the adopted state guidelines.
Battery – in combination with the motor, this determines how far you can get before your bike needs a recharge. Some don’t provide adequate support on even gentle hills, while the best will comfortably take the strain as the gradient shoots up. Range also varies, with the best e-bike systems we’ve tested able to take you nearly twice the distance of lesser models.
European Union directive 2002/24/EC exempts vehicles with the following definition from type approval: "Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25km/h (15.5mph) or if the cyclist stops pedaling." This is the de facto definition of an electrically assisted pedal cycle in the EU. As with all EU directives, individual member countries of the EU are left to implement the requirements in national legislation.
I discovered these downsides when, on my third day with the bike, I got a flat tire and had to carry it onto the subway with me for those last few miles back to my apartment. The cause of the flat is unknown; the bike mechanic who eventually fixed it didn’t see anything wrong with the rims. But the experience of trying to maneuver an almost 40 pound e-bike on and off a crowded subway car during rush-hour is not one I can recommend.
In a friction drive motor, a small, solid wheel rotates against the side of the tire in order to drive it. The first motorcycles used the same concept, with a motor mounted above the front wheel. The problem is that the drive rubs at the side of the tire. It's inefficient, and it quickly wears the sidewall away. Tires need to be replaced every couple hundred miles. For this reason, you'll seldom see electric bikes with this type of drive anymore.
Ontario is one of the last provinces in Canada to move toward legalizing power-assisted bicycles (PABs) for use on roads, even though they have been federally defined and legal in Canada since early 2001. In November 2005, "Bill 169" received royal assent allowing the Ministry of Transportation of Ontario (MTO) to place any vehicle on road. On October 4, 2006, the Minister of Transportation for Ontario Donna Cansfield announced the Pilot Project allowing PABs which meet the federal standards definition for operation on road. PAB riders must follow the rules and regulations of a regular bicycles, wear an approved bicycle helmet and be at least 16 years or older. There are still a number of legal considerations for operating any bicycle in Ontario.
Built around a heavy-duty alloy frame, the GSD eschews many of the traits of other cargo bikes: long wheelbases, bigger wheels, and especially, an unwieldy ride. Yet it boasts an extensive capacity, nimble handling—even fully loaded, thanks to a short wheelbase and 20-inch wheels—and enduring range in a package not much bigger than most non-cargo e-bikes. The stout frame holds a 250-watt Bosch motor that gives up to 275 percent of your power back to the pedals and reaches 20 mph. The GSD has room for two battery packs, extending the batteries’ combined range to a claimed 150 miles and making the Tern one of the longest-lasting e-bikes on the market. A laundry list of accessories and a (claimed) 396-pound carrying capacity round out the GSD’s status as an epic day-tripper.
In Quebec power-assisted bicycles are often classified similarly to standard pedal bicycles. They do not have to meet the conditions defined within the Canadian Motor Vehicle Safety Regulations (they are not classed as "motor vehicles"), but they do have to comply with federal regulations that define Power Assisted Bicycles. The Quebec Highway Safety Code defines a power-assisted bicycle as a bicycle(2 or 3 wheels that touch the ground) with an electric motor with a maximum power of 500W and a top speed of 32 km/h bearing a specific compliance label permanently attached by the manufacturer. PABs are permitted on the road in the province of Quebec, but riders have to be 14 and over to ride the electric bicycle and if they're under the age of 18, must have a moped or scooter license.
Most electric bicycles can be locked using keys supplied by the manufacturer. The key is usually inserted into a switch, which is commonly found on the bicycle's handlebars or on one side of the motor compartment. When switched to the "Off" position, the electrical drive system cannot be turned on. In areas of high risk for bicycle theft, these locking mechanisms are used in conjunction with coil or U locks.
The Super Commuter is very aptly named. The 350w Bosch motor will help you sustain speeds of up to 28mph, and the burly, 2.4-inch wide, Schwalbe Super Moto-X 650b tires will keep you secure on even the roughest city streets, and Shimano Deore hydraulic brakes provide ample stopping power. Fenders provide welcome protection from road spray so you arrive at your destination fresh, integrated lights are critical for post-sunset riding, and a side-view mirror hanging on the left side of the handlebar gives a great view of traffic around you. After all, you can ride at the speed of urban traffic on the Super Commuter.
October 5, 2009 — Ontario is bringing in some new safety requirements for electric bikes. E-bikes, which can reach a speed of 32 kilometres per hour, are allowed to share the road with cars, pedestrians and other traffic throughout the province. The new rules limit the maximum weight of an e-bike to 120 kilograms, require a maximum braking distance of nine metres and prohibit any modifications to the bike's motor that would create speeds greater than 32 kilometres per hour. Also, riders must be at least 16 years of age, wear approved bicycle or motorcycle helmets and follow the same traffic laws as bicyclists. Municipalities will be able to decide where e-bikes may be used on their streets, bike lanes and trails. E-bikes will not be permitted on 400-series highways, expressways or other areas where bicycles are not allowed. Riding an e-bike under the age of 16 or riding an e-bike without an approved helmet carries fines ranging from $60 to $500. For all other traffic offences, e-bike riders will be subject to the same penalties as cyclists.
Conversion kits, on the other hand, are sold and installed separately on traditional bicycles. They are harder to setup and conceal, and require some basic mechanical ability and a little bit of ‘elbow grease’ to install. The advantage of conversion kits is that you can choose almost any standard bicycle, and you have the freedom to change or upgrade components as you go. A conversion kit will also allow you to achieve higher power and speed ratings that are not possible on most pre-built electric bike models. Kits are great for tall or heavy riders because they can opt for a larger bike, with higher power and weight carrying capacity. People living in hilly terrain may require the additional torque to handle extremely large inclines. For people who prefer a specific bike model or just love to go faster, a conversion kit offers enormous flexibility.
They also served to teach the industrial models later adopted, including mechanization and mass production (later copied and adopted by Ford and General Motors), vertical integration (also later copied and adopted by Ford), aggressive advertising (as much as 10% of all advertising in U.S. periodicals in 1898 was by bicycle makers), lobbying for better roads (which had the side benefit of acting as advertising, and of improving sales by providing more places to ride), all first practiced by Pope. In addition, bicycle makers adopted the annual model change (later derided as planned obsolescence, and usually credited to General Motors), which proved very successful.
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!
Power assisted bicycles are classified in two categories in Saskatchewan. An electric assist bicycle is a 2 or 3 wheeled bicycle (sic.: 3 wheeled bicycle) that uses pedals and a motor at the same time only. A power cycle uses either pedals and motor or motor only. Both must have engines with 500 watt power or less, and must not be able exceed 32 km/h (20 mph), i.e., electric motor cuts out at this speed or cycle is unable to go this fast on a level surface. The power cycle has to meet the Federal Motor Vehicle Safety Standards for a power-assisted bicycle. The power cycle requires at least a learner's driving licence (class 7), and all of the other classes 1-5 may operate these also. The electric assist bicycle does not require a licence. Helmets are required for both. Both are treated as bicycles regarding rules of the road. Gas powered or assisted bicycles are classified as motorcycles regardless of engine size or if using pedals plus motor. Stickers identifying the bicycle's compliance with the Federal classification may be required for power cycles by some cities or municipalities. 
E-bikes mostly use motors and battery options from a few major suppliers: Bosch, Yamaha, Shimano, and Brose. A few other brands exist, but are less reliable or powerful. Some, like the Yamaha system, have more torque, and others, like Bosch’s Active Line, are nearly silent. But, generally, all four make good options. Look for motor output (in torque), which will give you an idea of total power. Just like car engines, more torque equals more power off the line and more boost to your pedaling. But watt hours (Wh) is perhaps a more important figure to use—it takes into account battery output and life to give a more accurate reflection of power (higher Wh equals bigger range).
Great question… a real world situation from someone doing their best to follow the law but also be realistic about time/distance. What follows is my opinion on the matter based on lots of electric bike riding experience, this is not legal advice. You can probably ride with electric assist across the dirt way with no issues and avoid any negative response that might arise as long as you’re polite to other cyclists and pedestrians and pedal along without going too fast. If someone called you out about it you could easily hop off, walk your bike and explain that you use the assist to help make your commute possible or possibly, like me, you have a knee injury and it’s difficult to pedal through softer terrain like gravel. Another different approach might be to shut the bike off completely before entering the gravel section, you could even take the battery off and put it in a backpack or as mentioned earlier… just walk the bike. Imagine if you had a motorized dirt bike and were just pushing it along a sidewalk… this kind of vehicle definitely is not allowed on sidewalks or most gravel paths like the one you’re describing but if you were escorting it carefully, you’d be honoring the spirit of the law and if an officer or pedestrian jumped out and started questioning you about your “motorized vehicle” it is my feeling that a genuine explanation and apology or request for guidance would go very well. I personally have never had issues riding electric bikes in part because I am thoughtful about how I use them. I do occasionally switch them off and sometimes I get off and walk. I have asked police in many cities across the US what they thought about ebikes and in every case I have received positive interest and support with guidance to ride safe with a helmet and follow traffic laws in the street. I hope this helps and I wish you well, it’s nice that you care enough to ask and I hope you’re treated well by others out on the road. The flip side of this response is that I have been harassed, yelled at and even swerved at by automobiles when riding bicycles and electric bikes. This usually happens in the evening after work lets out when traffic is heavy and I’m riding on the shoulder or in the street (where marked to do so) and I believe it has to do with territory, testosterone and socio-economic standing more so than laws or anything like that.
I bought the 52v 13ah for my 1000w BBSHD build and it is working great. My bike tears it up pretty good with this battery pack. Hopefully I don't run into any problems but so far so good. One thing I learned the hard way - if you use a 52v pack with the 1000w bbshd your battery meter will no longer be accurate. That was one tough ride home with my heavy fat bike!
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.