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.
E-bikes are zero-emissions vehicles, as they emit no combustion by-products. However, the environmental effects of electricity generation and power distribution and of manufacturing and disposing of (limited life) high storage density batteries must be taken into account. Even with these issues considered, e-bikes are claimed to have a significantly lower environmental impact than conventional automobiles, and are generally seen as environmentally desirable in an urban environment.[65]
Because the power is applied through the chain and sprocket, power is typically limited to around 250–500 watts to protect against fast wear on the drivetrain. An electric mid-drive combined with an internal gear hub at the back hub may require care due to the lack of a clutch mechanism to soften the shock to the gears at the moment of re-engagement. A continuously variable transmission or a fully automatic internal gear hub may reduce the shocks due to the viscosity of oils used for liquid coupling instead of the mechanical couplings of the conventional internal gear hubs.
To operate the bike, you have to pedal for a second or so before the thumb throttle becomes active. This is often a cost and energy-saving measure designed into electric bicycles and scooters. Being able to start the motor from rest requires extra sensors and higher battery power. Starting the motor while it is in motion removes the need to install extra sensors in the motor (and thus removes one more possible failure or maintenance issue) and also eeks more range out of the battery by putting the energy intensive initial startup responsibility solely on the rider.
Electric motor assisted bicycles have been banned in the State of New York and are not permitted for on-road use.[50][51] It appears the only known allowance of an electric bicycle is if it is an electric powered moped, at this time. There is a proposed bill to allow ebikes. As of May 2009, Bill A2393("Defines the term electric assisted bicycle") has been passed in the NY State Assembly[52] and its corresponding Bill S4014, sponsored by Senator Thomas Morahan, is before the NY State Senate.[53]
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.
What I found most interesting is how my cycling habits changed over my two weeks with the eBike, mostly for the better. In most states, cyclists need to come to a complete stop at stop signs... and as anyone who has ever ridden a bike or shared a road with a cyclist knows, most cyclists generally do an Idaho Stop if they believe it's safe. I do it, too. Knowing that I could quickly get back up to speed with the aid of the electric motor, I found myself more willing to sacrifice my forward momentum and come to a complete stop when there was a car approaching an intersection.
Besides voltage, batteries are rated by amp hours (AH). Although voltage seems to get the most attention, the amp hour rating of the battery is just as important. It is the measure of a battery’s capacity and provides a good indication of the range you can expect from an electric bike. Although lots of factors come into play in determining range (ie: rider weight, terrain, input, efficiency, etc.), a good rule of thumb is range is equal to AH. So under normal conditions, an average rider can expect 10 miles out of a 10AH battery (with no pedaling). With rider input, this number can be dramatically increased, so most 10AH batteries are rated “up to 20 miles” by the manufacturer which assumes pedaling. On pedal-assist bikes (which require pedaling), the range ratings are much higher because the rider is constantly assisting the motor and reducing the current draw.

Seth Miller said he founded the company after his first electric bike was stolen from where it was parked in front of the midtown office building where he worked. The company that manufactured the bike had disbanded, so he started researching different suppliers. He soon discovered that a majority of the e-bikes sold in the US are just cobbled together from a variety of off-the-shelf Chinese-made parts found in a catalog. It sounded simple, so Miller figured he’d try it himself.


The batteries are the most important parts of the bike, because (if you don't do any pedaling) they contain all the power that will drive you along. Typical electric bike batteries make about 350–500 W of power (that's about 35–50 volts and 10 amps), which is about a quarter as much as you need to drive an electric toaster. In theory, you could use any kind of battery on a bicycle. In practice, however, you want to use something that stores lots of power without being too heavy—or you'll be using half your power just moving the battery along! That tends to rule out heavy lead-acid batteries like the ones that start cars, though some electric bikes do use them. Lightweight lithium-ion batteries, similar to those used in laptop computers, mobile (cellular) phones, and MP3 players, are now the most popular choice, though they're more expensive than older rechargeable battery technologies such as nickel-cadmium ("nicad"). Typical batteries will give your bicycle a range of 10–40 miles between charges (depending on the terrain) and a top speed of 10–20 mph (which is about the maximum most countries allow for these vehicles by law). You can extend the range by pedaling or free-wheeling some of the time.
What we especially love is how quiet this e bicycle is. If you’re riding down the street or through the park, the gentle hum of the motor is unnoticeable. This is because it’s hidden by the sound of your smooth pedaling. If you’re not into flashy gadgets, any ordinary person would assume you’re riding a conventional peddle bike. This is a great commuter bike.
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.

Class 1 makes great inroads to establish set boundaries for off road/natural surface trail access for eMountain bikes. There is fierce resistance from some mountain biking purists to allow ebikes on trails. BPSA and IMBA have done good work to justify the impact of class 1 ebikes on natural surface trails, and eliminate the wear-n-tear argument, though IMBA members are not 100% on board.

Mid-mounted system means that the electric motor is not built into the wheel but is usually mounted near (often under) the bottom bracket shell. Mid-drive systems tend to feel more like a normal bike, since they drive the pedals, just like your legs, and those who frequently climb long, steep hills tend to prefer mid-drive systems for their ability to handle long climbs. As they can leverage the bicycles lowest gears for climbs, mid drive systems can also leverage the high gears to reach higher speeds on flat areas than a hub system. The mid-drive motor drives the crank, instead of the wheel itself, which multiplies its power and allows it to better take advantage of the bike’s existing gears. If the rider changes the gears appropriately, the motor can turn closer to its ideal rotations per minute which makes a huge difference while climbing hills, so this is a perfect option for those who love mountain biking.
During the course of its evolution, the Specialized Levo has helped shape the world of eMTBing. When it was introduced, it set the benchmark in riding dynamics and integration. Now Specialized has completely redesigned the bike and put it on 29″ wheels. The integration has been improved yet again, the battery capacity has been increased and the handling has been refined. We were thrilled with our first test ride. Anyone looking for a new bike next year for maximum trail performance should definitely take a closer look at the new Levo! We’re already looking forward to our big group test of the best bikes of 2019 early next year.

In the theoretical electric bike we considered up above, we had the dynamo/motor driving the back wheel directly, simply by pressing on the tire. Most electric bikes work a different way. They have compact electric motors built into the hub of the back or front wheel (or mounted in the center of the bike and connected to the pedal sprocket). Take a look at the hub of an electric bike and probably you'll see it's much fatter and bulkier than on a normal bike. You can read more about how these motors work in our main article about hub motors.

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