Yes, there are less expensive ebikes on the market but most come with a few serious caveats. The Espin Sport delivers on the full promise of an electric bike, but in a more affordable fashion. This bike isn’t going to tow you around for a 60-mile round-trip endeavor but those seeking their first ebike will get plenty of return on their investment with this model.
The great majority of modern bicycles have a frame with upright seating that looks much like the first chain-driven bike. These upright bicycles almost always feature the diamond frame, a truss consisting of two triangles: the front triangle and the rear triangle. The front triangle consists of the head tube, top tube, down tube, and seat tube. The head tube contains the headset, the set of bearings that allows the fork to turn smoothly for steering and balance. The top tube connects the head tube to the seat tube at the top, and the down tube connects the head tube to the bottom bracket. The rear triangle consists of the seat tube and paired chain stays and seat stays. The chain stays run parallel to the chain, connecting the bottom bracket to the rear dropout, where the axle for the rear wheel is held. The seat stays connect the top of the seat tube (at or near the same point as the top tube) to the rear fork ends.
Another type of electric assist motor, often referred to as the mid-drive system, is increasing in popularity. With this system, the electric motor is not built into the wheel but is usually mounted near (often under) the bottom bracket shell. In more typical configurations, a cog or wheel on the motor drives a belt or chain that engages with a pulley or sprocket fixed to one of the arms of the bicycle's crankset. Thus the propulsion is provided at the pedals rather than at the wheel, being eventually applied to the wheel via the bicycle's standard drive train.
"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, 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.
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.
Rear-Mounted Hub Motor, installed on the rear wheel, are more common on pre-built bikes because they’re easily installed at the factory. For a conversion, it’s a little harder to install than a front hub motor because of the chain, gearing and derailleur. Plus, you may be limited to a 6 or 7-speed freewheel. However, rear wheel drive will provide more torque and is less noticeable than a front hub.
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.
(2) BICYCLE.--Every vehicle propelled solely by human power, and every motorized bicycle propelled by a combination of human power and an electric helper motor capable of propelling the vehicle at a speed of not more than 20 miles per hour on level ground upon which any person may ride, having two tandem wheels, and including any device generally recognized as a bicycle though equipped with two front or two rear wheels. The term does not include such a vehicle with a seat height of no more than 25 inches from the ground when the seat is adjusted to its highest position or a scooter or similar device. No person under the age of 16 may operate or ride upon a motorized bicycle.
Oklahoma defines an Electric-Assisted Bicycle in 47 O.S. 1-104  as "Two or three wheels; and Fully operative pedals for human propulsion and equipped with an electric motor with a power output not to exceed one thousand (1,000) watts, incapable of propelling the device at a speed of more than thirty (30) miles per hour on level ground, and incapable of further increasing the speed of the device when human power alone is used to propel the device at a speed of thirty (30) miles per hour or more. An electric-assisted bicycle shall meet the requirements of the Federal Motor Vehicle Safety Standards as set forth in federal regulations and shall operate in such a manner that the electric motor disengages or ceases to function when the brakes are applied."
Electric bicycle usage worldwide has experienced rapid growth since 1998. It is estimated that there were roughly 120 million "ebikes" on the road in China as of early 2010.. The “Electric Bikes Worldwide Reports – 2010 Update” estimates that 1,000,000 electric bicycles will be sold in Europe in 2010. The same report estimates that sales in the USA will reach roughly 300,000 in 2010, doubling the number sold in 2009.
You turn it on by pressing the green button on the battery once for low power and twice for high, although to be honest, there is not a lot of difference between them. After that, you just pedal. There are no gears, no chain to muck up your trousers (a motorbike-style carbon fibre belt is used instead) and not that much difference in feeling compared to riding a normal bike.