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.
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.
Rose Heyer and Josie Tabor of Dept Tech, Department of State Information Center, the Secretary of State and the office of ROCK AND BORGELT, P.C., Attorneys at Law, 24500 FORD ROAD, SUITE 10 DEARBORN HEIGHTS, MI 48127-3106, determined electric bicycles are considered mopeds and need registered and licensed. In order to operate an electric bicycle on public streets, the driver must have a valid operator, chauffeur, or special moped license. However, not all electric bicycles are street legal unless they have the following safety equipment: operating brake light, headlight, and turn signals. The local police department must inspect the bicycle using Form TR-54 which is taken with proof of purchase to the DMV. The fee for the plate is $15 for a three year decal, whereas the fine for no decal is $150 per incident.
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. The rules for e-bikes on public roads, sidewalks, and pathways are under state jurisdiction, and vary.