Gearless (Direct-Drive) Hub Motors – Some conversion kits (and bikes) use gearless, direct-drive motors. On this type of motor, the axle that passes through the center of the motor is actually the axle of the motor itself, with the copper windings fixed to the axle. The magnets are mounted to the outer shell of the hub motor. When electricity is applied to the stator a magnetic field is induced that causes the magnets to move. This in turn makes the whole shell of the motor turn and propels the e-bike forward. Even though corrosion will eventually have an impact, this type of motor should last for years since there’s no gearing and no contact between moving parts. They’re also capable of higher top speeds. But since there’s no gears, they have less torque and it requires more power to get the motor up to speed. Most direct-drive hub motors are 350w-500w and reach speeds of 18-25 mph. But more powerful motors can reach speeds of 35+ mph.
While the first functional battery was developed in the year 1800 by Italian physicist Alessandro Volta, a practical battery would not be seen for several decades yet. By the end of the 19th century, practical and portable batteries were more widely available, this finally freeing the electric motor to be used in a wide new array of applications. It might come as a surprise, but the electric motor, battery, and a bicycle were first paired as far back as the 1890s. It would be approximately 100 years later that electric bicycle development finally entered the mainstream, but the technology and concept behind the electric bike were all in place generations ago.
At 42 pounds for a size medium frame (exceptionally light for an urban e-bike), this step-through model’s silent, mid-drive Bosch Active Line motor provides pedal assist up to 20 mph. And its 400Wh battery lasts a claimed 30 to a whopping 110 miles, depending on mode, speed, terrain, rider weight, cargo—all the usual stuff. With 26-inch wheels, 2-inch tires, round aluminum tubes, a swept-back handlebar, Shimano Sora 9-speed components, and an 11-32 cassette, the Parkway looks like an everyday, non-motorized city bike at first glance. But with an array of Bosch e-components—motor, battery, and Purion display—it has the zip to take you farther faster.
When I finally had the ability drive this thing in my city, it feels fantastic, you're cruising easily. But the minute it starts going up a hill, you also gotta peddle to help it go up. Which is okay because the little engine helps a lot so you're not straining yourself. But, being that the wheels are so small, after a while, you feel your legs get swore. I guess the size of the wheel
On the other hand, the battery doesn’t lock into the bike, which means you can’t just leave it on your bike when you park at the bike rack. Anyone could walk by and simply remove your battery. That seems like an oversight to me, though perhaps the designers assumed that such a small battery would just be easy to take with you. And it is. My wife could probably lose this battery in her purse.