Folding bike wheel size: Traditionally, folders are small bicycles – but there are versions designed around full sized rims. Models with smaller wheels will be lighter and more compact when folded, but won’t gather as much momentum on the road. A folding bike with larger wheels will be much faster rolling once the wheels are up to speed – but will likely weigh more and will be little more cumbersome to load onto public transport.
Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed and angle measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally allow input by means of potentiometer or Hall Effect twist grip (or thumb-operated lever throttle), closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. Bikes with a pedal assist function typically have a disc on the crank shaft featuring a ring of magnets coupled with a Hall sensor giving rise to a series of pulses, the frequency of which is proportional to pedaling speed. The controller uses pulse width modulation to regulate the power to the motor. Sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy. An implementation is described in an application note for a 200 W, 24 V Brushless DC (BLDC) motor.
But as a commuter vehicle, the Metro just lacks a few crucial details. There are no eyelets to attach a rear or front rack, so your storage options are limited to racks that clamp onto the seat post, or baskets that attach to the handlebars. Both of these options have much lower weight limits than a traditional rear rack. Your options for fenders (a necessity for foul-weather commuters) are limited, too, since the wheel forks don't have very much clearance.
From their, you'll choose the motor size, and trust us, we’ve got plenty of motors to choose from. Whether you’re looking for a gentle 250w motor, a 500-750w motor to do some heavy cruising, or you're looking for a 1000w+ speed machine, we’ve got the ebike you want in your life. See why thousands of customers look to Bikeberry.com when shopping for an Electric Bike.