Originally Posted by
lucasgo
Cheap, practical way- install a hub motor kit (9C, Amped, whatever). If you want to go 25 without pedaling, use a 48v10ah battery. My 36v15ah holds me at 21-22 without pedaling on flats. I pedal it up to 24-25 without a lot of effort. 7 miles of riding feels like about 3. Most kits like this are not pedal-assist (meaning you have to pedal if you want to move) but have a throttle that you engage (thumb, half-twist, full-twist) to the degree you want. My thumb throttle makes a slight angle to the grip shift so it kind of gets stuck when fully engaged. I know it's not the safest, but I like the cruise-control nature it affords, especially in the very cold mornings.
There are some good hub motor kits out there, including Amped. However, if you decide to convert and existing bike with a hub motor kit you need to make sure that you do not use a front hub motor on a bike with an aluminum or suspension fork. Their drop outs are cast and subject to failure (due to torque) without warning, resulting in loss of control and possible injury; torque arms won't protect you. Here's a photo of a failed aluminum fork that had torque arms installed. Fortunately, the rider wasn't thrown into traffic and sustained only minor injuries. He posted this photo on his blog.
Even steel drop outs can fail over time due to torque but they're stronger than aluminum. Rear hub motors are safer (although there are some who argue that no hub motor is safe). With any hub motor, front or rear, it's critical that you use torque arms.
FYI--If you're in NY, you should be aware that there currently is a total ban on riding electric bikes in the streets. Some here have said that NYC police were turning a blind eye to enforcement. However, someone posted on the Endless Sphere forums that they were stopped on the streets in NYC last weekend and their bike and Ping battery were almost confiscated. So I don't know if the situation is starting to shift in NYC. There currently are 2 bills in the NY Legislature that would lift the ban (at least in part), the bill in the Assembly has passed but the one in the Senate has stalled. The bills differ and the Senate bill would only lift the ban on e-bikes that travel under 20 MPH. The Senate bill also mandates the use of helmets for e-bike riders and prohibits anyone under 16 from operating an e-bike.