A DIY owner-built electric bicycle

Electric assist kits for bicycles are widely available around the globe. The Simple Cycle Project is not affiliated with any manufacturer and we make no brand recommendations.

Virtually any type and make of hub motor kit can be installed on a Simple cycle, regardless of axle diameter, axle length, torque-arm attachment details, and type of multispeed freewheel or cassette attachment.

Motors which bolt onto the frame and drive the wheel through an additional chain can also be utilized.

Battery, controller and throttle are easily mounted on a Simple frame.

Hub motors are built into a bicycle wheel, the motor body replacing the normal wheel hub. Both type of hubs will have bearings and mounting threads/holes for drive sprockets and (perhaps) disk brakes. 

In our experience, hub motors have been frequently problematic to fit on conventional metal-framed bicycles, and especially on composite frames. Any mismatch in specifications can result in the inability to utilize an already purchased motor on an already built frame. This is not a problem with Simple cycles.

Wheels that have "Rear" hubs can be used on any Simple cycle that utilizes rear wheels of that same size, regardless of axle diameter and length, which are easily made to fit on the wooden frame. "Front hub" motors can be mounted on any Simple model with the appropriate size of front wheel.  A throttle-controlled "Rear" hub (if that is all you have) can also be used on the front of a Simple cycle, requiring only a small change to the spacing of the forks.

Mid-drive motors attach to the crankset and add their power at the same point in the transmission that the rider does. Once installed, the mid-drive works in tandem with the person pedaling. 

Unlike a hub motor, the mid-drive motor "sees" any rear wheel sprockets, so creates a transmission that has the ability to shift gears. When the rider of a mid-drive system shifts to a higher or lower gear for themselves, they are also shifting for the motor. This results in both higher cruising speeds and stronger climbing torque than that provided by a single-speed hub motor of the same rated power.

Most Simple chain-drive bikes have room at the crankset for attachment of a mid-drive. You may need to shave some wood if the fit is tight.

Motors from other applications (household appliances, fans, etc.) have been modified by inventive persons and attached to all kinds of tricycles and pedicabs. This same approach can be taken with Simple trikes, as well. The attachment of the motor is made easier by giving you the option to include the Simple trike's jackshaft in the motorized transmission. The jackshaft allows you to put the motor and the sprocket it is driving in a number of different locations on the cycle, and in an optimal gear ratio. 

We do not at this time have any instructions for modifying motors in this way.