An automatic bicycle shifter making use of a global positioning system (GPS) altimeter for sensing road inclination, an accelerometer for sensing bicycle acceleration and a hot wire anemometer for sensing wind load, and through application of classical law of conservation of energy attenuates or appreciate automatic shifting speeds in real time to maintain a rider standard shifting torque. Automatic bicycle shifter is additionally provided with capability to sense, record, and interpret rider automatic shift override commands and further adjust automatic shift criteria to rider preference.