Imagine riding against the wind, uphill, towing a suitcase full of luggage, and not even breaking a sweat. That's the power of SRAM E-matic, our brand new electric assist hub. It's an utterly simple system, not cluttered by displays, a tangle of cables, or complicated hardware. The enclosed and protected rear-wheel hub includes a torque-sensor, controller, motor, and an automatic transmission system. The torque-sensor monitors the rider’s effort and the controller delivers proportional motor assistance as needed. The transmission shifts automatically to ensure that the rider is always in the “right” gear, delivering power at low speeds for getting started or getting up hills, and efficiency at high speeds.