Spencer electric commuter bicycle does Oxford to London

Spencer is the men's commuter electric bicycle combining the lastest e-bike technology with classic city styling. Fitted with a maintenance free Panasonic motor that powers every turn of the pedal, and with three levels of assistance, you can choose exactly how hard you want the bicycle to work. The standard battery will give you up to 50 miles of assistance before it needs recharging or swapping - enough for the longest commute or leisure ride.

Even without the benefit of an electric motor, a bicycle's performance, in both biological and mechanical terms, is extraordinarily efficient. In terms of the amount of energy a person must expend to travel a given distance, investigators have calculated it to be the most efficient self-powered means of transportation. From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels.