Pedal powered air compressor - petebachant/petebachant.github.io GitHub Wiki

Typical volume of a car tire is about 0.01 cubic meters (need calc/ref). At 35 psi, this is 24 kJ of energy to fill with no losses. A cyclist can provide about 200 W, which implies a car tire could be filled in about 12 seconds, or 15 with an 80% compressor efficiency. This seems pretty low. However, a typical small consumer-grade air compressor has a 0.3 hp (220 W) motor, so this may not be all that out of the question.

Of course others have done this: http://www.instructables.com/id/pedal-powered-air-compressor/. This guy claims it takes 15 minutes to fill a 30 gallon tank to 50 psi, so that's about 40 W reaching the tank.

Would be nice to set it up like a turbo trainer, such that a normal bike could fit right in. Also, it would be nice to be able to use an electric motor as well.