interesting idea from car air conditioner motor
How many psi could reach?
bikecompressor manual from car air conditioner
people debate this on question sites. people say its possible and can generate upwards of 100psi and even 200psi. and others reckon its not possible because ac compressors, compress Freon not air and the Freon is mixed with a lubricant. I guess that in a way it should work, like fridge compressors but those are in a sealed container of oil. if you have one lying around and a old bike try it, you will have to take of the clutch and replace it with a sprocket, find fittings for it a tank to compress. a welder be handy.