I need to know how to attach a wheel to an axel, but first of all, i need an axel with a gear pre-built into it. The axel needs to be over 20 inches long (because that is the width of my vehicle) and support bicycle/tricycle wheels. Does anyone know of such wheels and axels? (The wheels have to be thin). ___________________________ My second problem is choosing a motor for my vehicle. The motor will be pneumatic and run off of a tank with a capacity of probably a little over 7127 inches cubed at ~100-110 psi. I want to get a motor from here: http://psiautomation.com/model_specs.cfm?horsepower=0.75&model=DVA-003 But my main concern is the air consumption rating of 45 scfm. And my big question is how something that takes in 90psi can generate 3/4 horsepower. How does that happen? Finally, if i cant supply enough air to the motor using a tank, could probably just put an electric generator in with the air inflator to make it move.