A picture of the very incomplete gantry as it currently is, to give a better idea of what I'm up to: < > The only other way to get wheels to turn is either roll them freely unbound to anything, or attach them to a rotor. You can adjust the suspension settings to make them ridged, and you can use vertically oriented suspensions to prevent side wobble as if it was on rails. Wheels lack any form of propulsion on their own. They also lack any form of innate rotation ability. They're just cylindrical objects, exactly as they are in the real world (try welding a wheel directly to something sometime and see how well it spins). You need to provide an axle to them, and propulsion should you require it as well.
“Why would you want to lower it?” an unnamed Audi product planner asked when I’d shared my plans for the e-tron with him. “It’ll look like an Avant.”

@Michael Lau Presumably yes, since part of your energy will go into moving the hub within the wheels. But since they're springs, you'll get most of that back, so it's probably close enough to a wash to not matter much. Especially on a purely A-to-B type bike like a folder. Edison Ong April 18, 2013 06:40 AM
My background in wheel performance is its circular motion( which involves the circular of the wheel, and that the hub remains in the center of the wheel) if u are rolling with an oblong wheel, then u may actually exert more effort in lifting your self with the bike rather than rolling.