Toy Car with Captive Wheels

Toy car with wheels that move, but requires no assembly. Here is a short video:

http://www.youtube.com/watch?v=eWW5DFWcvhE

The wheels took some effort to loosen up after printing, but they now roll quite nicely on the right surface.

Other problems:

There is definitely some warping from the plastic cooling/shrinking (I used ABS).

The transition from the wheel to the axle is a bit steep for the makerbot.