I challenged myself over Christmas break to come up with a two axle chassis with spinning wheels that can be printed without support and without post assembly.
I also wanted it to have a bounce to the suspension. After about 8 iterations this is what I came up with. I designed a car and a truck to sit on the chassis.
I tried to make it so that the chassis took 3 hours to print and the car took 3 hours to print. The truck top takes about 4 hours because it is slightly larger.
This was printed on my Maker Select V2, with an all metal hotend.
The smaller the resolution, the more lines in the hood due to the slight angle.
The chassis doesn't need a brim or support but is less stringy with supports and it only adds about 30min.
The car top and truck top need supports. (touching build plate). They were designed to be printed with the top facing up. The Car file needs to be flipped around.
The tops clip onto the chassis with a snap fit design, so no glue or post processing is necessary.
For the green car and truck in the image, I printed out the part in grey and coated in XTC-3D from smooth-on. It self levels on the part (doesn't actually melt the plastic) making it smooth to the touch but you still see the ridges. I added a drop of green oil paint to the epoxy giving the translucent color seen in the image. It took about 2 hours to dry to the touch.