You can print it on a single plate and make the tires black by printing the first 3 millimeters in black and the rest in your desired color.

Insert the longer part of the wheels through the opening under the car and press the second part of the wheels firmly on the other side.

No supports are required for 3D printing.

You can insert the balloon over the designated opening and inflate it by blowing through the small hole where the air usually escapes. This way, you don’t have to take out the balloon every time.