Wheel mod to use Ninjaflex tires on Greg Zumwalt's fantastic [Dual Mode Windup Car](https://www.youmagine.com/designs/dual-mode-windup-car). Tire tread was cannibalized from Palmiga's [Low Profile Rain Tires for OpenR/C](http://www.thingiverse.com/thing:1818514). I also uploaded a fix for the "axle spring" piece, because I discovered that the hex-shaped section of that axle is actually larger than the holes it's supposed to fit into. Rather than sanding the heck out of the piece, I decided to modify the STL and reprint it.