Steve, "Mr. NW Race Karts" let me run wild with his helmet.  He indicated that he loved the gears on my helmet and that he liked red and black.  

I went with an old school candy apple red on much of the helmet and incorporated a bunch of gears and 3D tiles on top.  Between the candy colors, the gears and the tiles up top, this helmet took forever but was worth the wait.

Custom Helmets

 For Racers, By Racers