the wheel effect has to do with the "scanning" frequenz of our eyes/brain =~ 24frames a second

if the wheel turns exactly the angle of one spoke in one frame our eye cant recognize if its turning forward or backwards. similar to what happens if you post 2 screenshots next to each other where one wheel has turned just the ammount of one or a multiple of the spoke angle. (the wheels match on each other so does our brain "see" it as well)

if now the wheel turns just a little bit less then the distance of the single spokes it seams to turn backwards.

this would work with a flip-book as well or your monitor: imagine a point at the very right of the screen. Now with every frame the point moves 100% of the direction. the result would be nothing - a still standing point.
if the point now only moves 99% of this direction per frame, it will start to move slowly from the right side to the left one till it appears on the origin again.

now its up to you to figure out what happens at 10% or even at 50%

phew, way to much text for something so unimportant like this
especially if you put some spin-wheels on your car

sreehc