You're wrong, and even if you were right that wouldn't argue against GP's observ...

You're wrong, and even if you were right that wouldn't argue against GP's observation.

V_cm: velocity of center of mass

V_l: velocity at left edge

V_r: velocity at right edge

R: radius of stone

w: angular speed of stone (CCW is +)

  V_l = V_cm + R*w
  V_r = V_cm - R*w
  delta = 2*R*w

Even if it was dependent on linear speed / rotational speed, the only way to change # of turns / run is to change linear speed / rotational speed.