The Morrison Roller Motion Shoe is built with a wedge profile and a progressively rolled toe. It has three distinct bottom surfaces that work as the horse moves (in this case from right to left):
A) Machined landing area extends ¾ inch on the ground surface at the heel relieved by 1 mm.
B) Weight bearing section in the center of the ground surface.
C) Progressively rolled toe.
The Roller Motion shoes are available in sizes 4 – 10 and all are wedged. The design has all the shoes machined from 5/8 inch thick aluminum plate – the max thickness at the heel. The primary variable in the design is the length of the shoes. This means that the wedge angle decreases as the length of the shoe (larger size) increases.
For those of you who have just said “What? …..Aren’t the wedge angles on this shoe fixed?” Trigonometry! This chart contains the measured dimensions of the machined aluminum alloy Morrison Roller Motion horseshoe with the math completed and the calculated angles shown. Remember….to get a usable hypotenuse you have to extend the angled hoof surface of the shoe until it touches the “ground”. The applicable formulas:
Sine = O/H [opposite divided by hypotenuse] + Angle (degrees) = Sine x (180/Pi)
NOTE: The Sound Horse Series I Morrison Roller Motion Shoe uses a flat, aluminum “thin plate” to allow ease of cold-shaping but maintains the same ground surface contours. The required wedge dimension is accomplished with additional urethane formed into the rim pad through the heel of the cuffed Series I horseshoe.