Aerodynamics and your forks:

In order to improve airflow all leading edges
should be smooth and produce the correct
shape to allow air an easy passage over the
surfaces. This will minimise drag

Air separates from a circular cylinder and leaves a turbulent wake with a low-pressure region in the rear of the cylinder. The pressure difference between the front and back creates a high drag. Cd =1.2.

Shapes with sharp edges are much worse than cylinders. All edges should be rounded to avoid unnecessary drag. By putting a radius about 0.2 times the height on the corners of this box-shaped cylinder, the drag can be lowered from Cd = 2.0 to Cd = 1.3

Air flows smoothly around a streamlined airfoil without turbulence. A wing shape takes less than 1/10 the energy to move through the air than a cylinder and less than 1/20 that of a box shape.
The longer the airfoil is with respect to the thickness (chord-to-thickness ratio), the lower the drag. Cd = 0.1 or less.

 
When the rear of an airfoil is cut off, the drag increases because of the higher base drag due to turbulence at the rear. Cd = 0.3.

A two-to-one ellipse (width-to-height ratio) has a drag lower than that of a cylinder, but not as low as that of a cut-off airfoil section. Cd =0.6.

llustrations by kind permission of Human Kinetics, the Publishers of High-Tech Cycling by Edmund R. Burke, Phd.
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