Types of tire constructions:

Radial tire has a ply that is at or near 90 degrees to the direction of travel and the ply goes from bead to bead. Bias ply tire has the ply(s) cut at an angle and the plies are laid over each other in a criss cross method

Bias belt tire has a ply cut at an angle and the belt is wrapped around the circumference of the tire over the bias ply or radial ply

Zero degree belt is laid at 90 degrees to the direction of travel over the other plies

Benefit of a radial tire (if your bike can work with a radial construction tire) is :
1) a better, more compliant contact patch
2) better transitioning response over bias
3) not as forgiving as the taller profile bias
4) Low aspect ratio - better grip but at max adhesion they slide more quickly with less warning
5) low profile looks great on many bikes

Criteria for running radials
1) Suspension of bike must be stiff enough to work with radial tires
2) wheel width must be wide enough to work properly for radial application
3) never run a radial front and bias rear

--Sukoshi Fahey (Ms.)
Sales Manager, North America