Radial-ply is the type of construction used by almost all modern tyres.

A radial-ply tyre has reinforcing 'plies' which run across the tyre - from the bead on one side, through the sidewall and tread, through the other sidewall to the other bead.

A radial-ply or radial tyre has a stiff tread area and flexible sidewalls, which improves grip, stability and refinement.