The present invention relates to a pneumatic tire, specifically to improvements
to the bead region of tires designed for runflat operations. The improvements comprise
the addition of cavities or indentation (126) on the surface of the bead
(127) that contacts the wheel rim (128). In a first embodiment a
series of circular cavities (126) are located on the radial innermost surface
of the bead in the proximity of the bead toe. In a second embodiment, a continuous
groove-like torus cavity (226) is located in the radially innermost surface
of the bead in the proximity of the bead toe. The series of cavities or torus cavity
increase the adherence of the bead to the rim as a small volume of air at a low
pressure, significantly inferior to the atmospheric pressure (air vacuum situation)
is trapped in the void spaces created by the cavities or torus cavity and the bead seat.