Pneumatic safety tire

A pneumatic safety tire comprising:

• a pair of bead portions with a bead core;
• sidewall portions extending radially outward one from each of said bead portions;
• a tread portion extending between the sidewall portions, said portions disposed outward of the carcass;
• a toroidal carcass extending through the tread and sidewall portions and turned up at the both edges around the bead cores;
• a belt disposed between the carcass and the tread and having cords laid at a relatively small angle relative to the equator of the tire;
• and
• a sidewall reinforcing layer disposed inward of the carcass in each sidewall portion,
• each sidewall portion provided with a minimum thickness at a position (E) between an outer edge point (A) and a 65% height point (B) both located on each side of the tire equator,
• the thickness of each sidewall gradually increased from the minimum thickness position (E) toward the 65% height point (B), wherein
• the outer edge points (A) are defined as the axially outer edges of a ground contacting region on the tread surface in a standard loaded state in which the tire mounted on a normal rim and inflated to a normal pressure is loaded with a regular load, and
• the 65% height points (B) are defined as the positions at 65% height of the tire section height (H) from the bead base in a standard unloaded state in which the tire mounted on the regular rim and inflated to said normal pressure is maintained free of load,
• the difference between the thickness (TB) at the 65% height point and the minimum thickness (TE) being in the range of 2.0 to 5.0 mm,
• each sidewall portion gradually increasing in thickness from the 65% height point (B) toward the maximum width position (C) where the axial section width of the tire is maximum in the standard unloaded state,
• each sidewall portion gradually increasing in thickness from the maximum width position (C) toward a contact position (D) where the bead portion contacts with a flange of the rim,
• the thickness (TD) at the contact position (D) being larger than the thickness (TC) at the maximum width position (C),
• the difference between the thickness (TD) at the contacting position (D) and the thickness (TC) at the maximum width position (C) being in the range of 2.0 to 5.0 mm
• the sidewall reinforcing layer is a cresent-shaped three-layered structure in which a hard rubber strip having a Shore A hardness of 70 to 90 and a 100% modulus of 30 to 70 kgf/cm.sup.2 is sandwiched between soft rubber strips each having a Shore A hardness of 50 to 70 and a 100% modulus of 10 to 30 kgf/cm.sup.2.