Runflat tire with tread stiffening member

A pneumatic runflat tire having a radially outer tread, a belt reinforcing structure radially inward of the tread, the belt reinforcing structure having at least two cord reinforced layers, and a carcass reinforcing structure including at least one cord reinforced ply extending to a pair of annular bead cores, the tire when mounted on a design rim and normally inflated but unloaded has a section height H and a section width W, wherein W is greater than H, the tire having H being greater than 4 inches (10 cm) and the ratio of H/W defines the aspect ratio of the tire, the aspect ratio being greater than 50%;

• a pair of sidewalls extending from the tread radially inward toward the bead cores, each sidewall having two runflat elastomeric inserts, at least one elastomeric insert radially inward the at least one carcass ply, the inserts having a maximum thickness of 8 mm and 7 mm, respectively, a tread stiffening member in combination with the sidewalls, tread and the other underlying composite reinforcements, exhibiting a deflection profile of the tire, wherein the normally inflated 30 psi deflection D30 of the tire under normal load is less than 20 mm and the 0 psi deflection D0 under normal load is less than 40 mm and the difference between the normally loaded and inflated deflection D30 and the D0 deflection is substantially equal to or less than the amount of deflection D30.