Self-Sealing Tire Comprising An Additional Sidewall Reinforcement

A tire in the form of a torus having an internal wall and an external wall, the internal wall being, at least in part, covered with an airtight layer, the tire having an axis of rotation and comprising:

• two beads intended to come into contact with a mounting rim, each bead comprising at least one annular reinforcing structure having a radially innermost point;
• two sidewalls extending the beads radially outwards, the two sidewalls coming together in a crown comprising a crown reinforcement, radially surmounted by a tread;
• a radial carcass reinforcement composed of thread reinforcing elements having an elongation at break EBC and a breaking strength BSC, placed at a placement pitch PC and coated with rubber composition, the carcass reinforcement extending from one bead to the other, passing through the crown, the carcass reinforcement being anchored in each bead by a turn-up around the said at least one annular reinforcing structure, so as to form an outward strand and a return strand, the carcass reinforcement being designed so as to satisfy the inequality:
• BS
• C
• P
• C
• ≤
• 1.5
• ·
• 10
• 6
• ·
• (
• R
• S
• 2
• -
• R
• E
• 2
• )
• R
• T
• ,
• where BSC is expressed in newtons, RS is the radial distance between the axis of rotation of the tire and the radially outermost point of the carcass reinforcement, RE is the radial distance between the axis of rotation of the tire and the axial position where the tire reaches its maximum axial width, and RT is the radial distance between the axis of rotation of the tire and the radially innermost point of the said at least one annular reinforcing structure, the placement pitch PC and the radial distances RS, RE and RT being expressed in metres;
• each sidewall of the tire additionally comprising an additional strengthening reinforcement composed of thread reinforcing elements having an elongation at break EBA and a breaking strength BSA, placed at a placement pitch PA and coated with a rubber composition, the additional strengthening reinforcement extending between a radially internal end occurring close to said at least one annular reinforcing structure of the bead which extends the sidewall and a radially external end located radially between the carcass reinforcement and the crown reinforcement,
• in which EBA, BSA, PA, EBC, BSC and PC are chosen such that
• BS
• A
• P
• A
• ≥
• 1.3
• ·
• BS
• C
• P
• C
• ,
• 
• and
• EB
• C
• ≥
• EB
• A
• ,
• it being specified that the breaking strengths BSA and BSC and the elongations at break EBC and EBA are the corresponding values of the reinforcing elements before their incorporation in the tire,
• said airtight layer being, at least in part, covered with a layer of self-sealing product.