Tubeless pneumatic tire with carcass having butyl-based inner topping rubber layer

A tubeless pneumatic tire comprising:

• a carcass comprising a plurality of carcass plies stacked one on the other, radially of the tire, each of said carcass plies having a carcass cord web and topping rubber layers unified with the carcass cord web on opposite sides thereof by calendering, said plurality of carcass plies including an outer carcass ply extending from the tread portion through the sidewall portion to the bead portion and turned up around the bead core outwardly from the inside of the tire in the axial direction and an innermost carcass ply extending from the tread portion through the sidewall portion to the bead portion and terminating at the bead portion without being turned up around the bead core;
• an inner liner formed of a butyl-based rubber and covering an interior surface of the innermost topping rubber layer;
• and
• a bead apex rubber provided in a portion surrounded by the turned up portion of the carcass and the bead core, wherein
• the topping rubber layer of the interior surface of the innermost carcass ply is formed of a butyl-based rubber,
• the topping rubber layers other than the topping rubber layer of the interior surface of the innermost carcass ply are formed of a diene-based rubber material, and
• difference Hc between radial distance Hb from the terminating end of the innermost carcass ply to a radially inside edge of the bead core and radial distance Ha from a radially outside edge of the bead apex rubber to the radially inside edge of the bead core is not less than 5 mm.