Heavy-duty pneumatic tire

A heavy-duty pneumatic tire comprising:

• a section width being equal to or less than 335 mm;
• an aspect ratio being equal to or less than 55%;
• a toroidal carcass extending between axially spaced bead portions through a tread portion and sidewall portions, wherein the carcass comprises a carcass ply comprising a main portion extending between bead cores each disposed in a respective one of the bead portions through the tread portion and the sidewall portions, and a turn-up portion turned up around each bead core of each bead portion from axially inside of the tire to outside of the tire and extending to a radially outer end thereof, and wherein the carcass ply comprises steel cords having a cord diameter of from 0.6 to 0.8 mm, and the steel cords are arranged so as to have 20 to 30 ends per 50 mm width of the carcass ply;
• a belt layer disposed radially outward of the carcass in the tread portion, wherein the radially outer end of the turn-up portion is located between the main portion and the belt layer in the tread portion;
• a cushion rubber disposed between the main portion of the carcass ply and each edge of the belt layer, the cushion rubber extending to a radially inner end thereof located radially inwardly of the radially outer end of the turn-up portion of each bead portion;
• a sheeted rubber layer disposed between the main portion and the turn-up portion in each sidewall portion;
• a tapered bead apex rubber being disposed in each bead portion, the bead apex rubber extending radially outwardly from the bead core to a radially outer end thereof between the main portion and the turn-up portion;
• a tread rubber disposed radially outwardly of the belt layer to form a radially outer profile of the tread portion;
• a chafer rubber defining an outer bead profile of each of the bead portions, the chafer rubber having complex modulus of from 10 to 15 MPa;
• and
• a sidewall rubber defining an outer sidewall profile of each sidewall portion and having complex modulus E*4 of from 3.0 to 5.5 MPa, the sidewall rubber having a radially innermost end and a radially outermost end,
• wherein:
• in each bead portion, the radially outer end of the bead apex rubber is located radially outwardly of a straight line that is perpendicular to the main portion of the carcass ply and passes the radially inner end of the sidewall rubber,
• the sidewall rubber comprises a first portion extending radially inwardly from the radially outermost end of the sidewall rubber, a second portion extending radially outwardly from the radially innermost end of the sidewall rubber, and third and fourth portions extending between the first and second portions,
• the first portion has an axially inner surface that directly contacts with the tread rubber,
• the second portion has an axially inner surface that directly contacts with the chafer rubber,
• the third portion has an axially inner surface that directly contacts with the cushion rubber,
• the fourth portion has an axially inner surface that directly contacts with the turn-up portion of the carcass ply, and
• a radial length of the fourth portion is smaller than radial lengths of the first portion and the second portion.