Pneumatic tire

A pneumatic tire comprising:

• a tread portion having a tire equator and axially outer tread edges, the tread portion being provided with:
• a pair of circumferentially and continuously extending crown main grooves disposed axially both sides of the tire equator;
• a pair of circumferentially and continuously extending shoulder main grooves disposed axially outside of the crown main grooves;
• a pair of middle portions each of which is between the crown main groove and the shoulder main groove;
• and
• a pair of shoulder portions each of which is disposed axially outward of each shoulder main groove,
• the tread portion having a contact surface being covered with a cap rubber layer which is made of rubber having a loss tangent in a range of from 0.03 to 0.18,
• the middle portions being provided with only a plurality of middle lug grooves having groove widths in a range of not more than 2 mm, each middle lug groove extending from one end connected to either the crown main groove or the shoulder main groove to the other end terminating within the middle portion,
• the middle lug grooves having an angle in a range of from 40 to 55 degrees with respect to a circumferential direction of the tire, the middle lug grooves comprising first middle lug grooves having said one end connected to the crown main groove with the first middle lug grooves comprising an axially inner groove portion having a constant groove width W9 and an axially outer groove portion having a constant groove width W10 that is smaller than the groove width W9, wherein a ratio W10/W9 of the groove width W10 to the groove width W9 is in a range of from 0.50 to 0.70, and wherein the axially inner groove portion extends at an angle larger than that of the axially outer groove portion with respect to the circumferential direction of the tire, and
• each shoulder portion being provided with a plurality of first shoulder lateral grooves having axially inner ends connected to the shoulder main groove, having axially outer ends terminating within the shoulder portion without reaching the tread edge, and having groove widths in a range of not more than 2 mm.