Pneumatic tire with tread having crown rib and middle ribs

A pneumatic tire comprises circumferentially-continuously-extending crown main grooves and shoulder main grooves to divide the tread portion into one crown rib, two middle ribs and two shoulder ribs. The middle rib is provided with a circumferentially-continuously-extending middle sub groove to define an axially inner part and an axially outer part. The axially inner part is provided with inner middle lug grooves comprising an axially outer wide main part and an axially inner narrow part. The axially outer part is provided with outer middle lug grooves comprising an axially outer main part an axially inner sipe-like narrow part . The width and position of the middle sub groove, and the widths of the lug grooves are specifically defined in order to improve the wet performance and noise performance in a well balanced manner while maintaining the steering stability.