Patent ID: 8210219

Claim:
A pneumatic tire comprising a tread portion provided with a pair of circumferentially-continuously-extending crown main grooves disposed on both sides of the tire equator, and a pair of circumferentially-continuously-extending shoulder main grooves disposed on the axially outside of said crown main groove, so that the tread portion is divided into ribs including a crown rib between the pair of crown main grooves, a pair of middle ribs between the crown main grooves and shoulder main grooves, and a pair of shoulder ribs between the shoulder main grooves and tread edges, wherein the middle rib is provided with a circumferentially-continuously-extending middle sub groove having a width of from 1.5 to 3.0 mm and having a groove center line positioned between 20% and 45% of the width of the middle rib from the axially inner edge of the middle rib, so as to define an inner middle part and an outer middle part, the inner middle part is provided with inner middle lug grooves which are arranged circumferentially of the tire at intervals and which extend from the middle sub groove toward the tire equator side and terminate without reaching to the crown main groove, said inner middle lug groove comprises an inner lug's main part having a groove width of not less than 1.5 mm and formed on the middle sub groove side, and an inner sipe-like part having a groove width of less than 1.5 mm and formed on the tire equator side of the inner lug's main part, the outer middle part is provided with outer middle lug grooves which are arranged circumferentially of the tire at intervals and which extend from the shoulder main groove towards the tire equator side and terminate without being connected to the middle sub groove, said outer middle lug groove comprises an outer lug's main part having a groove width of not less than 2.0 mm and formed on the shoulder main groove side, and an outer sipe-like part having a groove width of less than 2.0 mm and formed on the tire equator side of the outer lug's main part.