Abstract: A pneumatic tire having a tread portion with a tread pattern which is constituted by main grooves, auxiliary grooves, lug grooves and sipes, wherein the mean depth Gc of the auxiliary grooves, the mean depth Gs of the lug grooves and the mean depth Gk of the sipes are determined in relation to the mean depth G of the main grooves so as to meet the following conditions:Gk/G=0.65 to 0.85Gc/G=0.7 to 0.8Gs/G=0.8 to 1.

Abstract: A pneumatic tire having on its tread surface a tread pattern formed by grooves and having a tread rubber of a two-layer structure comprising a cap rubber layer and a base rubber layer of which the latter comprises a rubber having a lower heat generating characteristic in comparison to a rubber forming the former, the tire being characterized by having a value within the range of from 0.15 to 0.35 for (Gc/G).times.(Eb/Ec), in which G is the total thickness of the tread rubber at the bottom of grooves in the tread pattern, Gc being the thickness of the cap rubber at the bottom of the tread pattern groove, Eb being the modulus at 25% elongation of the base rubber layer, Ec being the comparable modulus of the rubber of the cap rubber layer.