| abstract |
The present invention provides a rubber composition that can enhance the fuel economy, wet-grip performance, abrasion resistance, and kneading processability in a balanced manner, and a pneumatic tire using this rubber composition. The present invention relates to a rubber composition that contains a rubber component and silica, wherein the rubber component contains, based on 100% by mass of the rubber component, 10 to 70% by mass of a high-cis polybutadiene having a cis content of 95% by mass or more and satisfying the following requirements (A) to (C): (A) a Mooney viscosity (ML) of 40 to 49; (B) a molecular weight distribution (weight-average molecular weight (Mw)/number-average molecular weight (Mn)) of 3.0 to 3.9; and (C) an index (n-value in Expression (1) below) of velocity dependence of Mooney viscosity of 2.3 to 3.0, and 30 to 90% by mass of a conjugated diene polymer containing a constituent unit based on a conjugated diene and a constituent unit represented by formula (I) below, and an amount of the silica is 5 to 150 parts by mass per 100 parts by mass of the rubber component,n nlog( ML )=log( K )+ n −1 ×log( RS ) (Expression 1)n nwherein RS indicates the number of revolutions per minute of a rotor, K indicates an arbitrary number, and ML indicates a Mooney viscosity, |