Abstract: There is disclosed carbon black for a tire tread which has a cetyltrimethylammonium bromide specific surface area (CTAB) of 120 to 160 M.sup.2 /g, a dibutly phthalate absorption number of compressed sample (24M4DBP) of at least 100 to 145 ml/100g, a tinting strength (Tint) of 100 to 150%, and such a value Ma defined by the following equation (1) as to satisfy the relationship expressed by the following formula (2): ##EQU1## wherein N.sub.2 SA is a nitrogen adsorption specific surface area (m.sup.2 /g), and Dst is the equivalent Stokes diameter (nm) at the maximum absorbance of the distribution curve of aggregates determined by the centrifugal classification method, and psMa.gtoreq.1.7-0.005 [CTAB]TM . . . (2).

Abstract: A rubber composition comprising 35 to 100 parts by weight of a carbon black per 100 parts by weight of a rubber component, the carbon black having a nitrogen adsorption specific surface area (N.sub.2 SA) within a range of 70 to 185 m.sup.2 /g and an aggregate characteristic which shows a first and a second modal diameters in the aggregate equivalent Stokes diameter distribution and has a difference between the two modal diameters L (nm) to be calculated from the following equation (1) which satisfies the following formula (2):L=Dst.sub.2 -Dst.sub.1 (1)20.ltoreq.L.ltoreq.110-0.3 (N.sub.2 SA) (2)wherein Dst.sub.1 and Dst.sub.2 respectively denote the first modal diameter (nm) and the second modal diameter (nm) in the aggregate equivalent Stokes diameter distribution detetermined by a centrifugal classification method.

Abstract: A carbon black for blending in rubber is disclosed, which has a BET specific surface area (N.sub.2 SA) within a range of 65 to 84 m.sup.2 /g, an a value to be obtained according to the following calculation formula, of at least 270 and a ratio of the BET specific surface area (N.sub.2 SA) to the iodine adsorption number (IA), N.sub.2 SA/AI, within a range of 1.10 to 1.35:a=(24M4DBP).sup.2 .times.(Blackness/IA ).sup.2 .times.(Dst).sup.2 .times.10.sup.