Rubber composition

A rubber composition comprising:

• a first synthetic rubber;
• a second synthetic rubber:
• and
• a filler,
• wherein a solubility parameter difference between the first synthetic rubber and the second synthetic rubber is greater than 0.8 and less than or equal to 1.1,
• the first synthetic rubber is a solution-polymerized modified conjugated diene-based rubber which has a styrene bond content of 38 wt % or more, and 55 wt % or less, and has a first functional group bonded to at both terminals, and
• the second synthetic rubber is a lithium-catalyzed modified butadiene-based rubber in which a second functional group is bonded to at least one terminal.