Blue, white, red
Gray is The King's hauler.
Gray always knew that because of his size he'd be hauling cargo across country; gas, lumber, maybe even steel like his dad, but he never dreamt that the cargo would be seven time Piston Cup Champion, "The King" Strip Weathers.
Gray is also a friend of Mack. In The World of Cars #1, it is revealed that Mack and Gray go way back; their fathers had known each other.