Tire fitment and suggestions for an air ride 68 Firebird

[firebirdzig]

Hey Guys, I've installed the level 2 air ride from ride tech on my 68 Firebird. The fenders were already rolled by the owner before me and I left them that way. I have 18 inch Forgeline wheels that i'm going to be running. I'm looking at a 245/18 in the front and a 275/18 in the rear. I'm looking to see if anyone has any suggestions on the tire size including the aspect ratio. Also what brand and style tire are people running on a car that will be used mostly for driving to work and trips up the hill to Tahoe? Not going to be using this for racing or much pro-touring but mostly cruising. Thanks in advance.