Tire size for a 18 X 9" rim and 18 X 8" rim

[old66tiger]

Looking at a 18X9 rear and a 18X8 front (maybe 18X7). Looks like a 25540R18 for the rear and either a 22545R18 or a 23545R18 for the front. Thoughts?

[b-man]

275/40-18 or 285/35-18 rear.

245/40-18 front.

I'm running 245/40-18s and 275/40-18s on 9" wheels front and rear on the Tempest.

[old66tiger]

How much space do you have between the wheel wheels and the tires? I have measured my wheel wells and with 275's I might have 1/4 to 3/8" clearance

[b-man]

I have about 1/2" on either side of the rear tire.

No mods to the inner wheelwells, no cutting or rolling of the fenders.

[old66tiger]

The area that I have the greatest concern is the rear inner part of the wheel tub. There is quire the arc to it that makes it tight. Maybe this area is different on the 64 verses the 66?

[b-man]

Probably not much difference between the '64 -'65 and '66 -'67 wheelwells.

If anything most would consider the wheelwells to be a little tighter on the earlier cars.

You are correct, that area at the bottom rear is the tightest. On my '64 GTO I did a little hammering so my 10X28 Goodyear slicks wouldn't rub in that area, they were mounted on a 15X8.5" wheel. The pic below is the driver's side from inside the trunk, you can see where the seam between the wheelhouse and trunk floor has been pinched from the hammering.



The 275-40-18s are quite a bit shorter at 26.6" so they fit a little better, plus they dont have that sharp corner where the tread ends like a slick does.

[Nine Ball]

I recommend 245 wide tires for 8" wide wheels, 275 wide tires for a 9" wide wheel.