hey...budling a 69 vertable....gonna run 18's...its lowered with tube arms and multileaf outback. Anyways, What size backspacing should i use..and what WIDTH is suggested front and back..wanna go wide aspossible without to much folding or cutting of fenders

There is a real good article in this months Car Craft showing how to measure for max tire size.

One point made was that no two tires from different manufacturers are actually the same size. In other words...if you have 275/35/18's from two different manufacturers, one might rub where another will clear.

Also...depending on rim width, a tires track width will vary. For every 1/2" in rim width you gain or loose 0.2" in track width.

Tim

I know all about measuring for tire etc...I have a tire shop....but Im wondering what rims will fit these cars...for section width

You said the car is lowered and you don't want to do too much hammering but you want to go as big as possible so here goes.
Front 18x8 - backspace 4.75 to 5.0 with a 245/40-18 tire or an 18x8.5 with a 5.25 backspace (+ or - an 1/8") same tire.
In the rear 18x9.5 - backspace 5.5 with a 275/40-18 tire.
If the car is square - meaning both sides are equeal these should fit with no pounding. The rear will be tight and may rub a little on the inside over a curb cut. You said you have a tire shop so just make sure you measure both sides because one side could be a little different than the other. Good luck.

perfect...thanks very much

on the rear, you should have 12" from the inside wheel well to the inside fender lip. there will be upto 1/4-1/2" difference on the right rear. I just order 17x9.5 for the rear with 275/40/17 Firestone wideovals. I came up with 5.5" back spacing. American racing said the TTII is actually about 10" wide and that the 5.5 would be about perfect. As for the front I will be running 17x8 with 4.75" backspacing and using a 245/45/17. I am going to use 2" drop springs in the front and try 2" in the rear, but may have to go with 1.5". I am hoping that the rims will be in in the next couple of days. They (American Racing) said it can take upto 6-8 weeks!!! The TTII's i order are the one with the grey center(205) I think it will look slick on a black car.