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Discussion Starter · #1 ·
I'm looking at putting the 17 x 9 steelies wheel vintiques makes on my 68 fastback. Wheels have a 4.5" back space. I was originally thinking 245/45 or 255/45 but then started thinking more and a 275/40 is the same height as a 245/45 and still falls in the 9 inch wide wheel width recommendation. Anyone know if the 275/40 will fit on the rear using the specified wheel width and backspace? Will it work on the front? I've got an old 245/45 tire laying around that I'm going to try using for a little measuring to see what I think but anything I can get from someone with experience would definitely be appreciated. Even someone saying they are running 255's and what clearance they do or do not have left is helpful.
 

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if the 245x45's fit with no issues i would bet at least 265x40's would have no problems. i've found going to a lower series lets you increase the width due to less bulge on the sidewalls. with 4.5" backspacing do you have any clearance problem with rear springs?
I have a 69 ranchero, i would think it is the same specs as your 68 fairlane and im interested in your outcome.
 

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Discussion Starter · #4 ·
There are 6 1/4" from the leafs to the wheel mounting surface on the rear. There are 5.5" from the mounting surface to the "virgin" lip of the wheel well on the unrolled quarter panel. So, the 9 inch wheel with 4.5 back space isn't a problem although a little more backspace would probably be ideal. I'm going to go with those wheels and a 275 tire I think on the back. I shouldn't even have to cut the lip at all as the tire I'm looking at is a 10.9 section width measured on a 9.5 inch wheel. I might to something there anyway just for added clearance.

I had a 245/45 laying around so using it to do some measuring on the front it looks tight on the upper control arm at the 4.5 backspace. If I were to run the 17 x 9 on the front it'd be close. An 18 x 9 with that backspace would actually be great as the extra rim diameter would push things out past the control arm. So on the front I'm looking at either a 17 x 8 or a spacer on the 17 x 9.

I'll be sure to update when the tires and wheels are on for anyone else that might be interested.

_________________
1968 Ford Torino GT fastback - 289, auto, 2.79 rear
2004 Ford Lightning
Recently Sold - 1994 Thunderbird - DOHC 4.6L, 4.10's, big sway bars and lots of accompanying suspension mods.

<font size=-1>[ This Message was edited by: 4camtbird on 3/30/06 10:15am ]</font>
 

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An old thread indeed, but still relevant. My note is to be sure folks are aware that wheels are 1" wider than their listed size. So for example, a 17x9 wheel is physically 10" wide, and 9" across the tire bead seats. This is mostly important when combined with backspace. As the wheel is actually 10" wide, a zero offset would be 5" backspace - not 4.5". Just a reminder to throw that into your calculations.

One more tip. Any tire and wheel combo that will fit (whatever is on there now) can give you a basis for measuring clearances with larger wheels and tires. Simply draw-up your current wheel and the tire as listed in tire spec's, then measure your clearances to all nearest points at any suspension travel and turning for fronts. Use the closest points to determine clearance and give yourself a bit of wiggle room. Write these clearances on your drawing where you measured.

To choose your tires and wheels, look-up the specs for a tire that will fit in those clearances, with a bit of their own clearance. So for example, your current rear wheel and tire have exactly 3" clearance to anything inboard, and 2" to anything outboard. That's 5 inches of room. Let's say we want a minimum of 1/2" clearance on each side for safety (1" total). Your new tire can be 3 + 2 - 1 = 4 inches wider. Be sure to check clearance at any new height based on larger diameter as well. But, it won't fit unless you center the extra width, so your new wheel will have to sit 1/2" further inboard, meaning you need 1/2" more backspace to get it there.

Don't overlook custom offset wheels or DIY wheel shells and rims to get the max tire with perfect clearances.

David
 
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