Can you make 2 inches appear?

[zerfetzen]

Can you make 2 inches appear?

Ok, on my prior 73 Cuda, everything I saw on this board about tire/wheel sizes applied perfectly.  I had Cragar rims with 3 1/2" backspacing and Hoosier tires that were 275/50/15's.  The outer tire could rub the quarter panel with a good bump, so I had air shocks to keep it up to be safe.  Future plans were to replace with Edelbrock or Koni shocks, and replace the wheels with Wheel Vintique Rallye wheels from JEGS, with I think 4 1/2" backspacing, which should bring the tires in toward the leafsprings an inch.  So I measured and had 2 inches.  All good to go.

Then that Cuda got rear-ended and I just got a 74 Barracuda.  This one has the same issue: it already has the exact same white monroe air shocks, and has 275/60/15's on Centerline AutoDrag rims.  I'm not sure what the backspacing is, and wonder how to measure that?

Regardless what it is, the tire is about 1/8 inch from the leaf springs.  How is this possible?  The same width tire and 2 inches disappeared.  The outside still can rub with a bump, and the inside is too close to the leaf springs for my comfort.  How is this possible?

Can you make 2 inches appear?

[HemiDog]

To measure the backspacing on the wheel, lay something straight across the diameter of the wheel lip on the back side of the wheel.  Make sure you do not have what ever that is on the tire though.  Then you can measure the distance from there to the mounting surface of the wheel.  That should give you what the backspace is for that wheel.

The width of the rim will also change the width of the tire, so since you are talking about the same size tire, check the rim widths.

Did your 73' have the spring relocation kit?

[Bullitt-]

what if the wheel was 2" wider with 2 more inches of backspace. 

[ShelbyDogg]

Did you try the old wheels and tires on the new car yet?

[zerfetzen]

Getting the Hoosier's off the other car may be more trouble than it's worth, and the 73 did not have its springs relocated, but HemiDog hit it right on the head, why didn't I think of that?

Width of BFG Comp TA's on 74 Bar.: 12 1/4"
Width of Hoosier's on 73 Cuda: 10 7/8"

That's 1 3/8", plus the backspacing must be a little different.  I guess I just assumed that 275mm width = 275mm width.  I'm betting that instead of my 73's 15x8 rims, the 74 has 15x8.5's.  Man that makes a lot of difference!

[EVIL72]

 The backspacing is probably 4 7/8 I have the exact same 15 x 8.5 Centerlines on my Challenger.
Centerline didn't give alot of options in backspacing for the autodrags  it was either 3-5/16ths or 4-7/8ths for the 15x8.5