rear wheels

I'll check tonight.  I know close.  I think it was about an inch.

bcsideshow wrote: I run 275/50-15's.  They rub slighlty on big bumps.  my car is lowered though.  Depending on where you are ride height will affect this.  My wheels are 15x8 with 4.5" back space.

Do you have any rubbing problems with the front wheels? It looks kind of close.

'69 AMX
15x8 rim, 4-1/2" backspace, 255/60/15 tire = 1"+ to leaf spring
15x8 rim, 5-1/2" backspace, 255/60/15 tire = ~1/8" to leaf spring

imho a 5 inch backspace 15x8 rim would be "ideal" if available.
An 8" rim, 5" b.s., 255/60/15 should have 1/2"+ leaf spring clearance.
8" rim, 5" b.s., 275/50-60/15 should have 1/4"+ leaf spring clearance.

A 255 section width tire is 10" wide at the widest point on the sidewall
when mounted on an 8" rim.
Ideally specified rim width is 2" narrower than the tire section.
A 275 section tire is 10.82" wide at the widest point on the sidewall,
so would say they'd still be "ok" on an 8" rim, too narrow for 10" rim imho

I had "newer" Leaf Springs and "sometimes" on big bumps the rear 255/60/15 tires on 15x8 w/ 4-1/2" backspace WOULD RUB on the rear fender inner lip, but only right at the spot where the vertical "curl" of the body shape causes the rear wheel opening to "crossover" the corner of the rear tire at about the 2 & 10 o'clock positions.

Always feel compelled to say about rim size & backspace & etc dimensions & measurements,
"Stated" rim sizes are to the Bead Seat on the Rim, NOT the bare rim lip-to-lip overall measurements.
Generally, a bare Rim overall lip-to-lip physically measures 1 inch more that it's Stated Size.
But oddly imho, Backspace IS measured from the LIP to the Hub Mounting Surface.
So....
a Stated 15x8 Rim measures 16x9 overall lip-to-lip, so 4-1/2" backspace is 0" (zero) Offset.
a Stated 15x8 Rim measures 16x9 overall lip-to-lip, so 5-1/2" backspace is 1" inch Offset.
I always fail to remember which direction is called Positive Offset and/or Negative Offset.

Some additional possibly useful reference info:

1969 AMX Stock Wheels and Tires misc Info:

AMX Trim Rings are 2.5" wide

AMX Center Caps are 1-7/8 tall, 2-3/4 base dia & 2-1/4 top dia
    Center Cap Dish is 1/4 deep x 1-7/8 top & 1-3/4 btm dia

AMX Center Hub Bore Diameter INFO:           
>  AMC CTR Hub Hole Dia = 2.815/2.830 I.D measured old stock stl rim
> Mosr CTR Hub Axle Dia = 2.815 O.D measured Moser Axle
> Ford CTR Hub Hole Dia = 2.785 ???? per a forum post
> Weld Whl Hub Hole Dia = 3.180 inch ? PER WEB SPEC

Stock Tire Info:

Std = ~25" dia. = 6.95x14 w/ 14x5.5 Rims:

BIAS      BIAS & BELTED         NON METRIC       METRIC
PLY       BIAS PLY              RADIAL PLY       RADIAL PLY
6.95x14   C78-14                CR70-14 CR78-14  215/60-14 175/80-14
--------------                           O.D. =   24.16" ... 25.02"

Opt = ~26" dia. = E70-14 w/ 14x6 Rims:

BIAS      BIAS & BELTED         NON METRIC       METRIC
PLY       BIAS PLY              RADIAL PLY       RADIAL PLY
7.35-14   E60-14 E70-14 E78-14  ER70-14 DR78-14  255/60-14 215/70-14 185/80-14
--------------                           O.D. =   26.00" .. 25.90" .. 25.65"

Std - Tires
= E-78-14 (6.95x14) with Rims = 5.5 x 14 with ?.?? Backspacing

Opt - Tires
= E or F-70-14 with Rims = 6.0 x 14 with 4.00 Backspacing (measured mine)

6" rim measures 7 inches wide / 2 = 3.5 b.s. when there is 0.0 Offset
so stock 6" rims with 4" backspace have 1/2" Offset
so Hub to Hub is greater than Track Width by 2 times the 1/2 offset, or 1 inch

Hub to Hub, both front and rear, is 1.0 inch greater than
stock Track Width dimensions based on stock wheel offset.

1968-69 Track Width Dims from TSM:
59.38 inch = Front Hub to Hub = 58.38 Stock Front Track + 1.0 inch
58.00 inch = Rear  Hub to Hub = 57.00 Stock Rear  Track + 1.0 inch

1970 Track Width dims from AMA Data sheets:
60.30 inch = Front Hub to Hub = I6 59.30 Stock Front Track + 1.0 inch
60.70 inch = Front Hub to Hub = V8 59.70 Stock Front Track + 1.0 inch
58.00 inch = Rear  Hub to Hub = 57.00 Stock Rear  Track + 1.0 inch

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"Calculated" distance between sidewalls of 255/60/15 on 5-1/2 backspace.
255mm = 10.04 ÷ 2 = 5.02 + 1.0 offset = 6.02 Hub to Inner Sidewall
12.04 = 2 * 6.02 Hub to inner sidewall on each side
58.00 hub to hub - 12.04 = 45.96 = "calculated" between Sidewalls
..........  versus 46.00 = measured outside to outside of the Leaf Springs
........  reference 2.50 = Width of Leaf Springs

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