WHAT SIZE DRAG RADIAL SS SPRING '65 DART

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A/MP

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Come spring, an index class starts and car must use drag radial. At this point I am using a 7" slick on a 14" rallye wheel. Want to move up to a 15" wheel. How big of a drag radial can I fit w/o moving the springs and using mini tubs?
 
A/MP said:
Come spring, an index class starts and car must use drag radial. At this point I am using a 7" slick on a 14" rallye wheel. Want to move up to a 15" wheel. How big of a drag radial can I fit w/o moving the springs and using mini tubs?
Click to expand...
My '66 Barracuda will take a 235x60x15 on a 7" wheel pretty easily.
 
On that 235X60 radial, what's the backspacing? Thanks
 
I've seen guys get a 255 radial under an early A. It's close but it fits. Gotta get the backspace right. Probably not terribly helpful but I've seen it first hand.

My old '65 Valiant had 245/60/15s on a 15 x 8 wheel, 4.875" bs. They fit but rubbed sometimes if there were large enough people in the back.
 
I'm using P235/60-15 on 15x7" rims with 4 " backspace . Backspaces from 3 3/4 to 4 1/4" will work without problems . Sticky Mickey's S/S radials because I drive on the street . Going to run in 12.50 index and I need another 20 rwhp to get there .








g
oin
 
A/MP said:
Come spring, an index class starts and car must use drag radial. At this point I am using a 7" slick on a 14" rallye wheel. Want to move up to a 15" wheel. How big of a drag radial can I fit w/o moving the springs and using mini tubs?
Click to expand...
275 r 60 15's fit with no tubing but you have to move your spring perches, and measure measure measure,to get the correct back space on your wheels.
20150725_112605.jpg
 
Did 15x7 cop car steelies with mickey thompson 235-65's on my 66. barely a 1/4" from the inside side-wall to leaf spring. everywhere else was golden.
 
We're attempting a 15 x 8 with 4.5 back spacing with a 275/60/15 on a 1963 valiant.

Lips rolled and moving springs inward 1/2 - 3/4".

Fingers crossed. Lol
 
prorac1 said:
We're attempting a 15 x 8 with 4.5 back spacing with a 275/60/15 on a 1963 valiant.

Lips rolled and moving springs inward 1/2 - 3/4".

Fingers crossed. Lol
Click to expand...
Keep me in the loop with your results.
 
GREGG`PICTURES 001.jpg
I have been running M/T 255x60x15 on Weld Wheel 15x7/4.5 inch backspacing for 12 years or more with stock spring location and 1 inch lower caltrac mono leafs, with no tire rub at all even with 4 people in my 66 Dart
 
19DART66 said:
View attachment 1715140233 I have been running M/T 255x60x15 on Weld Wheel 15x7/4.5 inch backspacing for 12 years or more with stock spring location and 1 inch lower caltrac mono leafs, with no tire rub at all even with 4 people in my 66 Dart
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If I may ask.

How close is it to the spring?

And how close is it to the quarter?

We want to run a "regular" radial 275/60/15. And a standard 275 is almost the same dimensions as a 255 drag radial. But we're stuck between a 7" and 8" wide wheel. Both with 4.5 backspace.

Thanks. Eric
 
Last edited:
383Scampman said:
I'm using P235/60-15 on 15x7" rims with 4 " backspace . Backspaces from 3 3/4 to 4 1/4" will work without problems . Sticky Mickey's S/S radials because I drive on the street . Going to run in 12.50 index and I need another 20 rwhp to get there .








g
oin
Click to expand...

This is as big as i would go with stock dimensions. Bigger will fit but tires do not stay the same size during different temp changes let alone burnouts.
Buddy wih 255 60 15’s on a 66 dart got cute leaving a car show recently doing a burnout and both rear tires hit rear quarter inner lip and exploded.
Luckily no quarter panel damage just embarrassment.
 
Eric there are a lot of variables in tire and wheel fitment. On my Dart all of my measurements were taken after I made sure the stock A body 8 3/4 with stock 10" drum brakes was centered side to side then I took all my measurements to center the wheel and tire combo between the leaf spring and fender well ( my car has a dana 60 in it now that was narrowed to the exact width of the 8 3/4). If you add B body drum brakes or disc brakes your going to need more backspacing. When measuring the wheel to center the tire, 1 inch has to be added to the width of the wheel to get the correct backspacing for centering( backspacing is measured off the back rolled edge of the wheel a 7 inch wheel is 8 inches wide from outside rolled edge to outside rolled edge). Eric on your wheel picks, if I put them on my Dart the 7 inch with 4.5 backspacing and 255/60 are centered. If I went to an 8 inch wheel on my Dart I would need 5 inches of backspacing to recenter the 255/60 tires and I have yet to find that backspacing in an 8 inch wheel other than custom made. A 275/60 will fit if you move the springs against the frame rails and pick up that 1/2 to 3/4 inch of space and then remeasure for backspacing to center the tire in the new space.
 
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