Spring re-location?

[496dart]

These are the tires i'll most likely go with, i'm sure they'll hook, i'm planning on clamping the springs, running a snubber & good shocks. The 27" should work great with 3.73s don't ya think?

http://www.jegs.com/i/Mickey-Thompson/672/3756R/10002/-1?parentProductId=753925#

i think you are on the right track !

you wont need the snubber (unless you have a stick car) --save your $

 

[pettybludart]

Just to clarify, because I think there's a lot of confusion in this area.

There is a difference between offset & backspace. Offset is the amount the mounting surface has been moved from the centerline of the wheel. Positive offset moves the mounting surface towards the outer side of the wheel, giving a shallower dish to the wheel. Negative offset moves the mounting surface the opposite direction, resulting in a deeper dish.

Backspacing is the measurement from the back edge of the wheel to the mounting surface.

As an example, a 7" rim with a 3.5" neg. offset would have about 1/2" backspacing. The 7" wheel is about 8" wide. 3.5" offset moves the mounting surface from the center of the wheel toward the brake drum 3.5". 8" divided by 2 gives 4" from the center of the wheel to each edge. 4" minus 3.5" offset = 1/2" backspace.

I think offset is a more accurate number because, when using backspacing, it is assumed that the total wheel will be 1" wider than the specified width. Whereas, offset always measures from the center of the wheel. If you know that the brake drum/disk wheel mounting surface is 1.5" from the center of the wheel tub, you know a 1.5" offset in the correct direction will center the tire. If you used backspacing, a 7" wheel would put the tire in a different spot than an 8" wheel with the same backspacing. If a 7" wheel with 1.5" pos. offset centers your tire the wheel would have a backspacing of about 6". For an 8" wheel to center the tire you would need a backspacing of about 7". This seems counter-intuitave because it looks like the larger wheel would move the tire closer to the spring because it has more backspace. You have to keep in mind that while the back edge of the wheel gets closer to the spring, the center of the tire stays in the same place.


I hope I did all of the math correctly. :read2: Someone straighten it out if I'm wrong. :munky2:

Thanks for the writeup 64Cuda,I did a google search on backspacing for some more info. on this.Thanks again.

 

['64 Cuda]

Did I get the math right? I sat here drawing pictures & second guessing myself the whole time I was typing. #-o

 

[JoeDust451]

I had a used 245/60/15 lying around (without a rim), so i decided to do some mocking, i sat the tire in the well & centered it (takeing the drum off), with the edge of the tire about 1/4" or so from the springs, its showing just shy of 4.25" for back spaceing, but theres a good 1.1/4" from the outer tires belly to the lip molding ( i'm good there), so it doesn't look like a 15x8" wheel with a 4.5" BS will work, i'm sure a 255/60/15 will fit, but on a 4.25 BS at max (maybe), looks like a 15x7" with 4" BS would work best, from what i've heard around the boards, thats what most are running with stock wells & spring location with a 255/60/15 MT, the 245/60/15 has about a 10.1/4" section.

The 255/60/15 MT has a 10.7" section, & the rim sizes are 7-9" recammended, don't know what size rim they mounted it on to come up with the 10.7" section, maybe it was an 8"

 

[340 GORDIE]

I have a 1970 swinger with the offset hanger, rolled outer lip and thats all... I fit a 15 x 8.5 wheel with 5" backspace with a 275 / 60 M/T drag radial. it is only a few hairs from touching the lip AND the super stock spring, but it "fits" and I drive it to the track, pound off a string of 11:00's and drive home.

 

[tubtar]

When you open up the wheel wells , save your self some pain and use 8 to 10 " strips rather than one long piece to fit in there.
You can thank me later.
I have an early A body , so the numbers will vary from a later chassis.
Leafs moved to the frame rails , axle housing shortened 2" per side.
Axle moved rearward 3/4 "
10 " rim with 6 1/2 " back spacing , 295-55 X 15 drag radial and room to spare.......I could possibly stuff a 315 in there if I don't change the diameter.