This backspacing doesn't sound right!!!

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doogievlg

doogievlg

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So I have a 1973 swing and I have had slicks on it for over a year now and decided to bite the bullet and order some new wheels so I can put my street tires on. The wheels that are on the slicks were orginialy on the street tires so I figured I could measure them and use that backspacing to order my new wheels. The backspacing on them is only 3.5 which seemed small to me. The tires are 235/60/15 and I thought I would ask around on here to make sure I am not screwing this home somehow. Thank you in advance for the input.
 
Are you measuring from the mounting surface to the lip of the wheel?

I'd think the b/s would be around 4 1/2" or 4 1/4" if it is a 7" wheel.

wheel_offset.jpg
 
Well if you own the car and the wheels are on there now, I think you answered your own question? No?
 
SGBARRACUDA said:
Well if you own the car and the wheels are on there now, I think you answered your own question? No?
Click to expand...

I just assumed there would be more backspacing. Also I'm unsure of what width to get since I don't know the width of the current wheels and can't measure them while they are mounted.
 
Well not sure which wheels are on your car. But a stock ralley wheel is only 5.5-6 inches wide. So 3 1/2" back spacing would be about right.
 
The only wheels that have been mounted to this rear end while on my car are the solid aluminum centerline wheels. I am going to a crager and was thinking a 7 or 8 inch wheel. I just really do not want to go through the trouble and have these things rub.
 
With the springs in the stock location, I think your asking for a headache with the 8" wheel.
 
A seven inch wheel is really 8" overall. Look under your car now and see if one more inch of backspacing will still clear everything. If so I think 4.5" BS would be better. Try and measure the outside to outside of the wheels you have now and then see how that size will work or fit with the 8" overall of a 7" wheel. Don't forget that the tires you mount will also bulge past the rim so take that into account also.
 
Thanks I didn't think to measure the gap between the tire and leaf spring. Right now there isn't much room on the fender side at all so I think a little more back spacing would help.
 
doogievlg said:
I just assumed there would be more backspacing. Also I'm unsure of what width to get since I don't know the width of the current wheels and can't measure them while they are mounted.
Click to expand...

The wheel width should be stamped or cast somewhere on the backside. Also, the wheel width can be measured. Lip-to-lip width is almost always exactly 1" greater than the "wheel width". You might have to lay something like a foot long 1x3 board across each lip, measure the width between the boards, and then subtract the width of the 2 boards, and then subtract 1".
 
69_340_GTS said:
The wheel width should be stamped or cast somewhere on the backside. Also, the wheel width can be measured. Lip-to-lip width is almost always exactly 1" greater than the "wheel width". You might have to lay something like a foot long 1x3 board across each lip, measure the width between the boards, and then subtract the width of the 2 boards, and then subtract 1".
Click to expand...

This can be done with the tire on?
 
doogievlg said:
This can be done with the tire on?
Click to expand...



how would you get the rim flat on a board or anything else when the tire bulges out farther than the wheel ?? wouldn't the tire always hit the ground first. I'm sure there are ways to fan dangle it. But with such an investment hinging on good exact measurements wouldn't it be worth the time and few dollars to pull the wheel off and take it to ur local place to dismount the tire and get good accurate measurements off just the wheel.
 
You can easily & accurately measure from the bulge of the tire to the edge of the wheel/rim. From there it's just simple addition & subtraction.
 
doogievlg said:
This can be done with the tire on?
Click to expand...

Take your tire/wheel assembly to any tire store. They'll have a tool to measure the wheel width without removing the tire.

If you were closer, I'd lend you mine...
 
I think the wheel well on a 69 is the same. I put on a 7 inch rim with 4 1/4 backspace. Used a 245/60/15 tire. Maybe a finger between the tire and the leaf spring. Same on the outer fender.
 
furyus2 said:
I think the wheel well on a 69 is the same. I put on a 7 inch rim with 4 1/4 backspace. Used a 245/60/15 tire. Maybe a finger between the tire and the leaf spring. Same on the outer fender.
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Your right the wheel wells are the same as long as the same rear end is in both cars.
 
6pk2goDemon said:
Take your tire/wheel assembly to any tire store. They'll have a tool to measure the wheel width without removing the tire.

If you were closer, I'd lend you mine...
Click to expand...

I'm going to pop the wheel off tonight and run it over to tire discounters. I just want to get these street tires on so I can go out in my car without worrying about getting stuck with slicks in the rain.
 
SGBARRACUDA said:
Your right the wheel wells are the same as long as the same rear end is in both cars.
Click to expand...

8 1/4 read end! I'm just going to get the same demminsons as the wheels that came with the rear end since I know for a fact they work with those tires.
 
doogievlg said:
8 1/4 read end! I'm just going to get the same demminsons as the wheels that came with the rear end since I know for a fact they work with those tires.
Click to expand...

Well that is the safe thing to do. I have a 8 1/4 in my 69 with Ralley 14 x 6 wheels. I know I have room in there for a wider wheel but not sure how much.
 
hear is our 70 dart. 8 3/4 rear. big bolt axles and big car brakes so its a hair wider then a stock small bolt 8 3/4.


15x7 rim with 4.5 backspace. if i knew before hand i would have went 4 3/4 backspace.

DSC_0279-1.jpg


DSC_0280-2.jpg
 
hear is our 69 dart. 8 3/4 rear. big bolt axles and big car brakes so its a hair wider then a stock small bolt 8 3/4.

17x8 with 5.72 backspace.

DSC00036.jpg


DSC00037.jpg


DSC00034.jpg


DSC00039.jpg


DSC00038.jpg
 
abodyjoe said:
hear is our 70 dart. 8 3/4 rear. big bolt axles and big car brakes so its a hair wider then a stock small bolt 8 3/4.


15x7 rim with 4.5 backspace. if i knew before hand i would have went 4 3/4 backspace.

DSC_0279-1.jpg


DSC_0280-2.jpg
Click to expand...

That is pretty much what I was thinking that 7" is what will fit without running into trouble.
 
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