Whos running 275/60r15. Having issues

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Carlb87

Carlb87

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So I had done a lot of research and kept coming up that a p275/60R15s fit on a stock Duster on 15x8 rims with 4.5 backspace. So I bit the bullet and purchased a set for a rear end I'm swapping into my Duster. This rear came out of a 74 factory 318 Duster. When I mounted the Wheels to the rear for a test fit one side rubs bad and the other is super close. Did I miss something on the specs?
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I would have done 4"-4.25 backspacing. If you get longer studs you can use a 1/4 spacer
 
That rearend looks narrowed to me
the U-bolts are way too close to the bearing housings. I'd say 1.5 inches per side maybe a tad more.
I narrowed mine 3 inches and still use 4.5 bs wheels no problem. My U-bolts are about a quarter inch from the welds, IIRC
 
The problem is that you’ve got an 8.25 or 7.25” rear axle. They’re not the same width as an A-body 8 3/4. In fact they’re about a full inch narrower. That’s a 1/2” per side that you don’t have, and that’s why those 275’s rub.

A 15x8 with 4.5” of backspace works for an 8 3/4 with BBP axles, not a 7.25 or 8.25.
 
72bluNblu said:
The problem is that you’ve got an 8.25 or 7.25” rear axle. They’re not the same width as an A-body 8 3/4. In fact they’re about a full inch narrower. That’s a 1/2” per side that you don’t have, and that’s why those 275’s rub.

A 15x8 with 4.5” of backspace works for an 8 3/4 with BBP axles, not a 7.25 or 8.25.
Click to expand...
Spot on.... I did relocate the D/ C weld on relocation perches, onto a original 8".75 " a body axle. It's tight with a 15 " by 8" , wheel ,with a 4 .5 back spacing, on a 275 BFG drag radial. It's tight ,but drivable
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Massage ...fender lips ,as needed...
 
72bluNblu said:
The problem is that you’ve got an 8.25 or 7.25” rear axle. They’re not the same width as an A-body 8 3/4. In fact they’re about a full inch narrower. That’s a 1/2” per side that you don’t have, and that’s why those 275’s rub.

A 15x8 with 4.5” of backspace works for an 8 3/4 with BBP axles, not a 7.25 or 8.25.
Click to expand...
Narrower than the 8 3/4"? The 8 1/4"? That is news to me.
 
Also what I found was the bodies are not the same, the production tolerance form the factory is sometime + or-1/4" or more.
 
Thanks for all of the replies. I guess I didn't realize that the 8.25 was a different length than the 8.75. So I guess I'll get it in the car and see if I have room for a small spacer until I get around to getting the correct rims. If not I guess I'll have to relocate the springs or go with a different tire.
 
I have an 8.25" A body axle in my Barracuda on stock rebuilt rear suspension, leaf springs bushings ect, and I have that tire/wheel combination on my car. It works fine, I laid it all out on the computer. I had my 15 X 8 rear wheels built with 4.25" backspace as I remember. I have about 2600 miles on this combination with no sign of any rubbing inside or outside.

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The 8.25" housing is actually wider back plate to back plate than the 7.25 or the 8.75 housing. I think that is how I was able to make mine work.
 
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DesertRat said:
I have an 8.25" A body axle in my Barracuda on stock rebuilt rear suspension, leaf springs bushings ect, and I have that tire/wheel combination on my car. It works fine, I laid it all out on the computer. I had my 15 X 8 rear wheels built with 4.25" backspace as I remember. I have about 2600 miles on this combination with no sign of any rubbing inside or outside.

View attachment 1715227974

View attachment 1715227975
The 8.25" housing is actually wider back plate to back plate than the 7.25 or the 8.75 housing. I think that is how I was able to make mine work.
Click to expand...
So it looks like I messed up on the backspacing then. I bought 4.5 instead of 4.25. I'll probably throw some .25" spacers as suggested in a previous reply until I can get a need set of rims.
Thanks for the help guys!
 
Carlb87 said:
So it looks like I messed up on the backspacing then. I bought 4.5 instead of 4.25. I'll probably throw some .25" spacers as suggested in a previous reply until I can get a need set of rims.
Thanks for the help guys!
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I am not a fan of spacers of any type. I will not use them period, engineer around them if you can.
 
DesertRat said:
I am not a fan of spacers of any type. I will not use them period, engineer around them if you can.
Click to expand...

Really? Hope you never own a dually pickup truck...

If you buy QUALITY spacers there is nothing wrong with them. I and other have logged 100's of thousands of miles with them and run the at the track as well. Roadrace guys use them. You are being silly. No one is encouraging him to use the local parts store slip on pot metal spacers.

Wheel Adapters, Wheel Spacers, Hub Rings, and much more! | Motorsport Tech
 
roccodart440 said:
Really? Hope you never own a dually pickup truck...

If you buy QUALITY spacers there is nothing wrong with them. I and other have logged 100's of thousands of miles with them and run the at the track as well. Roadrace guys use them. You are being silly. No one is encouraging him to use the local parts store slip on pot metal spacers.

Wheel Adapters, Wheel Spacers, Hub Rings, and much more! | Motorsport Tech
Click to expand...
Just stating my personal belief, not trying to denigrate any other methods. Not that I get everything right, I don't but I don't believe wheel spacers on a mid-60's car of any type are the right way. JMHO-----------
 
72bluNblu said:
The problem is that you’ve got an 8.25 or 7.25” rear axle. They’re not the same width as an A-body 8 3/4. In fact they’re about a full inch narrower. That’s a 1/2” per side that you don’t have, and that’s why those 275’s rub.

A 15x8 with 4.5” of backspace works for an 8 3/4 with BBP axles, not a 7.25 or 8.25.
Click to expand...
Oh crap, I missed the last pic; good catch Blu
 
So sounds like spacer are the way to go then. For those that have used them is there any you recommend?
 
I can't understand why anybody would run a 275 tire with a factory rear end. 275's are too big!
 
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