Yet another backspace thread

Tires and Wheels (Mopar Hubcaps Too)

  1. Mark Barnes

    Mark Barnes Well-Known Member

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    Well, I pretty well screwed myself again. Measured, (or thought I did) rear wheel openings on the Belvedere II with the intent of putting 270/60-15's under there. Bought 15x8, 5x4.5, 4.5" bs steel wheels and thought I was rolling.
    NOPE. I was a little off with my measurement. 1/4" off? NOPE. Off by a full inch, maybe more.
    I guess I should have figured it out when I had to unbolt the leaf springs at the rear and drop the axle to even get it close to getting the wheel in there. Then once I got the wheel on, I had a full 1.5" from the inside of the tire to the leaf spring.
    Damn. Rubbing HARD on the inner lip of the wheel well too. You can easily see it in the pics.
    One more inch of BS will put me 1/2" off the leaf spring, and looks like it will get me inside the wheelwell.
    Question is, has anyone had to go 5-1/2" on the BS? Is 1/2" enough clearance from the spring? Everyone I talked to, and everything I read says 4-1/2" was the magic number...but apparently not for this car. Well, look for a couple brand new steel wheels to show up in the "for sale" section....

    20210729_143025.jpg 20210729_142915.jpg 20210729_142934.jpg 20210729_134702.jpg
     
  2. VANDAN

    VANDAN FBBO Gold Member FBBO Gold Member

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    Maybe try a 15x7" rim, with that BS. I think those tires will fit those rims ?
     
  3. moparedtn

    moparedtn Ed on the Ridge FBBO Gold Member

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    I believe the "magic" 4 1/2" is for the next generation b-bodies from yours?
     
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    • 747mopar

      747mopar FBBO Gold Member FBBO Gold Member

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      Looking at your pictures it sure seems like no matter the backspacing your going to have trouble, looks like it's going to be rubbing on both sides or damn near even with perfect backspacing. What's the overall width of the tire vs wheel opening including the sidewall pucker? Backspacing is one of the easiest things to measure so don't ask people just get under there and measure.
       
    • Mark Barnes

      Mark Barnes Well-Known Member

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      Apparently. What a colostomy. (Like Norm Crosby used to say)
       
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      • Stanton

        Stanton Well-Known Member

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        Did you check the BS on the wheels ?? The way I figure it you should be OK with what you ordered.

        FWIW a 10" wheel with 5-1/2 BS will fit my '69. I your case you've knocked an inch off each side of that AND your axle is a tad narrower than a 69. You should be able to get that in there with plenty of clearance.
         
      • Mark Barnes

        Mark Barnes Well-Known Member

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        Yeah, the BS measures 4-1/2". It looks like I can get it in there with 5-1/2". And I wish my axle was even a little more short!
         
      • VANDAN

        VANDAN FBBO Gold Member FBBO Gold Member

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        Is that the stock, or Year/Model correct rear end in the car ?
         
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        • 65wgn440

          65wgn440 Well-Known Member

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          I have a '67 Belvedere and am currently running 275/60/15 on factory 7.5" steel wheels with 4.5" backspace. Tires fit perfectly, but my rear ride height is taller than stock, which helps. I have a set of same size drag radials I want to put on car with 8" rims, so I've researched this subject for awhile, to keep from wasting money. From what I've found, as you now know, 4.5" ain't gonna happen on 8" wheels. I've been told that 5.25" -5.5" is working for SOME people ( mostly drag race guys I've talked to at track). So many variables in the equation. '67's apperently had a slightly narrower axle housing than the next generation, so if axle was ever swapped with later housing, all bets off. I have decided on my mostly street car, that the 7.5" wide rims are going to have to do, rather than all the headaches trying to fit 8". BTW, I also ran factory steel 7" wide wheels with the 275/60/15 tires, also no problems.
           
        • 33 IMP

          33 IMP Well-Known Member

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          I'm guessing someone changed to a later model 8 3/4 (took out a 7 1/4 maybe?). Do some research and measurements. The wheel you have should work. Im betting your rear is wider by a couple inches.
          I would say a seven incher is probably a better fit. 66s and 67s have tight wbeelwells.
           
          Last edited: Jul 30, 2021
        • #41

          #41 Well-Known Member

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          This is why you always, always, always measure for yourself. You never know if you've had an axle swap or the guy that is advising you did.

          1/2" away from the spring is fine. You can go to a 1/4" but I prefer a little more room than that. It looks to me that you might end up with inner fender clearance problems getting that close though. Sorry, I have never owned a 67 B, so I cannot help with specific examples.
           
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          • Mark Barnes

            Mark Barnes Well-Known Member

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            Hmmm...I bought a set of 7" wheels for the front. Wonder if they'll work on the rear?
             
          • Mark Barnes

            Mark Barnes Well-Known Member

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            Yep, gonna try the 7" set on the rears. Hope it works.
             
          • Fran Blacker

            Fran Blacker FBBO Gold Member FBBO Gold Member

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            As said earlier the 8" rim reamed you.:DHad L60 x 15's on 7" rims 4" BS rubbed on hard corners.
             
          • Aron Gleason

            Aron Gleason Well-Known Member

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            I have 15x8 wheels with 4 3/4 backspace, 275/60/15 drag radials on a 67 coronet. Stock wheelwells .and no rubbing.
             
          • Mark Barnes

            Mark Barnes Well-Known Member

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            Good question. Gonna measure it tomorrow.
             
          • 66383

            66383 FBBO Gold Member FBBO Gold Member

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            Where did you get 15/8 wheels with 4 3/4 bs?
             
          • Aron Gleason

            Aron Gleason Well-Known Member

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            I have 4 3/4 backspace on my wheels. I had figured on that backspacing after using different thicknesses of wheel spacers.
             
          • Mark Barnes

            Mark Barnes Well-Known Member

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            Now it looks like 5-1/2" for me, but I'll try the 7" wheels first.
             
          • 33 IMP

            33 IMP Well-Known Member

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            This is exactly why i think he's got a non-stock rearend in it. Yours is a quarter inch different than his, yet his wheel is two inches from the spring!
             
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