Front runners, back spacing.

Mopar Racers Forum

  1. Cope

    Cope Fusing with fire

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    I'm about to order new wheels and wood like to know about your front runners.
    It seems like with the limited width of a front runner the tire is gonna sit well inside the wheel house?
    I'm gonna order the most back space I can but on a 15x4 wheel it's not much.
    Also 1973 and up BBP is 5x 4 1/2 correct?

    Thanks for the advice.
     
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    • j par

      j par Well-hung Member

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      So I use modern inset rims off of a 05 Dodge Magnum for the street (got them with tires for two hundred bucks). I have an extra wide rear axle so that worked fine so I didn't need backspacing back there. But I needed to buy some 5 on 4 and 1/2 by 5 on 4 and 1/2 inch and a quarter adapters to make the fronts work. Later I paid a Machine Shop to hog the centers of this front rims out so they fit without the adapters. But when I was running those adapters I would just put my Front Runners on those with no problem.
       
    • flyfish

      flyfish C8H18+N2O = :-D

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      5 on 4.5 is correct for the bolt pattern. I believe my fronts are 15x3" rims or 15x4"...not sure, been a lot of years. Front tires are 165R15's if I recall correctly. I use radials because mine is a "street" car (and I have radials on the back).
       
    • 340doc

      340doc Well-Known Member

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    • 383Scampman

      383Scampman Well-Known Member

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      15x3 1/2 or 4 with 3 1/2 back space . Work great . Sucks trying to stop .
       
    • clinteg

      clinteg Well-Known Member

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      These were the 15x4’s I had with the stock style suspension. 1.625” backspacing.

      063-4.jpg
       
    • Cope

      Cope Fusing with fire

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      Looks good. The only back spacing available in the wheel I need is 1.75 so I should be fine right?

      Thanks!
       
    • clinteg

      clinteg Well-Known Member

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      Yes that will move the tire in just a hair and will be fine.
       
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      • Cope

        Cope Fusing with fire

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        What do you folks think about playing with the brake bias to put a little more in the rear?

        With having so much more tire on the back would that make sense or is that just dumb?
         
      • j par

        j par Well-hung Member

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        I'm not sure about that even though the tire is much skinnier all the weight is still getting transferred to the front when you stop.
         
      • clinteg

        clinteg Well-Known Member

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        With a bigger tire in back AND if you’re still running drums in back, you need at the minimum a proportioning valve. An adjustable proportioning valve would be even better. If you get and adjustable, take her to a dirt road and start applying the brakes. Adjust it until you start getting even pressure/locking up of the brakes.
         
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        • Cope

          Cope Fusing with fire

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          I'm looking at ordering a adjustable valve.
          What size fitting should I order it to fit?

          Thanks for the advice.
           
        • A body

          A body SLO-KID

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          Call Dr. Diff.... he’ll set you up!
           
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