What wheel backspace or offset do I need?

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by Big Dave, Jun 19, 2014.

  1. Big Dave

    Big Dave Veteran Member

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    I'm thinking about getting a set of 15x7 Cragar SS mags for my '76 LT, and maybe 235/60-15s for the rear and maybe 205/60-15s in front. The suspension is stock. What backspacing or offset would I need for the wheels?

    Thanks!
     
  2. fhp1556

    fhp1556 Veteran Member

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    Well, considering factory rims are 15x7 w/a 4 1/4" backspacing and most people run w/a minimum 235/60 R15 at all four corners, I personally wouldn't put anything smaller on my ride. I would go w/a 15x8 rear wheel and 245 or 255/60 R15 if it were me.
     
  3. Big Dave

    Big Dave Veteran Member

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    The factory original rally wheels are 14x7s. I'm currently running 215/70-14s but need to replace them due to their being 15 yrs old now, so I was thinking of getting the 15 inch mags. The Cragars come in 4.125 or 4.0 inch backspacing, I think. If the original 14x7s have 4.25 inch backspace, would I want the 4.125s for 15x7s?
    If I ran 15x8s on the rear, what backspace would I want? An additional 1/2 inch to cover the extra 1 inch of wheel width?
     
  4. wayback

    wayback Veteran Member

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  5. The Champ

    The Champ Veteran Member

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    The original tires on your 76LT were FR78x14's which were 26.5" tall.

    Your current tires are 25.9" tall.

    A 205/60/15 is only 24.7" tall and is skinnier than current your 14's are. Way too small for a Camaro.

    A 235/60/15 is 26.1" tall shorter than the OE tires, and just a bit taller than your current tires - and should work fine on all 4 corners with the 4.125" BS.

    On the rear I'd personally want to run a tire closer to the original tire height to keep my speedometer more accurate. A 245/60/15 is 26.6" tall - and that will work fine on a 15x7" rim with 4.125" BS.
     
  6. Big Dave

    Big Dave Veteran Member

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    Thanks, guys.
    It looks like Wheel Vintiques and US Wheel make chrome wheels that look very similar to the Cragar SS... anyone know how they compare in quality to the Cragars?
     

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