Tire size for rear of 69 gs?

Discussion in 'The Hides' started by dan zepnick, Sep 8, 2021.

  1. dan zepnick

    dan zepnick Well-Known Member

    What can you fit under the rear? Has 215/70/15's on it now.
     
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  2. Premier 350

    Premier 350 Chris (aka Webby)

    225/70/15s on Buick Rallys on mine. No issues.
     
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  3. Mike B in SC

    Mike B in SC Well-Known Member

    245/60-15's fit nice on my 68.
     
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  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    It depends on the back spacing and width of rim you use. 15" wheels never came on a 1969 A body as near as I can tell. On a 7" wide wheel, I say you need 5" of back space minimum to fit the widest tire possible.

    I base my conclusion on the Rallye wheel chart in this Forum. The 1968-70 14 X 6" wheel has 4 3/8" of back space. A 7" wide wheel would need 1/2" more back spacing to center the wheel/tire as stock. That's 4 7/8".
     
    Last edited: Sep 8, 2021
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  5. mbusher83

    mbusher83 Well-Known Member

    I have 15x7 with 4” backspacing and bf Goodrich L60’s on the back of my 69 skylark. No issues, I think it’s similar to a 275/60/15 but the L60’s are an inch shorter.
    upload_2021-9-8_9-30-33.jpeg
    upload_2021-9-8_9-32-1.jpeg
     
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  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Mark, have you actually measured that back spacing? That contradicts everything I know about back spacing requirements for the pre 1970's cars. No stock 15 X 7" wheels had 4" of back spacing, so those wheels have to be reproductions. I don't understand how they can fit with L60-15 tires.
     
    Last edited: Sep 8, 2021
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The L60-15 has a section width of 10.50"(266.7mm) and a tire height of 27.86". A P275/60R-15 has a section width of 275mm (10.8"), and a tire height of 27.99". The measurements can vary a small amount depending on the rim width they are mounted on. So an L60-15 is actually a little smaller by the numbers. It may appear bigger because of the overall tire construction. The G60-15 has a bigger look than the P245/60R-15 even though they are very close in measurement.
     
    Last edited: Sep 8, 2021
  8. mbusher83

    mbusher83 Well-Known Member

    They are reproductions Larry. 15x7’s from Coker tire if I remember correctly. I’ll pull one off and measure it again this weekend.
     
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  9. Eric

    Eric Founders Club Member

    I have 4ea 1970 Buick 15×7 WG rims with BFG
    245/60-15's on my 69 convertible.
    No issues whatsoever! Don't remember what the backspacing is from the factory.
    20210227_223221.jpg
     
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  10. Jeff Pulera

    Jeff Pulera Well-Known Member

    I had 275/60 rears and that was a bit too much, tight quarter lip clearance. Went to 17x9 with 275/40 and have more clearance now due to proper backspace/offset
     

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