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Rear tire sizes: 305/45-18 vs 305/40-18

Discussion in 'SVT Shelby GT500' started by ///Bruce, Dec 26, 2014.

  1. ///Bruce

    ///Bruce ///Bruce Established Member

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    If you look at Nitto 555R's, the 45 will fit on a 9.5" rear. But the 40 will not fit unless it's 10" wide. Anyone get the 305/40-18's to fit on a stock 18x9.5 rim?
     
  2. black99lightnin

    black99lightnin move along Established Member

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    makes no sense. 305 is the width. 45/40 is the height as a percentage. The 45 is pretty tall and what is used for Lightnings.
     
  3. ///Bruce

    ///Bruce ///Bruce Established Member

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    I thought the same thing. But look at Nitto site. The 45's will fit on a 9.5" rim but the 40's begin on a 10" rim. It might be because of the additional width.

    Why I would want to do this is because the OD is right at 27". Perfect diameter relative to the front size.
     
  4. stkjock

    stkjock Corn Powered 900 HP! Established Member

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    the bigger aspect ratio allows a fitment on a narrower rim due to the size of the side wall.

    the 40s will fit on a 9.5" but it's less than optimal and will bulge more
     
  5. ///Bruce

    ///Bruce ///Bruce Established Member

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    Thank you for the explanation. Now the questions begs will the 40 fit with no rubbing issues...
     

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