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  •  » tire dimension

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    3/12/2023 1:01 PM  #1

    retired65
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    Registered: 6/18/2020
    Posts: 36

    tire dimension

    I have a question about some different tire dimensions.  What would the tire width be in fractions, not mm's between 215/60R15 and 225/60R15 tires.  Not the width of tread, but the widest part of the tires?  Thanks

     

    3/12/2023 4:12 PM  #2

    Nos681
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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
    Posts: 3,058

    Re: tire dimension

    Take the section width (215mm or 225mm) and divide by 25.4mm.
    This will be your theoretical widest part of the tire.

    I take the decimal portion and multiply by 2, 4, 8, or 16.
    That will be your numerator (top number) for fractions.

    Keep in mind that each manufacturer might be slightly different in size even with same “tire size.”

    Kelly and Pirelli tires run small in section width compared to the BFG and Cooper.
    Just my experience and measurements taken in the past.

    My BFG’s 235/60/14 = 9.25”
    My Pirelli’s 235/40/18 = 9”

    Last edited by Nos681 (3/12/2023 4:15 PM)

     

    3/12/2023 8:46 PM  #3

    RPM, aka Bearing Bob
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    From: Bakersfield, Ca
    Registered: 9/17/2013
    Posts: 3,249

    Re: tire dimension

    retired65 wrote:

    I have a question about some different tire dimensions.  What would the tire width be in fractions, not mm's between 215/60R15 and 225/60R15 tires.  Not the width of tread, but the widest part of the tires?  Thanks

     

    Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
     

    3/12/2023 9:19 PM  #4

    MS
    Forum Originator

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    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 11,731

    Re: tire dimension

    retired65 wrote:

    I have a question about some different tire dimensions.  What would the tire width be in fractions, not mm's between 215/60R15 and 225/60R15 tires.  Not the width of tread, but the widest part of the tires?  Thanks

    215 is the cross section of the tire ON A SPECIFIC WIDTH OF RIM.  Just ask siri to convert 215 millimeters to inches. That will give you the cross section of the tire at its widest point in inches.  Of course, the cross section changes a bit depending on the rim width the tire is mounted on.
    Then multiply that result times the aspect ratio to get the sidewall height from rim bead to outside of tread.

    Multiply that height by two and add the rim diameter to get the overall height.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    3/12/2023 10:23 PM  #5

    Nos681
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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
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    Re: tire dimension

    225/60/15

    225mm➗25.4mm🟰8.86 inches (section width)   (25.4 mm🟰1 inch)

    8.86✖️.60🟰5.31 inches (section height)

    5.31✖️2🟰10.62 inches (top and bottom of tire height)

    10.62➕15🟰 25.62 inches (overall tire height)


    As mentioned earlier, some tire manufacturers are close to these dimensions…some run narrow and some run wider.

    This will also include overall tire diameter as well.

    Depending on manufacturer and style of tire, you might have to go up or down a size.

    I know most tire manufacturers also list revolutions per mile.
    The fewer revolutions, the larger the diameter.
    More revolutions, smaller diameter.

    I have seen same size tire by same manufacturer have different revolutions per mile due to different style tire.
    Such as all season, summer performance, off-road, etc.

     

    3/13/2023 10:20 AM  #6

    BobE
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    From: White Plains, NY
    Registered: 4/04/2013
    Posts: 2,200

    Re: tire dimension

    1mm=0.03937"
    225-215=10mm
    10mm=0.3937"
    3/8"=0.375"
    25/64"=0.391

    Link to on-line conversion calculator: https://www.unitconverters.net/

    65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
     

    3/13/2023 10:57 AM  #7

    RPM, aka Bearing Bob
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    From: Bakersfield, Ca
    Registered: 9/17/2013
    Posts: 3,249

    Re: tire dimension

    I like MS's math better. 🤪

    Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
     

    3/13/2023 12:38 PM  #8

    6sally6
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    From: Surfside Beach,SC
    Registered: 4/02/2013
    Posts: 6,460

    Re: tire dimension

    Real world answer (maybe!?!)
    I rolled my fender lips and 225-50-15 would scrub when turned sharp going in a driveway(barely)
    Switched to 215 65-15 and 'still' get one tire singing (rear) when I hit a dip in da road. (shocks would prolly fix it)
    All-in-all no 'major' scrub issues with either.
    Final answer.......hardly ANY difference between the two sizes.
    Shocks make a difference....tire manu. makes a difference.... road conditions are a factor....
    Visually.......hardly noticeable unless you get down and read the sizes 225-60 vs 215-60...215-65.
    Crap shoot..........
    6sally6

    Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
     

    3/13/2023 3:19 PM  #9

    retired65
    FYI FORD Member

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    Registered: 6/18/2020
    Posts: 36

    Re: tire dimension

    Thanks everyone for the help.

       •Thread Starter
     

    3/14/2023 7:36 AM  #10

    MS
    Forum Originator

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    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 11,731

    Re: tire dimension

    6sally6 wrote:

    Real world answer (maybe!?!)
    I rolled my fender lips and 225-50-15 would scrub when turned sharp going in a driveway(barely)
    Switched to 215 65-15 and 'still' get one tire singing (rear) when I hit a dip in da road. (shocks would prolly fix it)
    All-in-all no 'major' scrub issues with either.
    Final answer.......hardly ANY difference between the two sizes.
    Shocks make a difference....tire manu. makes a difference.... road conditions are a factor....
    Visually.......hardly noticeable unless you get down and read the sizes 225-60 vs 215-60...215-65.
    Crap shoot..........
    6sally6

    Having wheels with the correct backspacing for the car is equally as important as tire size.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    3/14/2023 7:15 PM  #11

    Nos681
    Senior 24-7 FYI Addict

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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
    Posts: 3,058

    Re: tire dimension

    MS wrote:

    6sally6 wrote:

    Real world answer (maybe!?!)
    I rolled my fender lips and 225-50-15 would scrub when turned sharp going in a driveway(barely)
    Switched to 215 65-15 and 'still' get one tire singing (rear) when I hit a dip in da road. (shocks would prolly fix it)
    All-in-all no 'major' scrub issues with either.
    Final answer.......hardly ANY difference between the two sizes.
    Shocks make a difference....tire manu. makes a difference.... road conditions are a factor....
    Visually.......hardly noticeable unless you get down and read the sizes 225-60 vs 215-60...215-65.
    Crap shoot..........
    6sally6

    Having wheels with the correct backspacing for the car is equally as important as tire size.

     
    BS is your friend Sal. 😜

     

     

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