Tire size calculation

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  • Shwartz

    #1

    Tire size calculation

    So I know that Tire threads are done to death but when I did a search, I couldn't find what I need.

    Does anyone have a link (or can explain) to a good tire size calculation?

    The factory spec:
    Front - 3.25H19 4PR
    Rear - 3.75H18 4PR

    What's on there now:
    Front - 3.25 V19
    Rear - 120/80 VB18

    How do I make the comparison from what is supposed to be on there, to what I should actually be ordering.
    From what I understand it's simply a conversion from Metric to imperial?

    Please clarify.
  • GateKeeper

    #2
    it's all here....



    then go to here



    and see here



    lots of good stuff for you.....

    and one more good read



    .
    Last edited by Guest; 02-13-2013, 10:36 AM.

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    • Steve
      GS Whisperer
      • Jun 2005
      • 35925
      • southwest oHIo

      #3
      I think the front tire actually translates to a 90/90-19, but if you install a 100/90-19, it will remove most (if not all) of your speedometer error.

      A 120/90-18 would be correct for the rear.

      Normally, yes, it would be a simple conversion from metric to Imperial, but they have changed the way they label tires a few times since these bikes were made, so the remaining tires just add to the confusion.

      .
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      Comment

      • Shwartz

        #4
        Originally posted by Steve
        I think the front tire actually translates to a 90/90-19, but if you install a 100/90-19, it will remove most (if not all) of your speedometer error.

        A 120/90-18 would be correct for the rear.

        Normally, yes, it would be a simple conversion from metric to Imperial, but they have changed the way they label tires a few times since these bikes were made, so the remaining tires just add to the confusion.

        .
        According to Basscliff's chart, wouldn't it be closer to 110/90-18 for the rear? Does the 110/90 vs the 120/80 on it make a difference? So the 120/80 that's on it would just be a fatter tire with a lower sidewall?

        Comment

        • Guest

          #5
          Better a lower sidewall than a higher profile.

          Comment

          • BassCliff

            #6
            Hi,

            On the rear you could use the 110/90 or 120/90 with very little difference between. My tire size converts to a 120 but I run a 130 and it works well. The same goes for the front. Right now I have a 100 but have used a 110. It makes a bit more difference for me on the front. The larger tire seems more "planted" and stable on the freeway but the skinnier tire is a little easier to throw around in the twisties.


            Thank you for your indulgence,

            BassCliff
            Last edited by Guest; 02-13-2013, 04:13 PM.

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