<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">To determine the size of the old tire in modern designation format measure the tread width in millimeters, I’m guessing 5.5 inches times 25.4 = 140, that’s your first number.<div><br></div><div>I’m guessing 9.20 is the dimension in inches of the top side wall + The bottom side wall. When added to the 15 inch wheel diameter it would give you a tire diameter of 24.20 inches. This is just a guess of what they mean by 9.20.</div><div><br></div><div>Next, Measure the side wall height in millimeters, I’m guessing 9.20 inches/2 x 25.4 = 117mm. Divide 117 sidewall height by the 140 tread width gives you a height to width ratio of 1.20 which is your second number... but they don’t show the decimal so it reads as 120.</div><div><br></div><div>So the old 5.50-9.20-15 = a new 140-120-15 (if my guess of what 9.20 means is correct, if not, just measure the sidewall as my 120 number would be wrong).</div><div><br></div><div>It appears that the old tire is 1.7 inches narrower than your new 185-65-15 and there is only 1/10 of an inch difference in the tire height.</div><div><br></div><div>Dustin<br><br><div id="AppleMailSignature" dir="ltr">Sent from my iPhone</div><div dir="ltr"><br>On Jun 27, 2019, at 1:19 PM, Redmond via Fot <<a href="mailto:fot@autox.team.net">fot@autox.team.net</a>> wrote:<br><br></div><blockquote type="cite"><div dir="ltr">
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<p style="font-family: Helvetica;">I should've been a little bit more clear than mud. <br></p><p style="font-family: Helvetica;">I'm just curious as to what the size tire he was running back in the 1960's. Can anyone translate the 5.50-9.20-15 into today's sizing.<br></p><p style="font-family: Helvetica;">FYI - I'm going with the 185-65-15<br></p><p style="font-family: Helvetica;">Todd<br></p><p style="font-family: Helvetica;"><br></p><p style="font-family: Helvetica;"><br></p><blockquote type="cite">On June 27, 2019 at 11:08 AM Redmond via Fot <<a href="mailto:fot@autox.team.net">fot@autox.team.net</a>> wrote: <br> <br><p style="font-family: Helvetica;">Friends,<br></p><p style="font-family: Helvetica;"><br></p><p style="font-family: Helvetica;">Curious question:<br></p><p style="font-family: Helvetica;">I have 1 Goodyear Blue Streak tire from when my dad raced my TR3.<br></p><p style="font-family: Helvetica;">Size says 5.50-9.20-15<br></p><p style="font-family: Helvetica;">What size would this be in today's sizing?<br></p><p style="font-family: Helvetica;">Thanks<br></p><p style="font-family: Helvetica;">Todd<br></p></blockquote><p style="font-family: Helvetica;" class="default-style"><br> </p><blockquote type="cite">_______________________________________________ <br><a href="mailto:fot@autox.team.net">fot@autox.team.net</a> <br> <br><a href="http://www.fot-racing.com">http://www.fot-racing.com</a> <br> <br>Donate: <a href="http://www.team.net/donate.html">http://www.team.net/donate.html</a> <br>Archive: <a href="http://autox.team.net/archive">http://autox.team.net/archive</a> <a href="http://www.team.net/pipermail/fot">http://www.team.net/pipermail/fot</a> <br>Unsubscribe/Manage: <a href="http://autox.team.net/mailman/options/fot/alfetta95@optonline.net">http://autox.team.net/mailman/options/fot/alfetta95@optonline.net</a> <br> <br> <br></blockquote><p style="font-family: Helvetica;" class="default-style"><br> </p>
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