Mel~ In the good old days, all you needed was the width (9.50 or "nine and a half inches") and the rim diameter (14 inches) Sometime in the '60s, they started using "aspect ratios", and metric measurements, where the width of the tyre from sidewall to sidewall (235 MM, for example) was multiplied by the aspect ratio ("78" would mean 78%, 70 is 70%, 60 is 60%, etc) and the rim size (Still measured in inches, usually) David C. Wilker Jr, USAF (Ret) From: "Mel Wyshynski" <mvwyshy@xxxxxxxxxxxxxxx> Subject: IML: Tires Date: Sat, 20 Dec 2003 07:26:18 -0600 Reply-To: mailing-list@xxxxxxxxxxxxxxxx This is a multi-part message in MIME format. ------=_NextPart_000_0031_01C3C6CA.8F5658C0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Hello All I note that one of the tire sizes offered for 1959 was 9.50 X 14. This omits the second number which is the height of the tire as a = percentage of the width. There must have been a standard at that time. I recall something about = the number 78 but??? Would someone clarify this for me please. Thank you. Mel