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DougN · 05-31-2001, 02:52 PM

Fast -

Tire size is a little wierd. The 50-60-70-75 numbers in the tire size are aspect ratios, or what percentage of the tire width the sidewall height is. On a tire sized as 255/70R15 255 would be the width of the tire in millimeters, 70 would mean the sidewall height is 70% of the tire width and r15 is the size of the rim the tire is to be mounted on. To convert millimeters to inches, divide the number by 25.4 - 255/25.4= 10 inches. 10 inches * 70%= 7 inch sidewall height. 7 inch sidewall height * 2 = 14 inches + 15 inch rim diameter = 29 inches of tire height.

05-31-2001, 02:52 PM	#3
DougN High Speed, Low Drag..... Join Date: Mar 2000 Location: Madison, SD, USA Posts: 358	Fast - Tire size is a little wierd. The 50-60-70-75 numbers in the tire size are aspect ratios, or what percentage of the tire width the sidewall height is. On a tire sized as 255/70R15 255 would be the width of the tire in millimeters, 70 would mean the sidewall height is 70% of the tire width and r15 is the size of the rim the tire is to be mounted on. To convert millimeters to inches, divide the number by 25.4 - 255/25.4= 10 inches. 10 inches * 70%= 7 inch sidewall height. 7 inch sidewall height * 2 = 14 inches + 15 inch rim diameter = 29 inches of tire height. __________________ '72 Chevy lwb fleetside "Winners never quit, and Quitters never win......but those who never win AND never quit are idiots."