R REDSXYGT New Member Apr 17, 2003 44 0 0 Texas Feb 10, 2004 #1 Feb 10, 2004 #1 What's that formula to find the diameter of the wheel? I'm trying to figure out these diameters: 275/40/17 or 275/40/18
What's that formula to find the diameter of the wheel? I'm trying to figure out these diameters: 275/40/17 or 275/40/18
W Wi-Stanger New Member Oct 18, 2003 111 0 0 Wisconsin Feb 10, 2004 #2 Feb 10, 2004 #2 the 17 is 1 inch shorter than the 18, the number 40 in that is the sidewall height. As for actual diameter I'm not sure.
the 17 is 1 inch shorter than the 18, the number 40 in that is the sidewall height. As for actual diameter I'm not sure.
00s281sc368 New Member Dec 14, 2003 532 0 0 Fremont, CA Feb 10, 2004 #3 Feb 10, 2004 #3 275 is the tire width on the road, in millimeters, divide by 25.4 to get in inches 40 is the sidewall height, in percentage of the width, so it means 40% of 275mm 18 is the diameter in inches...units are kind of mixed up ... 275 = millimeter 40 = % 18 = inches So the wheel diameter in inches would be : 275/40/17: 17 + (275x0.40/25.4 x2) = 25.66 inches 275/40/18: 18 + (275x0.40/25.4 x2) = 26.66 inches
275 is the tire width on the road, in millimeters, divide by 25.4 to get in inches 40 is the sidewall height, in percentage of the width, so it means 40% of 275mm 18 is the diameter in inches...units are kind of mixed up ... 275 = millimeter 40 = % 18 = inches So the wheel diameter in inches would be : 275/40/17: 17 + (275x0.40/25.4 x2) = 25.66 inches 275/40/18: 18 + (275x0.40/25.4 x2) = 26.66 inches
nickthegenius Active Member Dec 23, 2002 1,631 1 38 Elwood, IN Feb 10, 2004 #4 Feb 10, 2004 #4 Here is a handy calculator. Yeah, its on a Miata site, but it works http://www.miata.net/garage/tirecalc.html
Here is a handy calculator. Yeah, its on a Miata site, but it works http://www.miata.net/garage/tirecalc.html