18 Inch Rim Homepage

Question: Will upgrading my wheel size from a stock 15 to a 17/18 inch rim require me to re calibrate my speedometers?

(Posted by: therundown2k3 on 2008-04-14 19:42:15)

Posted by: Country Boy on 2008-04-14, 20:18:08

Not necessarily. Here's what to do. Go to tirerack.com and hunt for any one of their 18 brands of tires. Go to a particular brand and open the word spec. On the far right you'll see a heading called RPM. In tire language this means revolutions per mile. If you go with a larger wheel diameter just look through the list for a lower profile tire and refer back to RPM.If you stay within 20 less RPM of your *ORIGIONAL tire size your spedometer will be only 1-2 miles slower. Remenber that larger diameter tires roll less revolutions per mile and will slow down your speedometer.

Posted by: crxlancer on 2008-04-14, 19:52:45

Not if the circumfrence of the new rim/ tire is the same as your old set. be careful when choosing rubber for your bigger tires, you have MUCH more to worry about than your speedometer. you could ruin your transmission if your wheel size is different.

Posted by: flea on 2008-04-14, 19:56:31

Maybe... depends on tire size Plus Zero 185/ 65-15 Plus One 205/ 50-16 205/ 55-16 215/ 50-16 Plus Two 205/ 45-17 215/ 40-17 215/ 45-17 Plus Three 215/ 40-18

Posted by: wayne on 2008-04-14, 20:03:49

No not always, because if you fit say 17 inch you will probablyy fit a lower profile tite to gain the advantage of performance and handling, thats why newer manufactures are doing that now, so the lower profiles with bigger 17inch should end up the same, its called rolling circumference.all tire manufatures have these specs.