Quote:
Got some new info for you,
the Rs comes stock with 14" and a 70 series tire
A 17" rim with a 40 series tire is the exact same tire
A 18" rim with a 35 series tire is the exact same as both listed above
A 19" rim with a 30 series tire is the exact same as all listed above
|
That isn't exactly correct. There are three numbers in a tire size. The first number is how wide the tire is. This is an independent number, and is measered in mm (i think). A stock RS tire is 195 wide. But, you have a GS, and your stock width is 205. The stock tire on a GS is 205/55/16. The second number in the series is your sidewall profile. This is a DEPENDENT number, and is a ratio to the first number. Therefore, a 205/55 will have a shorter sidewall when compared to a 225/55. This is why the above info is incorrect. This is assuming that you keep the same width on the tire, which won't happen with 18s. The stock GS wheel is only 6 inches wide, where the 18 will be between 7 and 8. DO NOT GO WIDER THAN 8 INCHES ON THE WHEEL. Your optimum tire size for an 18x7 would be 225/35/18. Also, from what I have seen, the RS rolling diameter is smalled than the GS and above. For the RS at an 18, you would use a 215/30/18. The best way to do it is to find a rolling circumfrance calculator. I know one of the big Miata sites has one, but I don't remember the addy.