Im thinking of swapping out my 16" Touring cups up front for some 15" racing wheelz. I need to know what size tire on a 15 will match the overall diameter of my 205/45/16s in the rear.
16" +205/45-16 = 400 + 92.25 mm = 492.25 mm diameter
15" + 205/50/15 = 375 + 102.5 mm = 477.5 mm diameter
15" + 205/55/15 = 375 + 112.75 mm = 487.75 mm diameter
- 1" = 2.5 cm (25mm)
… think i did that right …
search for the “miata tire size calculator”
you will find the web page easily. It will answer all your questions and give you speed difference ratios too.
Remember to compare to the original tire size (14" 195/65)
Good luck.
stock size is 195/60-14
plus one is 205/50-15
plus two is 205/45-16
plus three is 205/40-17