TIRE SIZE QUESTION???

[OSOVTEC]

yeah...stupid question but its legit, i am buying 16 inch rims... i want the same tire diameter as the stock 15 si rims so i dont have to change the speedo and stuff whats the tire size, and how do i break down the numbers on the sidewall dammit

[5hift gear]

ex. 245/40/17

245 is width of tire
40 is the "profile" the length of tire from rim on the sides
17 is rim size


also here's a tire size calc. for you .. hope that helped.

http://www.miata.net/garage/tirecalc.html

[YourUserName]

What size tires do you have now?

Here is how to figure it out I will use the tires on my TypeS
205/55/R17

205/25.4 (mm in 1") = 8.07 SECTION WIDTH OF TIRE

8.07 X .55 (Aspect ratio) = 4.4385 HEIGHT OF SIDEWALL

4.4385 X 2(sidewall above and below rim) =8.87

16 (diameter of rim) + 8.87 (height of sidewall) = 24.87"

If I want to put 17" rims on I need to match the 24.87" or be really close.

So I take a 225/45/17 and I get

225/25.4 = 8.86 X .45 = 3.987 X 2 = 7.974 + 17 =24.974"

The difference is less than 1/8 of an inch.

[05 tC]

Originally posted by OSOVTEC
yeah...stupid question but its legit, i am buying 16 inch rims... i want the same tire diameter as the stock 15 si rims so i dont have to change the speedo and stuff whats the tire size, and how do i break down the numbers on the sidewall dammit

205/45/16 is the size you need. Your speedo will only read 0.8% to fast, nothing to worry about.

[CivicSiRacer]

The stock 1988-2000 Civic sizes are:

185/65x14"
195/55x15"
205/45x16"
205/40x17" (actually 205/35x17" but there is no such size)