Tire sizes for CRX SI rims

[Rabies]

I have a base 91 CRX but just added some used stock rims from an SI (from a 1990 / though rims are stamped 1989?)

Anyways, turns out the tires they came with are too worn and I'll need to replace them. I'm a bit confused by the size I need because everywhere I look on the Web it says the CRX SI uses P185/60R14 but the tires currently on these rims are P195/60R14.

I understand that the 195's are considered going "plus zero". But is this a proper thing to do? My spedometor will be off, yes?

So what do I get as replacements?!

~RB

PS: In case it matters, this car originally had P175/70R13's on stock steel rims.

[CivicSpoon]

P185/60R14's would closest to stock.
Tire size calculator: http://www.miata.net/garage/tirecalc.html

[Hilikus Funkin]

it shouldnt affect your speedometer at all because 195 is the width not how tall the tire is

[CivicSpoon]

it will because the will be taller even by adding just a wider tire. The formula is Width(1st#) X % of Width vs Height of sidewall (2nd#) = the actual Diameter in millimeters. So a 185/60 tire would be 11,100 millimeter tall and the 195/60 would be 11,700 millimeters tall. So the 195 would infact be taller than the 185 tire by 600 millimeters. Unfortunately I don't know how to figure out the change from different rim sizes.

[TheSilentChamber]

eh, spoon your math is off buddy. its first number is width in mm second two numbers is an aspect ratio. like for say a 205/50 the sidewall is 102.5mm tall. rule of thumb, up a rim size, down 10 on the second number to compensate for the height of the rim.

[CivicSpoon]

Yeah you're right I am way off... I got to figure out where I went wrong...
Edit: Ok so the 185/60 is 111 millimeters and the 195/60 is 117 milimeters so those tire sizes are 6 milimeters off. So instead of me doing the 185 X 60 it's 185 X .60 (converting % to decimals). I still don't get the wheel size alteration though; still getting way off numbers. Oh well I'll stick with that calculator thing I guess

[Rabies]

Originally Posted by CivicSpoon

Yeah you're right I am way off... I got to figure out where I went wrong...
Edit: Ok so the 185/60 is 111 millimeters and the 195/60 is 117 milimeters so those tire sizes are 6 milimeters off. So instead of me doing the 185 X 60 it's 185 X .60 (converting % to decimals). I still don't get the wheel size alteration though; still getting way off numbers. Oh well I'll stick with that calculator thing I guess

That Miata.net tire calculator is pretty damn cool... and according to it I should have 185/60's not 195...

So that's what I'm getting! :-)


~RB

[papdetomaso]

185/60/14 first number 185 (width in MM) second number 60 is aspect ratio third number 14 is rim size. Take 185 and divide by 25.4 gives you width in inches (7.28) Take 7.28 and times by aspect ratio (60) gives you section height (4.37) or the distance from the rim to the top of the tire and the rim to the bottom of the tire. Take the section height times two (8.74) plus the rim size (14.00) gives you the total tire diameter in inches or (22.74) inches.