tire size calculator??

[Mindstatic Pro]

My wheels are 19x8.5 up front and 19x9.5 out back. I have 245/35's up front and they look great with the car being lowered. I had 275/30's out back and their overall diameter ended up being just a hare smaller than the fronts. Not super noticeable but an eyesore to me none the less. Im not putting the wheels back on until I get the right size for the rears.
Ive been considering 285/30's, or 285/35's and would like to know the overall diameter of my wheels with these tire sizes before ordering the new ones. I know there is a formula for this but all my googleing hasnt brought up the correct calculators.
I would like the rear overall diameter to be a little bit bigger than the fronts to fill the gap between the tire and fender. Anyone have some suggestions???

 

[Tonys96Cobra]

http://www.miata.net/garage/tirecalcold.html
link updated

 

[Mindstatic Pro]

That link is dead. I meant to add that I wanted a calculator or formula that included the wheel width. All that I have found only have input for tire size ie. 285/35/19... the width of the wheel will also have an effect on the overall diameter.... 285/35/19 on 8.5 in wheel would be a little different than on a 9.5 inch wheel.

 

[Die-Laughing]

These should help...

http://www.1010tires.com/WheelOffsetCalculator.asp

http://www.wheelsmaster.com/rt_specs.jsp

 

[Tonys96Cobra]

That link is dead. I meant to add that I wanted a calculator or formula that included the wheel width. All that I have found only have input for tire size ie. 285/35/19... the width of the wheel will also have an effect on the overall diameter.... 285/35/19 on 8.5 in wheel would be a little different than on a 9.5 inch wheel.

I dont think wheel width is going to affect your diameter enough to matter. Not even 1/10th of inch. I updated the link for you.

 

[jeffnoel]

I haven't seen a calculator that takes width into the equation.

 

[Die-Laughing]

http://www.wheelsmaster.com/rt_specs.jsp

Exactly what you want to know is right there!

Here's the specs i put in to compare the two sizes your dealing with:

245/35/19x8.5 (front) overall height = 25.8" (655mm)

275/30/19x9.5 (rear) overall height = 25.6" (649mm)

if you use rear tire size:

285/30/19 the overall height will be 25.8" (655mm) which will match your current overall height in the front.

285/35/19 the overall height will be 26.9" (683mm) which will make the rear a higher overall height than the front.

It's that easy, check it out.

jeffnoel-"I haven't seen a calculator that takes width into the equation."

I dont get it.

 

[jeffnoel]

I was referring to rim width which is what he asked about in post #3 if you read the whole thread . And I checked your linked calculator and used the same tire size on 2 different rim widths, it made no difference in overall tire height.

 

[iskwezm]

rim width will not affect tire height at all.wheather or not the sideall is stretched or not will change the dimension

take a 275/40/17 tire for example
275/ 25.4 = 10.8" in width
10.8X.40(aspect ratio)=4.33" in sidewall
4.33X2(2 sidewalls)=8.66" total sidewall heights
8.66+17(tire size)= 25.66" tire height