Tire Size?

[Conundrum]

My questions are, what size tires are stock on the 2wds? P235/75/15s or LT235/75/15s? And what is the diameter of the stock size tires?

I am going to need new tires for my daily soon, and I am looking at putting 20s on one of my project trucks and dont want to throw off the speedometers.

[LONGHAIR]

There is a difference between passenger tires (P-metric) and light truck tires (LT) but they can be interchanged if you follow the conversion chart. The sizes are close, but it usually takes more air pressure to use them on trucks.

As far as tire size (diameter), that is the beauty of the metric sizing.
All of the numbers have a meaning.
235/75/15 breaks down like this:
235, section width in millimeters
75, aspect ratio (height of tire from rim to ground expressed as a percentage of it's width)
15, wheel diameter (must be converted to millimeters)

So it works like this:
235mm x .75.........................176.25 (height of tire from rim to ground)
x2.......................................352.5 (tire is on both sides of the wheel LOL)
+ wheel diameter (in mm)........381
total is diameter of tire in mm..733.5
divide by 25.4 to convert to inches 28.87 (28 7/8")

[joe231]

good info longhair,
it amazes me how many car guys don't know how to figure diameter.....

[Conundrum]

Thanks for the info, that will help me out alot. I have never seen the formula for figuring out the diameter before. Though I did know what the numbers on the sidewall meant.

Part of the reason I was asking is that the light truck tires on one of my burbs appear to be much bigger than the passenger car tires on my dd burb, both being 235/75s.

[87Lowrider]

I saw his calculator on another thread last week.

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


Kenny

[piecesparts]

Use this simple calculator for tire sizes and comparisons. http://www.discounttire.com/dtcs/infoTireMath.dos


LASO:


this simple formula

235/75/15 tire calculated by 235 X .75 X 2 divided by 25.4 Plus the rim size 15" = 28.8" tire