Metric versus inches rating

[nick112207]

What is the difference exactly? in the exact same brand you can get a 315/75R17 or a 35x12.5R17, and as i understand it they are ALMOST the exact same size. Yet people will tell you oh no you can't run a 35 you have to run a 315? why is that? maybe i'm missing something?

[cumminshakesit]

check out this site, it should break it down a little... i have trouble with all that metric stuff too. good luck. 315/75/17 = 35.6x12.4/17 you should be able to run either on a 17 with a leveling kit??

Metric Tire Conversion Calculator - Red Rock 4x4

if this link doesn't work just google tire conversion and click on the first one. lates

[kenny110482]

ive got 35x12.5 on mine all stock. Only a touch of rup at full lock to the left.

[nick112207]

yeah i never understood it haha. though i did find a site that would compare two different sizes and the numbers came out to be the 315 was a little taller at 35.60" where as the 35x12.5 was a little wider at like 12.51" versus the 315's 12.40

[kenny110482]

Yeah i dont understand it either. Why cant we just use one standard way.

[nick112207]

because then the tire companies wouldn't be able to make as much money? haha idk really

[strick69]

The first number is the width. Second number is the height of the sidewall based on a percentage of width. They are in mm

Take the first number mutiply it by the second number as a percentage. Divide by 25.4 then double it and add the rim size.

315 * .75 = 236.25
236.25 / 25.4 = 9.3
9.3 * 2 = 18.6
18.6 + 17 = 35.6 -------This is the height of the tire in inches

to get the width take the first number and divide by 25.4

315 / 25.4 = 12.4----------the width in inches

No you know, and knowing is half the battle.