I understand the 285 or so in the beginning is the width, and the following number is the length of the sidewall but how do I know what size is about a 35?

I want to get of Duratracs as close to 35 as possible and run KMC Monster's 17x9. So what exact size would I want.

I'm putting a 1.5 Teraflex Performance Leveling Kit or a 2' OME Lift with Bushwacker flared fenders to fit them.

 

Go out to Goodyears website and look up that tire. There will be a full specs list for every single size, giving both the metric and standard height/width.

Then do some searching to find the actual mounted height of the tire you want. You will find that it is probably an inch or so smaller than listed.

If you want a 'true' 35", you will generally be looking at 36-37" tires.

 

To do it on a calculator I follow this method. Take the width (285) and multiply it by the ratio (example: if 70 then multiply 285 by 0.70 giving you 199.5). That is the height of the sidewall in mm. Since you want it in inches, divide it by 25.4 yielding 7.85, which is the height of the sidewall in inches. Since there is a sidewall on either side of the rims diameter you have to add two of them to the rim diameter for the tire diameter (in the case of a 285/70R17 you'd add 7.85x2 (or 15.7) to 17 to yield 32.7" diameter tire. For the width in inches simply take the metric with (285) and divide it by 25.4, which gives you 11.22. Thus a 285/70R17 tire would be equal to a 32.7 x 11.2 (or rounding a 33x11) tire.

So, to get close to a 35 in a duratrac, you'll want a 315/70R17 (34.4 x 12.4) or a 325/70R17 (34.9 x 12.8).

Good luck!

 

Hookem, you a match teacher? Geeez. Thanks for the info. I did google it but didn't find a calculator. I'll double check.

Now as long as they say they fit a 17 inch tire, I should be good with a 17x9 right?