I got into an argument with a buddy of mine, over what the numbers mean in tire sizes. I'm not going to tell what either of us said, that way I can show him this thread and prove I was right!!!

So if you fine people could help me out that would be great. Please break down what these numbers mean in relationship to the tire.

285/75/16

I will say that we both agreed on the 16 being the size of the wheel, he isnt that stupid!!!!

 

285 = width of tire in mm
75 = aspect ratio (a percentage of the tire's width) determines height of the sidewall
16 = rim size

 

285 is the tread width in mm. 75 is the sidewall ratio. The sidewall is 75% of the tread width. (285 * X = .75) and 16 is your rim size.

 

Thank you guys very much. I was right, and I knew it! I just sent him the link to this thread in an email, so I cant wait to here what he has to say. Some people just cant admit when they are wrong!

 

Quick and simple...

As mentioned above 285 would be the cross section in MM's in inches it would be 11.22" (divide MM by 25.41) and the 70% thing would be 285 or 11.22 times .7 = 199.5MM or 7.85" for the sidewall height.

In theory if this were a 285/70R16 it would be roughly 11.25" wide and 31.7" tall...

sidewall height X 2 + rim size = height of tire.

All of this is sloppy math though because tires don't blow up perfectly square and/or are mfg'd with different lug patterns or shape profiles and the width of the rim it gets mounted on makes a difference in profile too.

Hope that helps.

 

That was perfect! My buddy is pissed to find out that he was wrong, and I love it!! Thanks again guys!