Dumb, Newbie question

Rockaround said Ok, some of you will probably get a chuckle out of this.

I have a Jeep Wrangler Rubicon with Falken Wildpeak M/T LT285/70R17 tires.  What I'd like to know (and can't find ANYWHERE) is what size they are.  31"? etc.  Is that just a measurement that you measure with a tape measure?  I've been to the manufacturers website and can't find that info anywhere.

Thanks for the response.

Hi there. Welcome!

Check out the tire size calculator at https://tiresize.com/calculator/.

Input the info you have and it’ll give you the info you’re looking for. When you do you should find that your 285 is a 32.7 inch tire.

What is funny is how they came up with the code.

LT is the type of tire ie LT Light Truck, P Passenger

285 is the width in millimeters from sidewall to sidewall

70 is the aspect ratio of ground to rim height of tire to width.

R is for the construction of the tire R Radial B Bias Ply

17 is the rim size

So to find the actual tire height you need to find out the tire height to the rim and double it, convert it to inches then add the rim size

(2 * (285 * .70))/25.4 + 17  = 32.7ish

Who said you wouldn't use algebra after high school. Only an engineer with too much time on his hands would use metric, inches and percentages in the code.

Luckily when you get larger tires most manufacturers know we aren't that smart so they put the rough size right on the tire. 🙂

google:  Tire size calculator.  Pops right up.

Thanks - Good info

The aspect ratio is a percentage of the width. 285 x .70 = 199.5 ÷ 25.4 = 7.85 x 2 = 15.7 + 17 = 32.7

25.4 mm = 1"

Knowing the formula you can find the size of a tire.

285 mm = 11.22"

So basically it's a 33 x 11.5

70dustpan said The aspect ratio is a percentage of the width. 285 x .70 = 199.5 ÷ 25.4 = 7.85 x 2 = 15.7 + 17 = 32.7

25.4 mm = 1"

Knowing the formula you can find the size of a tire.

285 mm = 11.22"

So basically it's a 33 x 11.5

WOW