Jeep Wrangler Forum - Reply to Topic
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > General Jeep Discussions > Tires & Wheels > New wheels but so lost in terminology

Join Wrangler Forum Today

Thread: New wheels but so lost in terminology Reply to Thread
Post Icons
You may choose an icon for your message from the following list:

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Additional Options
Miscellaneous Options

Topic Review (Newest First)
06-08-2013 07:51 PM
Willshire Yes it does thanks just trying to understand it all and how to get the look I want.
06-08-2013 11:17 AM
dawhitesJKU ^Close. lol. thats what i thought before until i educated myself.

To help you understand tire sizes, let me give you my example
My toyo at2 is 285/70/17.


1- This is the width of the tire in millimeters. The conversion is 1"= 25.4mm so for our example: 285/25.4= 11.22" width.

2 - This part is the "aspect ratio" of the tire and is a relation of the tire's width to the sidewall height of the tire. My example is '70'. This means the sidewall height is 70% (.70 in calculation) of the width of the tire. (this part of the math i don't know lol)

^edit: 11.22 x .70= 7.85

3 - Your wheel size. (i say wheels...since rims are on motorcycles...its like when people say headers when theres only pet peeve)

In conclusion, a 285/70/17 equates to 11.22 wide and is (7.85x2)+17"= 32.71" tall, or basically equivalent to a 33x11.50R17 if we can call it a standard size.

BUT.....the real measurement takes place once the tire is on the wheel and set to psi. then you could use a measuring tape. mine came up to 32 tall, and a lil over 11 wide taking real measurements for my procal setting.

i hope this helps.
06-08-2013 10:47 AM
Marmotte729 Hi,

I’m thinking of getting new rims and tires too. I agree, this is confusing. I have learned that in 255/75R17:

225 is the width of the tire thread in millimeters

75 is the height of the tire in % of width. So your tire from rim to thread is .75*225=169 millimeters.

R means radial tire

17 is the diameter of your rim in inches.

In my case, I have 16 inch steel rims now and would like to stick with 16 inch rims but can’t figure out how to tell which alloy rims fit on the Jeep. I’m told some would hit the calipers so going to a 17 inch rim is safer, not my preference.

05-29-2013 08:50 AM
mdelguidice No expert here, but maybe I can give a little help. The 255 is your tires circumference, the 75 has to with the height of your sidewalls and the 17 is your wheel size. The larger the first number the larger the tire. Discount tire direct has a pretty good tool to help visualize this. Do a search for Discount tire direct tire calculator.

Hope this helped a bit.

05-28-2013 11:15 PM
New wheels but so lost in terminology

Looking to purchase new wheel for my 2009 jk and would like to stick close to stock size maybe go up in tire size down the road. But i have no idea what the back spacing means or what size the stock rims are. All I know is that the tire size is 255/75/r17 thats all i know cause i read it off the door. Kinda of new to all the wheel stuff but love the look of the tire coming outside the fenders some.

If I buy new wheels do i need new tire pressure monitoring system or can I take the old ones from factory rims. Would want black rims. Have no idea which brand is good or bad like I said pretty new to the whole changing the rims over.

Right now I'm running firestone international a/t and there ok tire want something little more aggressive for the next time. Have to kill these tires off before I buy new again

Any help would be greatly appreciated

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -5. The time now is 01:57 PM.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC. is not in any way associated with the Chrysler Motors LLC