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New Rims and Tires, How Big are the Old Ones?

3K views 10 replies 7 participants last post by  kEat 
#1 ·
First and foremost: hey everyone, I'm a new Jeep owner as of September of this year. I bought my first 2002 TJ after longing for my dads 1997 TJ that he bought only months before; it rubbed off on me, :D.

Anyhow, onto my dilemma. I'm not used to measuring tires however they're measured in the Jeep/offroading world. 31", 33", 35", etc.? Is that the "height" of the tire? Because if it is, my stock tires seem to be 26", which sounds about right compared to the 31"s on my dads Jeep. Anyways, I can't afford a lift right now, but I need some bigger tires for the winter months (4WD means nothing with these stock tires, ugh). I found a nice set of 29" tires and rims that would supposedly fit my Jeep without a lift. Now this is not really what I'm concerned about, I just want to know how big they would be compared to my current tires. So could anyone tell me how to accurately measure my tires? Thanks!
 
#3 ·
Yeah the 30 9.50 is a stock size. I wouldn't think that you have a 26 in. tire, that would be really small. The 31, 33, 35 measurement is the standard measurement. A 31 10.50 is 31 inches tall and 10.5 inches wide. The other measurement, which you probably have if you don't have at least some 29's is metric. It will be stated as 265/75/15, or such. You can still figure out your standard tire height in inches by following this simple procedure. The first number is the tread width in inches. The second is called the aspect ratio. It means that each sidewall is that % of the tread width. All you have to do it take the first number(265) times the second as a decimal (.75) times 2, (for 2 sidewalls). Divide this by 25.4 (to convert to inches) and add in the very last number (which is your wheel size in inches.) For exampla a 265/75/15 would be - 265 * .75 = 198.75 * 2 = 397.5 / 25.4 = 15.64 + 15 = 30.64 overall tire height. To figure just the width, take the first number and just divide it by 25.4 so that tire would be 30.64 inches tall and 10.43 inches wide. Hope this helps!!
 
#4 ·
If your Jeep is stock, you can fit up to a 31" tire and have no issues. If your looking for the most performance, some 30-31" tires would be your best bet, but the tire tread is what will benefit you the most. A good all-terrain tire will last on the road and perform decently off-road on the trails.
 
#7 ·
Then thats what I have, mine definitely aren't 31". And actually, those are the numbers from my tires. I just wasn't sure if the other number came from the height (top to bottom) of the tire.

Anyways, I was talking to my dad earlier, and he said that when he first got his Jeep, they had 31"s on it with no lift and he had no problem with it, just some slight rubbing. So I'll probably go the same way and get 31" as well. These will probably only be temporary anyways, so thats why I want to avoid a lift for now. Come August of next year though, I'll be sitting on a cool 18 grand with nothing to blow it on but my TJ, :D. So THATS when I'll get into the big stuff. But for now I just need something to get by the winter months with, and maybe a bit longer.

Thanks for the help guys!

And Jherrin, thanks for the forumla, thats a huge help.
 
#6 ·
i'd go 31's dude, just kuz they're big and look tight with some agressive tread, or AT tread even. i have 30's x 9.5 and wish i had gotten the 31x10.5

BFGoodrich 31x10.5 All Terrain are good i thinks for roads and off roading
or i have Yokohama Geolander 30x9.5 and they're fine on roads and not bad off, just not as big as i want lol
 
#11 ·
Join the Air Force. :D

Bonuses up the wazoo. And then they'll give ya $1000 a month just to go to school, and pay for it too!

Go active duty and theres even bigger bonuses. Especially in the Army.
 
#10 ·
no problem, always try to help what little I can. It really helps when you start going with a different size wheel because it lets you figure out overall tire height. This is one thing that I have learned not very many people fully understand. I learned it when I was putting 17's on an altima I had and I thought it was useful enough to remember.
 
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