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Roll Tide!
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Discussion Starter · #1 ·
I need someone to explain truck tire sizing to me. I can't seem to get it from looking on the internet.

I need to replace some LT275/70/R18's on my F350. I would like to get something a bit wider, but do not want to change the overall diameter of the tire. What sizes should I be looking at?

Also, does anyone have any suggestions? I want an AT tire that gives a good balance grip in mud and sand but is still quiet and smooth on the highway.
 

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i have 315/75/r16 on my f250 but i think it works like this

275= hights 70=width r=rims size
my 75's are wider and i know you can get them in a 275.
i have the goodyear wrangler mtr and they have been the best tire i have owned but they are about $250 per or something along those lines
 

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I went with the Bridgestone Dueler "Revo". awesome in mud, wet pavement and almost no noise.
 

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first number is the tread width - with more tread on the road, expect to loose a bit of fuel efficiency

Dueler AT Revo's are good tires. Keep them rotated regularly, as cupping was a problem when I bought a set several years ago on my last truck.
 

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If you go to disount tire's website, their system will tell you what sizes you could go to without changing wheels.
 

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Boatright custom flats
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275 = WIDTH

70 = SIDEWALL HEIGHT

18 = WHEEL DIAMETER

If you've got a 275/70/18 and want to go wider, you'll need to look for like a 285 or possibly a 315. But remember this, the sidewall height is in direct relation to the width. For example, the 70 (correct me if I'm wrong), is 70% of the tire's WIDTH. So, a 315/70 is going to have a taller sidewall than a 275/70. Have I totally confused you yet?????
 

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so tell me then if i went from a 305 to a 315 and everything else stayed the same on my tire after i lifted my truck why was my tires taller?
my understanding is a 305 is roughly a 33" tire and a 315 is a 35" tire
 

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Boatright custom flats
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Like I said above, the 70 describes the sidewall height as a percentage. A 285/70 tire's sidewall, is 70% as tall as the TREAD is wide. A 315/70's sidewall is 70% as tall as the TREAD is wide. Same percentage, but wider tire equals taller sidewall.
 

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Boatright custom flats
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To make it even clearer, look at a low profile tire, like a 225/40/15. The 40 has an extremely low profile sidewall. A 225/75/15 would have a very tall sidewall, resulting in a taller tire.

I agree w/Speckle on the brand. I had a set of Dueler Revo's on a Z71. I did a bunch of research before I bought them, and they had the best reviews for on and off-road performance. Bought mine at Firestone. They WILL match prices if you find them cheaper on the net too!
 

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You must have a King Ranch. The 18 inch wheels limit your AT choices. I couldn't stand my Contis. I ended up putting a 2.5 inch leveling kit on my truck and Toyo 325/65/18s.
 

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Roll Tide!
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Discussion Starter · #13 ·
Thanks for clearing this up for me guys! :spineyes: I think I'll just go buy a Civic!

Yes I do have a KR and have finally worn out those **** Conti's that came on it. I was hoping to get something decent to put on it without buying new rims or raising the ride height. It goes in the parking garage at work with 1" to spare and I don't want to park at the surface lot two blocks away.

LAt22, what is the diamter of those Toyos compared to the Conti's?
 

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tires

As to which tire to pick I would not go with the Nitto Terra Grapple;r poor mileage and I have been stuck in sand and mud both due to poor tread! I think the best all-terrain tire that I have used and witnessed is the B. F. Goodrich All Terrain! The Mud terrain they make is also exceptional off-road and very mild mannered on-road; with a very good tread life! But its all buyer opinion!

Chad
 

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I have the BFG at/ko 285/75/18 on my dodge. it is like a 33 or something close. maybe 32"

I have used these tires on the last two trucks I have had with great results. I really like them. If you didnt know I have a 3/4 ton diesel that gets used.....40k in 14 months.
 

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Roll Tide!
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Discussion Starter · #19 ·
Argo,

My current tires are 32" so that might be a good choice. Thanks for posting and nice rig.
 

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Tire size

The exact way to convert
275 width in milimeters 275/25.4 = 10.82 width in inches
70 percent of the width that the side wall of the tire is equal to (distance from the edge of the rim to the tread) 257*.70 = 192.5mm or 7.58 inches
Now to determine the total hight of the tire you add the side wall hight (twice because from the ground up you have rubber rim rubber) plus the rim height 7.58+7.58+18 = 33.16

So the size of your tires are 33.16 tall and 10.82 wide. When you chane only the first number both sizes change because the second is a percentage of the first.

To make it worse some companies measure a little on the bigger side while some measure a little on the smaller side. Also a block tread will always looke wider than a rounded tread.

As to what you should run a your SD. Nitto Terra Grappler and Toyo Open Country ALL TA are almost identical. Both make a good number of tires in 18, and most (unlike other companies) are load range E. A 325 60 18 will clear stock and be quite a bit wider but not any taller, a 325 65 18 will be a littler taller and wider than stock, but without a replacement bumper you will need a leveling kit. BFG has recently come out with some additionas to the 18 inch rim market, but I am not surer the exact sizes. I think they have some in between the sock and the Nitto/Toyo like a 285 60 18, 285 65 18, 305 65 18 and a 35 12.50 18 in the All TA tread.

I run 35 12.50 18 BFG muds on my SD, and would like to switch to 35 12.50 18 Toyo MTs but dont want to pay what they cost. If I was going to run an all terain I would run the 325 65 18 Nittos, they are easier to find then the Toyos and a little cheaper. I do however have a leveling kit.

Hope this helps.
 
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