nolagtime

This go-round I would like to go to a larger tire, not necessarily wider but taller.

Stock size is 275/65/18.

What is the largest P-Rated tire available? I do not want or need the added capacity from an LT tire. I will consider 17, 18, and 20" rim sizes.

Reason for the P-rated request is is 99% of my miles are empty highway miles and I do not need a heavier tire robbing me of my mpg. Not sure what the formula is, but added weight in wheels/tires is worse on economy than adding payload weight.

Any constructive input is appreciated. Thanks.

Craddosk

I've been thinking of this, with the same stock tire size, but going with the skinniest, tallest tire possible.

In for interest on size. My choices will be in an E-rated LT tire though.

nolagtime

For my needs I don't want E rated, as that is 10 steel plies of weight added to the tires rotating mass, adding weight and load carrying capacity that I do not need. I just want bigger, not heavier... if at all possible.

FX4ord

The tallest available? How tall is tall?

P rated BFG KM2s go as big as 40x14.50.

The tallest that will fit on a stock 4WD F150 is probably 285/75 R18 or equivalent.

For example, Toyo OC MT P285/75 R18 is 35.1" DIA; 11.6" wide; 70.6 lbs; E/10.

That's light for a 35" mudder. Not all E/10s are necessarily heavy.

BFG KM2 P-rated come 36", 37", 39" but get wider and heavier quickly as you go up.

There are taller lighter Q rated models that are better choices, IMO, with the higher speed rating. See BFG KM2 37x12.50 series, all close to 70 lbs.

g4b0r

Tires get heavier as you go up in size even if you don't go to an LT tire. I decided to get a set of LT tires, and I went up just one size from stock. I can confirm that adding rotating mass hurts the MPG.

I went with 275/70/R18 Terra Grapplers. These are 33.2 inches in diameter. I don't know how big you can go, but I do know that this size will not rub anywhere. You will notice a small drop in acceleration and a drop in MPG.

I think it fills up the wheel wells nicely:


I'm happy with the ride, and highway tire noise. My wife didn't even notice the tires changed at all. While it's only 1 inch larger than stock, I think it looks way better. If you're worried about MPG I wouldn't go larger than 275/70/R18.

Well, I'm not sure I helped you any...

Craddosk

Those look good. Any clue how skinny a tire you could put on the stock rim without risking losing the bead?

BLU4TJW

Looking at P rated, you are somewhat limited. And seeing as most of your described miles are strictly highway, and you're concern of unnecessary weight, makes for even less availability.

That said, many manufactures offer P265/70/18 which measures 32.6" vs. 18" stock 32.1.

P275/65/20 are also available from several manufactures including the Michelin LTX MS2. They are 33" in diameter and would look good and suit your needs as specifically stated.

I'm in almost the same boat. I am looking for a 33" replacement, but am torn because my needs are in between that of the quiet, comfortable P series vs. the towing capacity, and more sizing options of the LT tires available.

Michelin offers the the LTX MS2's in the LT 275/70/18, and that's the tire I am leaning to, as I believe it will offer the nicest ride, best mileage, will tow my boat and trailer easily, and is the tallest tire I can justify.

LueyC

OP,
I understand where you are coming from. My truck came stock with P275/65 18. I upgraded to LT275/70 18. Here is a pic(no level, no rubbing):


Observations: I like the way the P rated tires drove on road. I may have to play with air pressure on my current tires I think it is a bit high @50 psi and I am feeling alot of bumps on the (crummy) roads. I like the way the the truck looks with 33's. MPGs may have dropped by .3 - .5 MPG, I have not tested it yet during the summer, so I cannot say for sure. I had seen similar trucks(CC 6.5') with 34's and a level and think it looks awesome. So I have to decide which way I want to go with it LT 34's (295/70 18 or 275/65 20) with a level or P 33's (275/60 20). I am also toying with the idea of taking the running boards and bed steps off and seeing how it looks. If I like it I may wind up going with the AMP automatic running boards. If I get rims I will try to get OEM 20s or after market 20x9 30-35 offset. I love the stance on the Harley F-150's (Tire right to the body, not sticking out) and if I go P rated that is what I would try to replicate. What looks good on shorter trucks doesn't always look as good on the Crew Cab 6.5' bed trucks.

I am leaning towards the 34" with level, but I will wait until I see what it looks like without running boards. If anyone wants to ship wheel and tire combos to me I will drive around on it for a week, take pictures and provide a review , ha ha.

smokeywren

To get taller without getting wider, you must increase that middle number from 65 to 70. To get narrower but not taller, decrease the first number from 275 to 265.

There is even a size P255/70R18. It's narrower and lighter, but has the same diameter as your stock tires.

So to get taller and narrower, then you want size P265/70R18.

Recommended size in red:
Size............section width..diameter.. weight .. capacity .. revs/mile
P275/65R18..... 11.0" ........ 32.1" .... 40 lb ..... 2601 lb ... 648
P265/70R18 .... 10.7" ........ 32.6" .... 43 lb ..... 2601 lb ... 637
P255/70R18 .... 10.2" ........ 32.1" .... 38 lb ..... 2469 lb ... 648
LT275/70R18E . 11.0" .........33.2" .... 53 lb ..... 3640 lb ...627

It would be nice if someone made a 255/75R18 tire. That would be taller and narrower than any of the above. But nobody mades it that I can find.


You're right that an E-rated tire will be heavier than a passenger car tire of the same size. But not because of the number of plies.

E-rated tires have a "10-ply rating", but most are only 2 sidewall plies and maybe two additional tread plies. The actual 10-ply tires of 70 years ago had 10 plies (layers) of cotton string covered by a thin layer of rubber..But nylon cord came along in the 1940s, and then the words changed to 10 ply rating, because it required a lot fewer plies of the stronger nylon cord to carry the same weight as the cotton string. Because customers understood the number of plies, the industry changed the words to ply rating. Later the nylon cord was replaced by even stronger polyester cord, and later still by radial construction replacing bias ply. Steel cords are only in the most expensive light-truck tires, such as the Michelin XPS, but there are only two steel plies in the sidewall of most "all steel" tires , and three at the most. So that's why a modern tire with a 10-ply rating has only tow plies in the sidewall.

nolagtime

I was considering a 6" lift... will research what tire in a 35" is lightest weight. Any recommendations for a good AT highway tire? Thanks for the feedback.