I have a 07' F150 XLT 2wd. Im getting ready to put on my AS 2.5 level but im waiting untill i get some 265/70R17 tires. Stock size is P235/70R17 btw. How big of a deal is it if I bought a set of P series tires like the stock ones versus a set of LT tires? I was told i should get light truck tires (makes since) but i mean it came with passenger car tires on it..?? any help appreciated! thanks

Also probably going to get either Terra Grapplers or BFG All Terrains.

 

Unless you are towing heavy loads you should be fine with P rated. LT are a heavier (and usually more $$) tire designed for increased weight / workloads.

 

U will be fine! I put P265/70R17 Nexen Roadian ATII on mine and love them. No problems with weight or clearance, and I don't have a leveling kit.

 

I would go with the LT's if I were you. If the P rated tires worked for you then stay with them. On my last set of tires I went from a LT to a P and I will never do it again. The P are a 5 ply and an LT is a 6 ply tire. If you like to drive above the speed limit a little and like better cornering go with the LT's. They are a little bit stiffer and help hold the weight of the truck better when taking hard turns like on/exit ramps

 

Yeah LT's will be stiffer but also heavier, they can be 8 ply or 10 ply aswell. They will feel like they corner better due to their being more rigid therefore more responsive. P tires will be softer, more cushiony and have more sidewall rollout. Most P tires our trucks come with are rated for approx 2500 lbs and our trucks payloads are maxed out around 1500 lbs so really they're good enough, it's all just preference.

 

Payload has nothing to do with it. It has to do with the GAWR or Gross Axle Weight Rating. On our trucks that is about 4,000lbs for the rear, slightly lower for the front, give or take a bit depending upon GVWR. That 2500lbs is not 2500lbs when used on a light truck. That figure must be reduced by at least 9%, or about to 2255bs. That is why, the recommended pressure for P rated tires is the max, 35 or 44 depending upon the tire. Never use a P rated tire that doesn't have at least a weight rating of about 2300lbs before subtracting the 9%.
An LT tire will handle the weight much better than a P, it will handle better in the turns, and it will last longer in harsh conditions where a P will end up flat. This all assumes that the tire is run at the correct pressures.
A P series will have a softer ride, give slightly better fuel economy, and be cheaper to purchase.
Note, all the 8200lbs GVWR trucks come with either LR d or E LT tires.

 

Hey King, speaking of pressure, If he moves from a factory 275/65/18 tire and moves into a larger lt tire, say lt295/70/18, or even lt35x12.5x18, would he change the tire pressure he runs at? And perhaps in short form, why?

 

Unfortunately, the answer is it depends. Depends on load range and max pressure. I can point you to tires that are a p series that have max pressures of 35, 44, or 50. An LT LR D with max of 50 or 65, or a LR E with a max of 65 or 80. Each of these tires might require a different pressure, and they could be the same or different sizes. In general, the size of the tire makes no difference on pressure.

 

So lets assume for a moment that ford recomends 33 psi on the door jamb on a '10 f150. (I'm too lazy to go look at the exact #). Are you saying that they make that recomendation based on the specific tire they chose for that model? And if you change tires to say the nitto trail grappler 35/12.5/18lt, that you would have to ignore the door jamb tire pressure and go with the recomended pressure from nitto? Where would you even find a recomended pressure from the manufacturer? They only print the max tire pressures on tires, not recomended. Max, and recomended are not the same......

 

Yes, it is for that specific tire. You will find different recommended pressures on the sticker depending upon which tire came with the vehicle. As an example, mine came with a LR C LT tire. Recommended pressure is 45. Yes if you change tires you should ignore the door sticker unless, it is the same LR, weight carrying ability, and max pressure.
Unfortunately, there is nowhere to go to get what you should use. I have heard of tire dealers that say just use what is on the door for a LR E tire with a max pressure of 80, when the door sticker was for a P series with a max of 35. 35 is way too low for a LR E with that max. At best, a LR E, which has a very high weight rating, 40 would be the minimum, and then only for an unloaded vehicle. A LR E will normally have a weight rating from 3200 to 4000lbs. At 35, the tire cannot handle half of that value, and could be dangerous on the highway. You just have to use some common sense and look at the numbers.

Some other place to look at is the rule NHTSA created for the use of the Tire Pressure Monitoring Systems.
Scroll down about 1/4 of the way on this. It has a chart of pressures. Even though 46 is listed as the minimum for a LR E, some tires have a much higher rating, so that when used on an F150, lower than 46 could be okay, but anything lower than 40 could be a problem.

http://www.nhtsa.gov/cars/rules/ruli...e.html?name=#B

 

Stick with the P rated tires. The LT tires will ride to rough.

 

OK, but what would you recomend to those of us who want to install levelling or even lift kits, and want either 35, or close to 35" agressive tires? What "P" options are available to us?

 

Not trying to revive an old thread but thought I would share this information regarding tire pressure. If you have any questions about what tire pressure you should run your tires contact the tire manufacturer and they should give you the tire pressure specific to your size and vehicle configuration. I contacted BFG and they were very helpful. I also contacted Goodyear and they would not provide me with any info and told me to contact the vehicle manufacturer.