I am running a set of 305/70/17 nitto terra grapplers and i was wondering what tire pressure should i keep them at for every day on-road use?

 

Those are a load range E with a max of 65. I would run them at 45. I would not try anything lower than about 42. 45 should be good for every day driving, even with a load on the truck.

 

load range E and max PSI is only 65 ? Strange. Aren't most E rated tires max PSI 80 ? I also have Load Range E tires. I usually run them around town at about 40 PSI. If i tow I up the PSI usually to about 60 - 65 and if I go off-roading I usually air down to about 25 psi or so.

 

Some of the newer ones are 65 psi max. Also if you are running an 80 psi LR E at 40, you are way too low. Run them at about 50 (if max psi 80). At 40 you are not even close to the rating of your axle. The 04 up are rated at 4000lb per axle. A LR E with a max of 80 run at 40 can only handle about 1500lb. Times 2 is 3000lb. 1000lb below your axle rating.

Also, if your vehicle was OE LR E tires, and had TPMS, it would be set to light the low pressure light at about 46 psi.

 

Thanks for the advice. interesting to know about the newer LR "E" tires. I have not yet seen that, but its interesting. My tires are fine at 40 psi. I like em like that and these are by far not my first E tires. Also, there is NO way our rear end, on the scale is 2,000 lbs on each tire. Can't be. My whole truck weighs what ? Just under 7k ? I find it hard to beleive more then half of my trucks weight is sitting over my rear axle (carrying an empty load) ? That would mean the bed and rear-end is heavier then the engine, tranny, front clip, cab seats and my fat ****. There is no weight back there. Maybe going up a hill ? There just can't be 4,000 lbs over my rear tires.

 

I am not saying your axle weight is 4k, but the axle is rated to 4k. With a load in the bed, you could have 4k on the rear. Front is probably between 3-4k at all times. Also, the 46psi is not from me, but from the feds.

Scroll down on this report. There is a chart with the PSI settings for the TPM system for each load range of tire.

http://www.nhtsa.dot.gov/cars/rules/...ule.html?name=

 

OOOOH, gotcha! Well I was talking doing an empty haul. No weight, just driving. and that is why i am VERY happy i do not have that TPMS. Like I said, these are FAR from my first set. E rated tires is just about the only thing I have run on my trucks. i usually stay right between the 40 and the 45 psi mark. And if I load up my bed, i fill up my tires. I will never pull or haul a load with 40-45 psi. I usually bump it up closer to 60-65.

 

I too have run LR E tires on an F150. I used 50 psi and got 40k+ off my tires. Don't know how long they lasted as they were on the truck when I traded it. But they still had some tread life on them.
The recommended pressure for the LR C tires that came on my 04 was 40, which if you calculate it out was for 2000lbs per tire or, 4k for the axle.

 

really interesting. Maybe I will try bumping it up a notch... but like I said, I usually fill it up to right between the 40 and 45 mark. Right around 42-43. You say you run yours at 50psi ? Sounds like the ride would be too rough ?

 

A little rougher, but it cornered better (less sidewall flex) and I did not have to worry about adding air if I carried anything.

 

FWIW, Ford's put C range LT tires on the F150, not E's.

 

No they put p series tires on with LR C as an option. I know it comes max with LR C, I was giving an example of what the TPMS would be set for if they came with LR E.
Also, a 8200lb GVW vehicle does have an option for LR D tires.