03 F-150 2WD Screw with a 3" body lift. Just put LT285/70-17 BFG Rugged Terrain's on it. What air pressure would you guys rec for the best gas milage? I don't really do any off roading but do have to drive through a field on a regular basis. The guy at the shop told me to run 40PSI for the best traction but they hold up to 80!

 

Several posts on this subject already. Try here as well:
http://www.4wheelparts.com/tire-whee...e-checker.aspx

I doubt you are going to get any "noticeable" difference in gas mileage.

 

There is some good info there, but there is also some stupid info there. Saying to use the max pressure is idiotic, especially when talking about a LR E with a max of 80 psi on an F150. The only thing that will do is cause excessive tire wear and possible an accident with so little tread actually on the road. Too little pressure can be as bad or worse.

To the OP, that tire has a max load of 3195 at 80 psi. At 40, that does not carry more than half at beast, which is too low. You want to get at least 2000lbs per tire for an F150. I would use at minimum, 45, and then only empty. Personally I would use 50. If you tow heavy, or carry a heavy load (near max GVWR), I would use a few more psi until done.

 

Why did you get LR E tires? LR C or even D would be overkill..

Anyway, run what feels comfortable to YOU.. MPG's are not going to be had one way or the other. Those LR E's probably weigh #10 more per tire than C's would, so that's gonna kill any gains right there..

40 does sound about right. I run 40 in the rear and 44 up front with my LT 265/75/16 tires for everyday driving. Towing, I pump them up to around 48 psi all around.

Just "feels" right to me. I usually get 60k miles out of a set of tires and that's replacing them long before they get to the wear markers.. I hate running on less than 40% tread, but that's just me..

Good luck!

Mitch

 

And I can tell you now, your Wildcats are not a LR E. It is dangerous to run any tire too low. Your LR C tires are properly inflated at the pressures you stated. A LR E tire would be well under inflated. The rules made that for the tire pressure monitor systems requires that the system warns when inflation of a LR E tire with a max of 80 hits 46 psi. While most LR E tires come on heavier vehicles than the F150 (although the 8200lb F150 does have them) does give a little leeway, going too far down is definitely a problem. At 40 psi, that LR E tire does not even have 1600lb of load carrying ability. Double that, 3200lb, is way below the GAWR of a regular F150. Also the recommended pressure for those F150s that come with LR E tires is 50 psi. Only the LR C tires are recommended for 40 - 45 psi.

As to why a LR E, that size tire only comes in a LR E from BFG.

 

Vast majority of larger tires are E rated. I remember someone in one of the many posts I looked at on the subject had a set of Nitto's and Nitto told him 42.5. That is what I have been running mine at.

 

That might be right, for the Nitto. Some of the Nittos I have seen have a very high load rating, 4000lbs at max pressure. For them, the 42.5 would be right, but not for the BFGs.

 

Call BFG customer service. They will tell you what is right/recommended for what you have.

BFGOODRICH CUSTOMER SERVICE

1-877-788-8899
8 a.m. to 8 p.m. (M-F)
8:30 a.m. to 4:30 p.m. (Sat.)
(Eastern Time)

 

My tires are LR C.

In general, running a LR E tire at a lower PSI WILL lower it's max load rating, but give you a better contact patch when not at MAX load cap. No need to run 80 psi when running empty, is there?

You do have to find what the different load ratings are for a particular LR of course and know what the actual load you are placing on the tire is too..

Was not aware that BFG only sell (LR E) in that size, well, there you go!

Mitch

 

Never did say to use max. That was what was said at that site, which is stupid. My recommendation was 50, a pressure I have used on BFG ATs before with good success. Also the pressure Ford recommends for LR E tires they use that have very similar numbers.

PS - When you look at many tire sites and specs you will find that in many cases tires are only made in one specific LR, quite often LR D or E. Even more than LR C.

 

This probably the best bet. Out of curiousity I called Nitto about my Crosstek HD's. They recommended 41 psi.

 

Wweeeeeelllll the Rugged Terrains actually come in a P-metric or an LT version in the 285/70-17, I ordered the P-metrics on June 30 but apparently BFG is having a recall on almost a million commercial tires and as of last week the P-metrics still had no arrival date in sight. I've been driving on bald as hell tires and couldn't wait any longer so basically had no choice but to get the LT's even though it cost me another $250. They're only about 5 pounds heavier per tire so hopefully the gas mileage hit wont be too bad.

I rarely carry anything heavier than a sofa or old TV in my truck so load isn't a problem, and I tow a trailer maybe once a year at most. Thanks for the info guys I think I will go ahead an call BFG customer service!

 

I finally took the advice here to call the manufacturer for my tires. The rep told me to use whatever the placard on the door said. I mentioned that that was for the original tires and she replied that it didn't matter. She mentioned the "center wear" issue if I went any higher than that.

Cooper Discoverer H/T LT265/75R16
DOT UTW8 1BE
Load Range E (that's what Discount Tire had)
123/120Q
Max Load 3415 @ 80psi

When I bought the tires, they put in 45psi. I lowered them back down to 35 (placard says 32/35). Lately I've been getting some vibration up front (less than 2000 miles on tires) that I could feel in the steering wheel. New shocks/UCA's/lower balljoints/tie rod ends and alignment. I bumped the pressure back up to 40psi, and the vibration seemed to diminish.

I know it's a truck and my perception could be a factor here. I don't expect it to ride like a Caddy. I don't haul anything or carry any significant loads often. Any help on the optimal pressure to run?

Thanks!

 

Even that 40 is a bit low. You would do better at a minimum of 45. I would not be surprised if that vibration is due to damage to the tires due to low pressure. That 35 was way too low for a LR E tire with a max of 80. What was stated by the Cooper rep is just plain stupid.
Each tire put on by the vehicle manufacturer will get a different recommended pressure. Ford has at least 4 different recommended pressures depending upon the tire.

 

"Cooper rep is just plain stupid" I agree, call back, maybe you'll get a more knowledgeable rep.