WVMoose

iTrader: (2)

Nitto said they recommend 45, not to go lower then 40, but recommended the chalk test. Ive been running mine at 44 based on chalk test, and that pressure is checked with my digital air press gage and it matches what the TPMS is reading.

Apples

Was your truck fitted with factory 20"s? If so, what was the Ford recommended Cold Inflation Pressure on the Tire And Loading Information placard on the door jamb. Humor me.

WVMoose

iTrader: (2)

Stock was 18 inch rims, 6 ply tires, 35 PSI cold. I have 20 inch rims, 10 ply...

Brokemillwright

I've ran stock, fox 2.0, bilstein, icon 2.0 and back to bilstein, all on my 2014 and with LT tires. When I was running the fox I had larger tires and that itself help smooth the ride, but I was aiming at eliminating my bed bounce and I still had it. Your psi sounds a bit high for empty, have you got a load index chart from the manufacture and figured the rear weight? Also, another option and one that I attempted but never got a call back, is to do a mini pack in the rear. From what I gather that will drastically help the small bumps, but if you tow a lot then you'll have sag unless you use a wdh or bags.

My icons were and are bad in small bumps, my ol jeep on 33s takes smaller bumps tons better than the ford, but it'll squat pretty good with only 500 lbs in the bed.

WVMoose

iTrader: (2)

PSI high for 10ply tires? Gotta remember 6ply tires (generally) have a max PSI of 44-50 whereas 10ply tires have a max PSI of 80, so 44 didnt seem that high at all.

Apples

I am not going to suggest you go against Nitto's "go no lower" recommendation.

I am going to suggest, in an effort to help you be a little happier with your truck's ride quality, you try 40 psi COLD.

If you've been watching your tire pressure readout while driving, you've probably noticed a gain of at least 2 - 3 psi in normal driving, up to 4 more than what you left the house with on hot days.

See what you think. You may always go back to your 44 psi cold which imho is unnecessarily high for an E-Load Range on an unladen 1/2 ton. The best to you. Hope it works out.


Fwiw, a lot of Jeep folks run 35 psi cold in their E-Load-Range A/Ts and M/Ts for the daily run to work and back, and then air down from there for slow trail trekking.

Brokemillwright

Do what you want but that good old load index chart will state what psi for the current weight is acceptable, the 80 psi comes into play when your at the max weight which a f150 won't hold. I know we have different size tires but discount mounted mine up at 44 psi, I run them at 36 and off the top of my head I'm sure I could easily go lower. I run my D rated jeep tires at 25 psi on road and and normally 12 off. Pressure makes a pretty big difference but if your set on the pressure enjoy it I suppose. Crummy screen shot but will give you and idea

Apples

We were saying just now in a towing thread about how it is not unwise to err on the side of caution when presented with "out of the box" thinking or requests. I understand Mark's reluctance to run even lower cold inflation pressures.

That said, the Manufacturer Data Plate affixed to my F150 XLT SuperCrew's door jamb reminds me of my truck's 6800 lbs Payload Package/GVWR. It's axle weight ratings, or, GAWR, are Front: 3150 lbs, Rear: 3800 lbs.

Taking the heavier rear GAWR of 3800 lbs, one I should never exceed, and according to Brokemillwright's posted chart above, I can run 35 psi in my E-Load-Range, 10-Ply, LT285/70-17 and yet safely sustain 2105 lbs weight on each tire. Double that (for one axle) and we see that 4210 lbs tire capacity exceeds the 3800 lbs GAWR... so I'm good to go using 35 psi.

For what it's worth, however, with my set of E-rated LT tires I simply use the factory-recommendation-for-the OE tire of 36 psi Cold, because I'm using a tire that is of similar proportion to the OE tire (a 70-series, 17" tire). When I put the 265/70-17 A/Ts back on the truck for the time being, I run those at 36 psi Cold, too.

tuflehundon

My truck had factory 20's and came with 275/55/20 tires. PSI listed on the door is 35psi.

redranger04g

For what it's worth, that chart almost perfectly aligns with the PSI that Ford recommends for LT tires.

The HDPP trucks come with LT275/65r18 tires with a recommended pressure 48 psi. Front GAWR is 3750 lbs and rear GAWR is 4800 lbs. Let's assume 4800 lbs as the worst case. The chart provided by Brokemillwright shows 2,310 lbs @ 45 psi, which doubled is just below the rear GAWR (4620 vs 4800). Add another 3 psi and it's almost exactly correct. I'd feel very comfortable running 35 psi in LT tires even with a load.