CarlJensen

I used a large piece of builders chalk to put large stripes on the surface of all tires and rolled them warm for about 20 yards or so to check contact at different pressure. Mine gets best contact at 60 front and 55 rear. Not very scientific but better than guessing. Take rear up to 80 when towing the fiver.

phox_mulder

Been a while, but I think that's what I ran back when I had E's.
Maybe 65/55.


Now I'm stuck at 50/45, wish I could get 15 more in the fronts.


phox

Mopar1973man

Phox,

I got Load range D in those Big-O's XT that's a go reason why the lower numbers...I figure about the same as you...

And CarlJensen,

I like that Idea of the chalk line on the tire... It would show you if your over / under inflated on tire pressures to your load! Great idea!! One to file away for later on...

kd460

I like 85% of max pressure while empty, max pressure while loaded. Kevin

TxDiesel007

I have always heard

that you are supposed to go 90 percent of maximum tire pressure for these large (3/4 ton and up) diesel trucks.. I have always run 60-65 on these tires 285 BFG all terrains, and am running the same on the current Liberators I just put on my truck. Based on other experience on my F250 IDI using 235-85-16 Goodyear AT/S tires, i ran 75 lbs of pressure.. a really really stiff and bouncy ride, and i got 65K miles out of them with regular rotation.. Perhaps I myself ran them too high, ive heard of people getting more, but for 420 dollars total, mounted and balanced at SAMS club, i think that was good enough.. Mind You my truck was regular cab, long box 4x4... too, and towed alot..

By the way, most of the time i didnt run over 70 lbs of pressure, even while towing, im in no hurry to get there, just try to be careful... just my experience...

TxDiesel007

RickCJ

Did anyone look at the sticker in the driver door jamb? DC allready has the tire psi figured out!
60 psi front/50 psi rear This psi will work loaded or unloaded. If you need more air in the rear, you are overloading the truck!! 2 fronts at 60 psi will handle 5000 lbs. 4 rear tires at 50 psi will handle 7500 lbs. 12,500 my trucks gvwr is 11k.

TxDiesel007

I agree with 59 Ford

On his slogan..

Forget the mule.. just load the wagon.. i know i do.. and if it breaks ill fix it..

Tx

mkubacak

Yes, if you still are running the tires that came from the factory. Each manufacturer has different recommendations based on tests done with those tires. If you are running a different tire, you will need to adjust pressure.

By your reckoning, I can at 120 psi have 4,940 lbs. x 2 = 9,880 lbs. on the front axle and 4,675 lbs. x 4 = 18,700 lbs. on the rear axle. Wow!! I never did the math before. That is 28,580 lbs. based on tire ratings. I would hate to see how bad the truck would sit loaded like that.

mestdagh

My door sticker say 60 front and 70 rear. I assume that's w/ a payload otherwise it doesn't make sense. I'll check tomorrow to see see what the dealership did w/ pressure on my stock tires.

Rare1

The inflation pressure on the tire sidewall is not the "correct" pressure, it is simply the maximum pressure recommended for that tire by the manufacturer, and they give the load rating for that pressure. Use the max pressure if the weight on the tire equals the maximum load capacity printed on the sidewall. If your load is less use less pressure, that's common sense. All tire manufacturers have charts for each tire showing what pressure to use for various load on the tire.

Dodge says my front end needs 50 psi at maximum load, but I use that empty because with less pressure my steering feels mushy. I use 60 psi when heavily loaded just for a margin of safety, even though weight in the box doesn't add much to the front.

In the rear with no load I inflate (deflate) until the sidewall bulge is the same as the front. This is 40 to 50 psi depending on ambient temperature, and gives a nice ride with 350 pounds of sand in the bed (and the Ranchos turned way down). When I load the camper I consider this a "full load" and inflate to 80 psi for the maximum capacity of the tires. This provides some safety margin and better milage.

xp8103

Set 68 rear, 72 front. Also set my rear ranchos up to 5. Was at 5-3. Now at 5-5. Rear is much stiffer now. May go back to 4.

latitud_rt

This is a good discussion. I bet lots of people will be checking their pressures. Maybe even checking tire pressures in the "other" vehicles also. I try to check mine about once/month. They very rarely need adjusting. I also inflate my rears to 75 - 80 when towing the 5er. The only thing that keeps us going in a straight line is 4 little contact patches (or 6 for you dually guys ) It never ceases to amaze me the people that never check or maintain their tires and then complain when they fail.

xp8103

I agree. But what is "proper" inflation seems to be still up in the air (pardon!) There is at least a 20 psi difference in some of the settings described herein.

latitud_rt

User preference vs ride comfort. As long as they are not severly underinflated, they will be fine. Driving habits have a lot to do with treadwear as does inflation. Agressive driving, cornering, acceleration will play a huge roll in how the tire actually wears. Inflation is important but find something acceptable to your situation and make adjustments as loads increase or rapid tire wear is noticed.

dsldan

I ran the Mich 235/85/16 E on mine with 65 front and 45-55 rear depending on load and got 70k from the tires, all nice even wear, could have gone longer but wanted better tread for snow. You should have with your owners manual a tire book showing the load and presures for the different options and tire sizes. If you dont let me know and i can send you one.