Full size diesel rig owner "E" rated air down ?

[Daryl 32]

As stated - I am wondering how low you go with airing down your "E" rated tires on your full size diesel rigs?

I run mine at 60 to 65 in the front and 3 to 4 pounds more in the rear when not towing, total weight of our truck is 7,300 to 7,500 when loaded for over night.

I was thinking maybe 25 psi? - came up with this by thinking of percentages when airing down a tires ran at 32 to 35 on highway to 15 to 14 off road.

All input welcomed - Thanks Daryl

 

[OffroadTreks]

My rig isn't a diesel, but I'm actually about the same weight as your loaded, actually even more. 7864 last time on the cat scales.

It really depends what I'm wheeling/driving on. Sometimes on washboard/rough dirt road I'll run between 32psi-40psi because I figure why bother airing back up at those pressures for the highway.

When I'm on rock, sand or doing actual crawling I'm usually between 18psi on the low end to 25psi on the high end.

There is no "right" pressure. Air down to what you think, if you need more traction or the ride is still rough, air down some more.

If you don't have bed locks however, don't air below 12psi. I've pretty much stuck to 18 as my default for extreme wheeling. And then usually 22psi -24psi range for a lot of other rough stuff.

 

[Daryl 32]

Thanks B A - seems I was close with my thoughts.

With the 99 2WD SD the front tires go way over on the outside in a turn, so even at 55 to 65 PSI it looks like the tires are getting pulled off the rim on the street. I realize they will slip off road but was just wondering.

18 PSI most look also most flat with our weights! LOL

I have an ARB twin pump mounted on the truck with a 2.5 or so tank mounted on the frame, went with the ARB twin because of the PSI we have to get back up to.

 

[Raul B]

I dropped mine down to 20psi at the dunes with no problem... I was running 37" tires back then... it was a F250 crew cab short bed

 

[OffroadTreks]

I've never had my tire look like it would come off. But it does it's job of softening the impacts and gripping rocks. I run Toyo Open Country AT/II's in 35x12.5R17 right now. Moving up to 37's soon.

 

[CatButt]

My Grapplers at 16 psi barely have noticeable belly to them. I am sure after more miles and more miles aired down the plys will loosen up a little. But each tire, even a 12 ply E will likely need a different pressures to achieve a particular level of grip. 16 psi is WAY too low and I have a nail and a slow leak, but just play around and see what works best for you.

 

[Daryl 32]

Just did a run today, not real hard but have some rocks and good size ruts. Dropped fronts to 35 and rears to 32. truck plugged away and never stopped. Having the locker in the rear has really made a great difference. This was the first time in dirt/hills with obstacles to climb and go over.

 

[boss324]

Not a disiel but E rated on the burb and usually run them at 30 psi offroad oe is 50/80. This past weekend I ran some pretty rough terrain and should have ran them at 20-25psi.

Sent from my SAMSUNG-SM-N920A using Tapatalk

 

[Scott]

I run my 35" load range E tires at around 25 psi offroad and it seemed to work out great for the last few trips.

 

[crit_pw]

Like Bold Adventure stated our trucks weigh in heavy even though we aren't diesel (Power Wagons). I run the 37x13.50 17 Toyo Open Country MT load range "E" on my rig. I don't run the higher pressures that many do on the pavement and will typically keep my fronts at 40-45psi and the rears at 35-40psi. When I do air down I run 25psi in the front and 20 in the rear. I haven't had the need to go any lower for traction at this point. I have wheeled with Bold Adventure and his rig performs very well with the pressures he ran when we were in Moab this year. As he said its a bit of trial and error. Find a lower pressure your comfortable with and adjust up or down from there. Having a way to air up on the trail can make these trial and error adjustments a lot quicker to get through.

 

[Jeff Graham]

Many overlanders airdown for a more comfortable ride, not necessarily for addition traction. On graded dirt roads, more traction isn't really needed most of the time. When you are airing down for traction (sand, mud, technical trail, etc.) their are lots of factors that come in to play. The weight of your vehicle, when loaded on the trail. The tire sidewall structure. A good rool of thumb is to airdown, until you see the wheel sidewall starting to bulge out a bit. With a full size rig, with a heavy load, this will happen with much more psi (when compared to a light vehicle). Deflate until you see the bulge starting, and check psi. This will be a good start. Add or subtract from this starting point, depending on terrain. Just be careful not to go too low, unless you enjoy reseating wheel beeds.

 

[Notedhillbilly]

I'm a diesel, but about half your weight. I haven't found the need to air down yet, but most of our areas are not to gnarly.

Turbo Diesel YJ

https://www.overlandbound.com/forums/index.php?threads/8019/

 

[OffroadTreks]

Many overlanders airdown for a more comfortable ride, not necessarily for addition traction. On graded dirt roads, more traction isn't really needed most of the time

I tell you, there have been so many times I've been going down some washboard road and repeatedly said "I wonder if I should air down" because the ride was rough. I know now if I'm asking myself that, I should just air down and stop wondering. LOL