[Mmiguy2103]

hey guys. I would love to see what everyone runs in their tires while off road? So i have onboard air in my truck so i can refill my tires anywhere. I am wondering what is a safe psi to run some 285/75/16 mud terrains on stock rims at without having any issues. not running at high speed.. i am talking 25 mph max but mostly 5-10 mph on rocky dirt trails. just would love to soak up some of the bigger stones and rocks with out having any problems with the bead popping off.

 

[Taylor21554]

Where I live south Florida ... we have tons of “washboard” roads... I mean I usually drop to about 25 psi just to smooth out a bit, I’ve heard people go down to 22.

 

[erturne]

Andrew St Pierre White has a table of pressure reductions in his book "Four-Wheel Drive". He's spent a lifetime driving off road in all conditions, so it's probably a pretty decent guideline.

Assuming you normally run 35 psi...

Gravel/corrugations - 10-15% drop to 30-32 psi
Rocks - 15-20% drop to 28-30 psi
Mud - 25% drop to 26 psi
Sand - 50-60% drop to 14-18 psi

It comes with a bunch of caveats about driving conditions and speeds, but you'll have to read up on it to find out more.

 

[DanB2019]

I've been dropping to around 18 PSI on my OEM 265/70's, and it has worked well on forest service roads and some mild rocky areas. I dropped to 15 PSI with the 31x10.50x15's I ran on my Cherokee, but the sidewalls were stiffer than the factory tires on the Frontier.

I can't imagine running 28-30 PSI on rocks. I used to run 8 PSI on my non-beadlocked 35x12.50 MTRs on my TJ and some pretty extreme conditions and never popped a bead. The low pressure allowed the tires to conform to the rocks and really grip well.

 

[bajasam]

285's are a little wide to be running on stock rims if you plan on airing down alot . 9 inch wide rims would be alot safer

 

[mtyler11]

When airing down tou want some buldge. How much depends on terrain.
When i run empty on stock roads (think fire service or active logging roads) i run 20 to 25psi
If im on some decent trails i go 15 to 18 depending on how much tire slip im experiencing.
You need the tire to wrap the rock or log.

How to tell good buldge: grab a brick. Air down. Drive up onto the brick. Does it sit up on it or wrap around it? You want the tire to embrace it. Like a chiwawa humping your leg...

285's are a little wide to be running on stock rims if you plan on airing down alot . 9 inch wide rims would be alot safer

I disagree. A narrow rim allows for lower psi because the tire is already forced onto a narrower rim than it "likes". It acts like a poor mans beadlock. You are less likely to pop a bead than on a wide rim. One of the jobs of the pressure is to hold the bead to the rim under side-load.

 

[bajasam]

I guess that's one theory, but 99 out of 100 tech articles don't agree with your skinny rim idea.Probably OK at 10mph going over a rock, but once your up to 30-35mph and have to turn through a curve watch out.

 

[mtyler11]

I guess that's one theory, but 99 out of 100 tech articles don't agree with your skinny rim idea.Probably OK at 10mph going over a rock, but once your up to 30-35mph and have to turn through a curve watch out.

Ive never lost a bead. Friends with wide rims have.
The street "stance" bros with their wicked wide rim and narrow tire that have to strech the tire to seat the bead, they have to run high pressures to keep the tire on.
As to articles, theyre written by mags or other journo companies, right? They have to worry about lawsuits if they deviate from mfr recommendations.
Not saying to run a 5" wide rim. The stock 7" is .5inch below most mfr reccomended rim width. Those rim widths are reccomended to maintain a flat tread at higher pressures and higher loads.
If you monitor treadwear, temps, abnormal wear, ... these will inform decisions.
Also, i dont care what rim size you run... driving at 35mph on 15psi is begging for a blowout.
Lower psi means more sidewall action, means more tire heat, means shorter tire life. If youre driving slowly (which is why youve aired down) you generate heat at a slower rate, allowing the tire to dissipate that heat.
If you can run 35, you dont need to drop below 25

 

[DanB2019]

I ran 35x12.50x15's on 8" wheels with no beadlocks, 8 PSI. Even at 30 MPH plus on the dirt roads (and even some paved roads) heading to the trails from the parking area I never had any issues, you just have to use some common sense and not drive it like a rally car.

Even with the sidewalls wedged against rock walls for traction I never lost a bead or even burped any air. This wasn't a light Jeep, either: 3/16" skids, bumpers, and rock sliders added quite a bit of weight.

Damn, I miss my Jeep....

 

[Mmiguy2103]

thanks guys for the replies. Looks like 25-28 would be the sweet spot for what i will be doing most of.

 

[mtyler11]

thanks guys for the replies. Looks like 25-28 would be the sweet spot for what i will be doing most of.

The only way to tell is experiment. If your tires are slipping alot, drop another 3psi. Rinse, wash, repeat.
There is no exact right answer.

 

[Mmiguy2103]

The only way to tell is experiment. If your tires are slipping alot, drop another 3psi. Rinse, wash, repeat.
There is no exact right answer.

thats what i figured but just wanted to get some input from what others are running.. I am going up to maine in a month for 15 days on vacation and bringing the frontier so I want to explore alot while i am there

 

[mtyler11]

thats what i figured but just wanted to get some input from what others are running.. I am going up to maine in a month for 15 days on vacation and bringing the frontier so I want to explore alot while i am there

Enjoy! Moosehead / Rangely area? Make sure your CB is working. Loggers are not polite and act like they own the road.
For that area, err on firmer tire than softer. The shale eats tires.

 

[Mmiguy2103]

Enjoy! Moosehead / Rangely area? Make sure your CB is working. Loggers are not polite and act like they own the road.
For that area, err on firmer tire than softer. The shale eats tires.

I am staying at 2 different campsites within Baxter state park.. more northeast of moosehead. I have been there a few times as i have family up there in Millinocket. I have been all around the area on my DRZ400s a few years ago when i went. always said i wanted to bring my truck back because of all the great trails everywhere!

 

[Clint]

Enjoy! Moosehead / Rangely area? Make sure your CB is working. Loggers are not polite and act like they own the road.
For that area, err on firmer tire than softer. The shale eats tires.

Based on your input would you carry an extra spare tire?

Clint

 

[mtyler11]

Based on your input would you carry an extra spare tire?

Clint

2. And a repair kit. Ive seen guys go through 4 tires running from NH border to Rangely to Moosehead and up through Aroostic county. Multiple repairs in the tread, only gave up on sidewall damage.
Alot depends on your tire too. Some tires are more sturdy than others

 

[Mmiguy2103]

2. And a repair kit. Ive seen guys go through 4 tires running from NH border to Rangely to Moosehead and up through Aroostic county. Multiple repairs in the tread, only gave up on sidewall damage.
Alot depends on your tire too. Some tires are more sturdy than others

I have a full size same model spare and always carry a plug and patch kit with me and tire irons.. in the past i have removed a tire from the rim and patched a sidewall to get me out of where i was. a set of tire irons are cheap and easy to store in the truck. the key is having onboard air to pump it back up when done

mind you i am not going insane offroading here lol just exploring but hey anything can happen. lucky i wont be alone and will have 2 other 4x4's with me

 

[bajasam]

Make sure you carry those tire spoons with ya so you can put those beads back on those skinny rims.........lol

 

[RyanD1966]

thats what i figured but just wanted to get some input from what others are running.. I am going up to maine in a month for 15 days on vacation and bringing the frontier so I want to explore alot while i am there

We have a condo in Waterville off the KMD and have run extensively in that area. The shale is pretty nasty but often I did not air down just for the expedient of keeping the treads under firmer control, never had any issues. That was with Michelin Defenders which were much more a street-oriented tire but did fine in the moderate rocks. On Tuesday upped the game to General Grabbers AT/X Load E 235/85r16 with carcass protection technology and some beefy sidewall protection lugs to help prevent tears. Haven't been to Maine since mounting them, obviously, but expect much better performance when we do next month.
I'd recommend the Golden Road, Stud Mill and CCC roads and up by Harris Dam.
The Brochu road is pretty good but avoid Dyer's unless you love really really narrow trails that pinstripe your paint and challenge your tire's longevity. We crawled through at an average of 2.3MPH after not realizing how ugly that run was and being pot committed after getting in half-way and unable to turn around. It was an adventure, especially with the wife and my two teenage children along. She's born and bred in Maine so assisted ably with spotting on some very ugly sections.
Get yourself a DeLorme if you can find one. They're out of print but there are many floating around. We have one, cost us $20.00. They have all the unpaved and unmarked semi-major trails & roads documented, but there are tons of camp access trails that are not on their maps.

 

[Mmiguy2103]

Golden road i know about As i camp right near there. i will def check out the others. thanks alot for the reply.