Airing down question

[Dafinga]

Hi Folks,

I am the owner of a Hawk on a Tundra flatbed running Cooper AT3 Load Range E tires. I love the tires. They have been great on the road and in the snow and ice. I am ready to do some offroading with the rig and I would love to hear some psi numbers that I should be airing down to. I know that I can't go too low on the E rated tires but what are folks running in the loose dirt/sand/rock?

Thanks,

Pete

 

[Wallowa]

Hi Folks,

I am the owner of a Hawk on a Tundra flatbed running Cooper AT3 Load Range E tires. I love the tires. They have been great on the road and in the snow and ice. I am ready to do some offroading with the rig and I would love to hear some psi numbers that I should be airing down to. I know that I can't go too low on the E rated tires but what are folks running in the loose dirt/sand/rock?

Thanks,

Pete

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Pete,

You will find a ton of advice on this topic..my 2cents...'05 Tundra AC w/'16 Hawk...same tires as you...last Spring was first trip on new tires...carried 60psi for load [excessive] and to lessen punctures ..Southern Utah/Northern Az...some very deep sand at White Pocket and tons of sharp rock on White Rim Trail...we never aired down; just my preference...loved the tires off road and on highway...

I carry a top of line compressor but have yet to need to air down....given really muddy conditions, perhaps, but so far not needed...we did go with narrow profile [LT235x65x16R] tire to cut into mud/snow rather than float on it...also better to prevent hydroplaning on pavement [higher pressure, deeper tread and slower speed to reduce skating on water]....anyway, just my way and not necessarily the best way!

Phil

 

[campito]

I have an 06 Tundra with Fleet, Michelin E rated tires. I travel at 50/55. I live in Bishop so am frequently on dirt roads. I seldom air down unless I'm going to spend hours on washboard, like out to the Racetrack in Death Valley. Even then I only go to 40/45. I have 4x4, but am seldom in really hard core terrain that may necessitate lower pressures.

 

[camper rich]

I have E rated Michilin A/T's on my Dodge 2500 with a fully loaded Grandby. Normally, on pavement I run 68 front and 78 Rear. On washboard I air down to 45 front and rear, and on soft sand I will go as low as 18 to get myself unstuck. I was using my truck (with camper on) daily to launch and retrieve my boat on a sandy beach in Baja. I do have a good Viair 100% duty cycle pump to air back up quickly.

 

[bajaphile]

What year Tundra? What size tires? What does the door jam sticker state?

For me, it depends on terrain. Many roads I travel have sharp volcanic rock, so I tend to remove only 10-15psi from my road pressure, so that the sidewall isn't in harms way of getting sliced open. When on soft sand or long washboards I'll drop 20-25 psi. Your main concern is to not pop a bead. Try to remove only the amount necessary.

On my 2001 F350 4x4 I run 55/65 psi with 315/75r16 tires for street use with the above psi drop for the conditions I travel most.

While on the topic, I have been using Superflow air compressors since 2003 (MV-50's and MV-90 now). I am on my 3rd one, highly recommended and affordable:
https://superflowair.com/collections/tire-inflators/products/mv-90-air-compressor-high-output-heavy-duty

 

[wicked1]

I run about 65/75 highway, and have aired down to 25 on sand and washboard roads. E rated tires (KO/2).

I am curious how low I can go.. I know the hardcore guys who can quickly reseat a bead in the field will drop them down to single digits, but I'm not willing to take that risk.

 

[Mighty Dodge Ram]

I don’t carry as much weight as you do but I regularly run air pressures 50% of street pressure when offroad, especially on washboard; that means 25# up front and 30# in the rear. Even more so when in beach sand, low double digits. The Aussies regularly lower their pressures into the 20s and they carry loads that are equal or close to your specs. You’re ahead of the game with LT-E tires, they have stronger sidewalls. Not sure about the Coopers but many have 3-ply sidewalls. My Toyos are 2-ply and work just fine. Key points: a higher aspect ratio means a taller sidewall, that’s good. Drop your speeds, speed = more heat. Check your tires often. I give them a good look several times each day when we stop, and I “inspect” them either at the end of the day or before starting out in the morning. bajaphile makes a good point re: popping a bead. I haven’t seen it often but it seems that happens more often when a tire that is markedly wider than the rim was designed for is run at too low a pressure, usually when turning sharply at low speed.

 

[ntsqd]

This thread made me realize that I mostly operate under the Rule of Ten. I run the tires on our camper truck at 50 cold on the highway (max for those tires). On really rough wash-board I drop them to 40. My previous '84 Xcab Toyota and now my '88 4rnnr both like 30 psi on the pavement. The rare times that I do/did air down it was to 20 psi. Still working with the FSB to determine it's ideal pavement pressure (looking like somewhere in the 33-35 psi range) and I've yet to need to air it down for any reason. The wash-board to the Trona Pinnacles didn't require it, nor did any of Nadeau Rd. Proves that a supple suspension makes airing down for comfort only, unnecessary. Airing down for traction is something that I rarely need to do. Maybe because I insist on at least a rear TAD if not one in both axles so as to not need spinning tires to get somewhere.

 

[craig333]

You can probably air down more than you think you can. The Jeep I'll air down to 8psi in the snow (12psi on the Nadeau Rd.) and the only time I lost a bead was when the rear tire dropped into a hole. The truck I haven't figured out just how low yet but I'll air down to forty at least.

Bout time to tell this story again. I'm towing the Jeep to a run in Central CA. I'm on a dirt road and its raining. Lose traction in the mud. Its not deep mud but towing the Jeep isn't helping. I can't disconnect the Jeep because I'm on a Hill. After some cussing airing down finally occurs to me. It took an hour, air down one tire, back in the truck to warm up, rinse repeat. Its a really good feeling when you put it in gear and the truck starts to move. Phew.

 

[ntsqd]

I myself probably could go lower, but I've rarely seen the need. That is what my experience has been, but it should not deter anyone from going lower if they think it prudent or necessary. Most of us at one time or another have seen the vehicle stuck that a simple airing down would solve, but the driver won't hear of it. That is the guy you don't want to be.

I was once stuck in the Santa Clara river bed with a very experienced friend. We're in his 2wd CC service bed late 70's Chevy locally known as "The Behemoth". The bed was loaded with tools on one side and camping gear on the other, with nothing inside the bed itself. He gets out and grabs a shovel to dig ramps to get us back up on the surface. The sand and gravel that he's removing he's tossing in the bed. No airing down, truck drove right out of the stuck. Didn't even take all that long. Totally amazed me, he said it's a trick that he learned going to Baja as a kid with his dad. It is how all of the locals near their place got unstuck.

 

[craig333]

I had a 2wd pickup that I kept an inner tube filled with sand in the bed. Never needed the sand but the extra weight helped a lot.

 

[Dafinga]

Thanks for all the responses!

 

[UmkaAndHawk]

Cooper ATX, 275-70-R17s on Hawk shell on a Tundra



I run 45/50 front/rear on the highway, and 25/30 on rocky and washboard roads. Frankly, I notice way less difference than I would imagine. The number were the recommendation from the off-road shop who installed the rims and tires.

I wouldn't go as low as the 15-20 psi minimum which the off-road place suggested other folks go to...with the camper on...because, well, the camper weighs a thousand pounds.

Good luck, and keep us posted!

 

[camper rich]

When I go 15-18 lbs, it's only in really soft stuff for short distance and at low speed. Usually not more than 1/4 mile from camp to beach and back. Never had a problem with that with my 3/4 ton Dodge and Grandby. At 45lbs I never drive over 45 mph on the E rated tires. In Baja I would drive from Los Frailes to La Rebira (20 miles with 10 being washboard and 10 pavement) and then pay the llantera to fill up the air to 65F and 75R for the highway.