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chuckie
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Location: Kansas Prairies
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TIRE PRESSURES?
We have been talking about tire pressures and "airing down". I have been doing that as a matter of course, for years..BUT then the question came up:
"Air down to what?". I cant honestly remember ever checking the lowered air pressure. I do it till they "look right'...Anyone have any suggestions on
the correct pressure? Thanks 
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BajaWarrior
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In a full size crew cab 4x4 with 35's on it I have aired down to 15 for beach driving, and that includes boat launching. It crawled everywhere easily.
I have two Toyotas that are full timers in Baja also used for launching on a soft steep beach both trucks have 33's and I keep them aired down to
about 7 psi but slightly higher for the desert and slow speed paved roads.
A good sidewall is important when airing down especially for washboard/rocky roads like the former road to Gonzaga.
Haven't had a bad trip yet....
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woody with a view
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every tire is different. last october at la bocana we headed north to the beach with the same 18ish pounds in each tire. the tide was just going out
so i hugged the wet line trying to find the firm spot. i sank almost to the frame.
the chinese fire drill ensued with me letting more air out of all 4 tires while Bia grabbed the shovel from the back to dig out the sand in front of
each tire. this while each wave came to within 10 feet of us (i read the tide book right, RIGHT???)
we survived that potential fiasco with the knowledge that Your Pressure May Vary daily due to the conditions, not to mention your tire....
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Hook
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BW, are you running load range D or E tires on the Ford?
I am running load range Es and I am wondering how LOW I can GO, if I got in a real fix? Soft sand is the fix I'm talking about.
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Curt63
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You can go down to 8 lbs for sure. some say lower but Ive never done lower than 8
No worries
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woody with a view
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just don't bust the bead.....
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David K
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You may have to experiment and naturally have a air pump to re-inflate. The type that connects to the battery with clips is three times faster than
the type that plug into a cigarette lighter.
As stated above, vehicle type, load, and tire type has a lot to do with how much air to remove.
For deep sand, beach sand on the Cortez side (more difficult than the Pacific side sand)... more air needs to be removed.
Street or bald tires do better. All Terrain tires do well. Mud terrain tires and 3 ply sidewall tires do poorly... if all these types are at the same
air pressure.
To equalize them for sand floatation (that's the key, to float on top and not dig in), more air needs to come out of a mud terrain tire than an all
terrain or street tire.
The goal is to be able to drive across the soft, dry sand without struggling for power... a sign you are digging in more than you are moving forward.
Typical for all terrain tires is to drop the pressure 50%, and for a mud terrain or 3 ply sidewall/ heavy tire to drop 75%...
This depends on the vehicle weight, load in vehicle, climate (dry air vs. humid air) and of course the type of sand.
Experiment! If you start to get stuck in sand... stop, clear away built up sand from the tires, and let more air out until you find the sweet spot for
pressure that day.
When deflated, avoid sudden turns or hard braking... roll to a stop and make wide turns... don't risk the trie popping off the rim if your pressure is
less than 10 psi.
The tires I now run on my Tacoma are Hankook Dynapro ATM 265/76-16 and 18 psi is their sweet spot (35 psi on the street). The BFG Rugged Trail TAs
that it came with worked fine at 15 psi (32 psi on the street)... I have gone as low as 8 psi once, when I was getting stuck between the incoming tide
and a sand dune, after stopping to check out a dead whale on Shell Island about 9 years ago.
BEFORE and AFTER DEFLATING (7-18-10):
At 32 psi and with traction control in 4WD-HI, I was able to drive across the soft sand and onto the wet sand, but as I was fully loaded, the excess
weight caused the tires to dig into the loose, wet gravely sand (crushed sea shells).
I dropped to 15 psi, and drove ahead with ease... I circled back to take photos of the difference...
When correctly deflated, the tires will not go as deep into the sand as a human foot print!
I repeated the test with the new Dynapro tires...
So, if you are struggling in sand, let out more air! 
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Neal Johns
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Harry Lewellyn is the man for tire pressure (and DK is in the same ball park).
http://www.4x4now.com/sfjun96.htm
My motto:
Never let a Dragon pass by without pulling its tail!
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David K
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Excellent link, Neal!
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TMW
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Just before the 2010 Baja 1000 I was down south pre-running along the Pacific coast about half way between Sant Rita and the turn inland for La Paz
when I came upon a beautiful beach area at the mouth of an arroyo. So I turned my GMC Z71 toward it. I went off the hard packed road into the sand and
within 50 feet I started digging in. I stop get out and air down my BFG TA KO LT285/75R16 tires to 20 lbs. I start backing up and I get maybe 3 feet.
I get out and air down to 15 lbs. I back up another 3 feet. I get out again and air down to 10 lbs. Get in and back up to the hardpacked road, no
problem. I Air up and leave.
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Hook
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| Quote: | Originally posted by woody with a view
just don't bust the bead..... |
Yeah, that's REALLY what I'm asking.............where is that likely to occur on load range E tires, whose max inflation is 80psi.
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woody with a view
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practice at home is all i can say. there is no "one size fits all" answer. depending on what you're carrying, road surface, etc....
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Hook
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| Quote: | Originally posted by woody with a view
practice at home is all i can say. there is no "one size fits all" answer. depending on what you're carrying, road surface, etc....
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I think I'd rather practice at a llantera. 
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woody with a view
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David K
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Location: San Diego County
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"Typical for all terrain tires is to drop the pressure 50%, and for a mud terrain or 3 ply sidewall/ heavy tire to drop 75%...'
The 75% rule for you is the area that will probably work best Hook... that would be 20 psi. Do the tire steps where you feel safe doing it, not where
high tide will cover your truck!
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Hook
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This video is what really got me thinking about tire pressure. This guy has cojones of steel. I cant imagine attempting this..............but he's
floating on sand with a lot more weight than I have.
http://www.youtube.com/watch?v=tTNkRRgaSyE&feature=relmf...
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msteve1014
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Hook, I have a F-350 diesel and have been down to 15 psi with very good results, and no problems. My camper is alot lighter than that lance, but still
alot more than an empty pickup.
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Hook
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| Quote: | Originally posted by msteve1014
Hook, I have a F-350 diesel and have been down to 15 psi with very good results, and no problems. My camper is alot lighter than that lance, but still
alot more than an empty pickup. |
Are you running LR D or LR E?
265x75rx16?
And was that with the camper on?
Thanks for your reply, Steve.
[Edited on 4-21-2012 by Hook]
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Skipjack Joe
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Sometimes, when I lower the tire pressure I wake up the following morning with a flat tire. 
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msteve1014
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| Quote: | Originally posted by Hook
| Quote: | Originally posted by msteve1014
Hook, I have a F-350 diesel and have been down to 15 psi with very good results, and no problems. My camper is alot lighter than that lance, but still
alot more than an empty pickup. |
Are you running LR D or LR E?
265x75rx16?
And was that with the camper on?
Thanks for your reply, Steve.
[Edited on 4-21-2012 by Hook] |
I have 285/75-16 E tires. That was with the camper on. Fully loaded with the camper, boat, motor, honda 90, and all the extra crap, I would guess 2000
lb. max on top of the truck. The tires look pretty flat at 15 to 20 psi.
[Edited on 4-22-2012 by msteve1014]
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