what psi to air down?

What PSI do you air down do?
I've always heard 20 is good. Did that on rocky mountain trails with no issue. Plenty of traction on the abrasive rock.

However, I recently did a sandy trail, and the tires kept slipping. I couldn't find a way to burnout/warn them up. I know these Method bead grips can air down lower.

So I stopped, reduced PSI to 17-18, but unfortunately it made the ride height lower and more likely to scrape underneath
I don't know if it actually made a difference, or if 20 would've been fine.
I think at the end of the day, with A/T's and the fact it was sandy, simply meant I had to pick my line accordingly and that it'll slip no matter what.
In other words, overshooting left to go straight, knowing when moving forward it will slide right.

Curious to hear what everyone does re: best PSI to air down to

 

Some guys go under 10, I stick to 18-20

 

Depends on if you have bead locks and type of terrain. I've aired down my KMC's to 8psi on rocky terrain but on a non bead lock rim I wouldn't go under 15-20psi.

 

I also have bead grips and 12-14 has worked great for me. Slow crawling in rocks. At the beach 12-15 but I'm mostly driving from A to B down the seashore - no high speed turns. When I'm wheeling one of my goals is to not slip. If I spin I try another line. I'll have the occasional bump but I usually target 13 and have been good.

 

I've always gone to 12psi. Did that for many many years on standard steel wheels and never had a problem. I have Method bead grips on my new tacoma.

 

If it's not a paved road I'm at 17psi. It works for high speed and lower speed rocky runs for me.

 

"Best" PSI will depend on many factors. Understanding how your truck and combination of equipment works is more important than knowning a magical one-size-fits-all set-and-forget PSI.

If you haven't experimented in the field yet, the safe starting point according to most is 20 psi. As others have said going lower with non-beadlock wheels will be entering territory where you could start having issues de-beading more easily.

Another factor not yet mentioned is your tire's load range. Something with a C load range will take less airing down compared to an E load range tire which has much stiffer side walls (disclaimer: this is a very broad generalization).

Yet another factor is tire temperature. When you are slow speed wheeling this doesn't matter, but if you air down and then do high speed sections or lots of on-road driving you could be overheating the tires which could lead to failures, possibly catastrophic ones that you don't want. Understanding how your selected PSI affects this is good knowledge to have. Quick & dirty way is to carry one of those small infrafred thermometers.

 

aired down to 17psi which seemed good until I hit this surprise at the end of a trail

steepness not shown in pic
Wish I tried lower PSI to see if that helps be easier on the clutch getting up

anyway, didn’t want to mess with million mile wiring of

$91 ViAir 88P Portable Compressor Kit (12V, 120 Psi, Forup to 33" Tires)

ViAir 88P taking forever in the dirt and worrying about it falling over after on the floor super hot

instead drove like a mile to gas station air used that
Is that bad? Kept it under 45 if not 35mph on the way there

im hoping not
4Runner behind me at Black Bear Pass driving said he didn’t even air back up to make the road drive to Imogene and was fine

so far only noticed one tiny damage or two to a single tire but guessing that’s from a rock and not aired down enough, and/or steel bumper or something not trimmed enough. Still working it out trial and error

was max 2nd gear 4HI on flat parts in hindsight maybe should’ve went slower there or ran higher pressure during that section

 

My bottom is 14….whenever I dream that I’m wheelin….

 

Sandy beaches, Id go as low as 15 on a non beadlock wheel.

Rocks and offroad 17-20 depending on comfort

 

I have the method bead grips and am now in the 9-13 range with Patagonia MTs. I've gone as low as 6 in the snow. All slow driving. I have one trail spot where the back tires would skip/hop when at 15. At 10 it crawls right up. Definitely worth experimenting and if you have a 5th tire on hand you're OK if you slip a bead.

.. and to the question a few notes up about 1 mile at 17psi. not an issue.