What do you air down to?

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maktruk

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Sand, air way down. 15 psi even

Rocks, also, air down to at least 20-25 psi

Mud is a highly debated subject. Some think the wider footprint of a deflated tire provides more traction in mud. I lean towards the skinny tire way of thinking, but that's from my experience in snow.

Truthfully, that last one simply depends on what kind of mud you're in, I guess.
 

TreXTerra

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I have mine set to 20 psi, which is fine for gravel and washboard. As the trail gets rougher, it is easy to let out more air and soften up the tires if I need to. I will go down as low as 15 PSI or so, but any less than that and I worry about rolling the bead or spinning the rim.

Ronny Dhal has some good videos on tires, tire deflators, and psi.

Tire deflator comparison:

I use the SmittyBilt ones, he has them listed as the cheap "no-name" brass ones. They work ok, but have to be recalibrated if you accidentally tighten or loosen the wrong part of the deflator.

Andrew St. Pierre White also has some good videos on PSI:

One thing to remember is that with lower PSI the tire will heat up very quickly with any kind of speed. At 20 PSI speed should be limited to no more than 50 MPH at the absolute most. As the pressure gets lower, the max speed you drive needs to come down. Driving too fast on aired down tires will cause damage to the tire carcass and the heating may cause the tire to delaminate - remember the Ford/Firestone scandal? That was due to low tire pressures damaging the carcass and causing failures.
 
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WJ - Firefly

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I haven't had to air down on the trail yet. I have a set of TrailHead deflators that are set to 13 PSI. I recently reduced my highway pressure from 35 to 30 and have seen a substantial reduction in mileage. Since there appears to be no change in wear, I will probably re-inflate this weekend and maybe push 40, just to see. The tires are load range E, so the only issue is uneven tire wear.
 

maktruk

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In my early days of wheeling mountainous terrain in CA, I was dumbfounded at how low the locals would take their tire pressure. Forest trails in the Midwest don't really require 15 psi!

So, I was lazy about it...

Here was the result...



Im pretty religious about it now.

In my defense, the BFG Long Trail (fail) tire that comes stock on the Xterra is über soft and squishy.
 

WJ - Firefly

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Off-Road Ranger I

2,771
Casey County, Kentucky
First Name
David
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Goodyear
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KL7JKC
I haven't had to air down on the trail yet. I have a set of TrailHead deflators that are set to 13 PSI. I recently reduced my highway pressure from 35 to 30 and have seen a substantial reduction in mileage. Since there appears to be no change in wear, I will probably re-inflate this weekend and maybe push 40, just to see. The tires are load range E, so the only issue is uneven tire
 

toxicity_27

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I aired down to about 25 psi on the stock 32" KM1s. Wish I would have gone to 20. I run 37 on the street.
 

TreXTerra

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Salt Lake City, Utah
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In my early days of wheeling mountainous terrain in CA, I was dumbfounded at how low the locals would take their tire pressure. Forest trails in the Midwest don't really require 15 psi!

So, I was lazy about it...

Here was the result...



Im pretty religious about it now.

In my defense, the BFG Long Trail (fail) tire that comes stock on the Xterra is über soft and squishy.
The Long Fail might as well be made of soft cheese for how well they hold up. It was designed to be a spec tire to give a nice quiet compliant ride and to flatter the vehicle with a soft rubber compound, they are utterly worthless at anything else.

Time to get a set of the KO2, good luck chipping the rubber on those.
 

Overland-Indiana

Overland Bound - Midwest Regional Ambassador
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Iv'e got Duratracs and haven't had to air down yet, but I used to air down my BFG MT to 20psi on the trail and they worked great!!
 

maktruk

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I run Cooper Discoverer AT3'S now, both on the X and the Frontier.

We see more highway miles than dirt, but want the performance of a dirt tire. Good tradeoff IMO
 
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roamingtimber

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I just set and tested my deflaters to 18. I'll see how I like the tires there and decided if I should go up or down accordingly. Tested out my new viair compressor too. Took 2 minutes a tire to go from 18 back to 37. Not bad in my opinion.
 
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Hank_

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Here in Michigan I run my tires at 30 psi for regular driving and keep that pressure on dirt trails. In the soft sand and snow I will air down to 10 psi. I have done this for 30 years and never had a tire come loose from the wheel. At that low of pressure you don't want to be doing donuts but for straight on wheeling the more flotation in sand and snow the better.

Hank