Off Road PSI

I purchased a 2022 4runner TRD Off Road back in April. At age 53, my dream vehicle is FINALLY in my possession! I am not an experienced off roader by any means. I do not currently have any plans of ever getting to that level of actual Rock Climbing etc, however I will be heading out to Ouray Co in a few weeks. I have been looking at some fairly low key drives (Last Dollar, Cimmaron, Owl Pass) and am curious what is a good PSI to run my KO2's while making these drives? I am thinking around 23-25. Thanks in advanced for any input!

 

Welcome and good looking truck!

 

On moderate short trails i do 25psi but it may be more comfortable to go lower.

 

I run 20psi in my 2nd gen.

 

I've dropped to 20 psi

 

20 psi (easy) or 17psi (moderate) is the sweet spot for me in terms of comfort.

If it is a technical trail and I know I really need the grip I go down to 15 psi

 

I drop to about 20 on any tire.

 

17 for the win

 

Try different ones, it may vary depending on terrain, conditions, how much you time you want to spend reinflating, load range, etc.

Heck, I've tackled some at street pressure just to see how it was.

 

I run 24psi up front and 19psi in the rear all day every day, whats this "airing down" nonsense you guys are talking about

 

Thank you all! Looks like 20 for the win!

 

This, but I typically default to around 17psi if unsure of obstacles on the trail

 

23-25 sounds like a good starting point. When I had stock size tires, I generally ran 20-25 depending on the terrain. I'd run as low as 18 in rocks or sand.

I run 12-15 with my current tires. But, I'd never consider running that low on pavement for any real distance.

 

Welcome

 

I run 34.

 

14PSI non pavement only

 

20 psi for me....but I think my lower back will feel better it i go to 15psi. I am just honestly worried that I might pop or mess something.

 

Some of this info might apply, especially the optimum flat foot print. Based on my roughly 50+ years of driving on deep soft beach sand.


1. Airing down



Some folks think airing down (lowering tire pressure) is not really necessary and while that is true for some vehicles, there are reasons why you may want to air down regardless of your thinking on this, even if you have nitrogen in your tires.
A vehicle aired down properly to a nice flat optimum tread footprint rolls more easily mostly over the sand rather than mostly pushing down into and thru the sand with hard tires. Thus less torque is required to move the vehicle and less strain on the engine and drive train.
Additionally hard tires tend to give short way less than a full revolution spins as they push thru the sand. This kicks back a little sand forming a washboard / speedbump affect in the sand. The ride is thus more uncomfortable for you from the spins and very uncomfortable for those following.
Now some don’t want to air down because they worry about tire damage / wear on pavement and many carry portable pumps to air up immediately after coming off the sand or at least as soon as they can get to an air station. This really is not necessary if you are at the optimum flat footprint. I air down upon arrival and sometimes stay that way for weeks, only airing up if say I’m going to go from Salvo to Nags Head area. Over the years and many sets of tires I’ve seen no appreciable difference in tire wear than what I would expect at full street pressure.
Now that said there are things to consider when aired down. More sidewall heat is generated as the sidewalls flex more, but if speed is kept reasonable (even 55 mph or less) for the short distances you would travel around the beach area on pavement, it would not be a problem. Also handling, especially in sharp cornering, is affected as the tire tends to “roll” more to the side of the rim in a turn. But again, reasonable speed and avoiding sharp cornering should give no problems. Gas mileage is slightly affected as it takes a little more effort to move the vehicle.
Now you can air down “too much”. When you go below the optimum flat footprint the center of the tread tends to concave in toward the rim and even in the sand you tend to ride more on the tread edges and the hump of sand in the middle adds to the torque required to move the vehicle. While not as bad as hard tires in the sand, it will tend to result in more “digging” from just the edges and pushing thru the sand. And it will cause excessive tread wear on the tread edges on pavement, plus way more heat in the sidewalls.
In addition sharp turns at very low pressure, as in trying to move over out of ruts, can result in breaking a tire to rim seal. Plus if torque is applied when you start to bog down the low pressure can result in the rim spinning inside the tire if the edges “grab” the sand again breaking a seal. I’ve seen this happen on a couple of occasions, one having two seals broken, thus no help from the spare.


I learned years ago from some desert rats the optimum footprint for sand. It is not a one size fits all so you will have to experiment a little to find what fits your setup. Your vehicle should roll rather easily “over” the sand and not require a lot of extra power (torque). And remember street pressure is not necessarily exactly what is on the door placard. The placard is nominal for a nominal load (usually indicated on the placard). Both street and sand pressures are load dependent (including passengers, gas, etc) and may vary front to back, depending on how you are loaded.


General rule is with vehicle loaded like it will be on the sand and vehicle on level pavement and tire pressure at recommended street pressure, measure the height from pavement to edge of rim. Then lower pressure until the height is ¾ of street pressure height.


When driving in the sand, slow steady progress is best. If you start to bog down, stop. Back up a few vehicle lengths in your tracks and then go forward again with slow and steady. Try to avoid spinning / gunning it as this will generally dig you in.

 

For easy trail rides you can go down to 9 psi with no risk of popping a bead, though some tires (like Copper ST Maxx) become prone to debris ingress at the bead area. I usually go down to 15 psi. Lower pressure = more comfort and more puncture resistance.

A tire is the most puncture- and cut-resistant at 0 psi, which is why it's advisable to completely deflate the spare on harder trails.

 

8

 

I go 17-18 in my 4th Gen. Whatever you decide, I highly recommend Over-Sand deflators. They’re solidly built and provide exceptional precision in choosing your pressure. Terrific customer service too.