Air down, or don't when you go rock crawling?

Okay so I know it's recommended to air down when you go rock crawling, but the last two times I've gone rock crawling I've achieved everything that I have without airing down.

Now my first thought when I first went to go rock crawling at the Northwest OHV park in Bridgeport Texas was I would air down when I needed to, except I didn't need to.

Same thing today at Crossbar Ranch in Davis, Oklahoma. I didn't need to air down all day. If anything it benefited me because I had an extra inch or two of clearance specifically because I didn't air down. I only had one point where I rubbed on a rock. It hit one of my cross members on the frame. (Nothing a little bit of truck bed liner can't fix)

So I've been noticing while watching a lot of SxS videos of these guys rock crawling, and going through mud, sure they have mud tires on, but they're also completely aired up. Like big old rounded tire and everything.

Now my personal experience with airing down has been that airing down creates more surface contact, which is cool if you're trying to get out of a situation where you're stuck, but also means in mud and sticky loose surfaces, you're less likely to ride on top of it, and more likely to tear it up.

I'm sure this chat will get pretty technical pretty quick, what are you guys thinking?

Air down, or ride at normal PSI?

Airing down not only improves contact patch, decreases chances of puncture, but I find it significantly more comfortable. Just my 2c.

Doesn't take that much time and the benefits outweigh the costs.

My initial thought is that if you do not need to air down, you are not rock crawling. Then I realized that I was probably just being an elitist a-hole and the trails here in SoCal are probably different that those in other parts of the country. I always air down when rock crawling but my standard street pressure is about 32-36. I find the aired down tires give me a much softer ride and this past weekend being at 13 was too much pressure for the trail I was on so I had to go down to 10.

What pressure are you at before airing down?

Different kind of driving, I understand, but look at them tires...



Same thing here, I get they all have 40"+ tires, but ain't none of them aired down...

Any kind of bumpy offroading I always air down. At least to 15psi. There is the inconvenience/laziness aspect but if you have a good system to deflate/inflate I think it is definitely worth the comfort if not traction.

I'm no fan of mud, but wouldn't more surface area make you more likely to ride on top of it instead of less?

More grip, less chance of puncture, and more comfort. Yes, I air down whenever I go rock crawling.

Hell, we air down when doing long-assed washboard roads. The one behind our place is over 40 miles long. That'll beat the crap out of you and your rig if you don't air down. Add a spouse to the equation and you'll air down even more often.

dragoneggs said:

Any kind of bumpy offroading I always air down. At least to 15psi. There is the inconvenience/laziness aspect but if you have a good system to deflate/inflate I think it is definitely worth the comfort if not traction.

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I have those coyote deflators set to 18 PSI. I just have yet to use them myself yet. Maybe I'm not doing hardcore enough shit, but I've yet to run into an instance where I don't have plenty of grip at 33 PSI in my 35-in tires

Tredsdert said:

I have those coyote deflators set to 18 PSI. I just have yet to use them myself yet. Maybe I'm not doing hardcore enough shit, but I've yet to run into an instance where I don't have plenty of grip at 33 PSI in my 35-in tires

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Texas… probably not quite the same as the slippery forest roads (mossy rocks and moist tree roots) here in the PNW.

Ratbert said:

I'm no fan of mud, but wouldn't more surface area make you more likely to ride on top of it instead of less?

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I found the opposite actually.

I guess it depends what kind of mud you're in. But I find if you're trying to ride on the mud, AT tires at full inflation tend to ride better on top of the mud without breaking the surface. If you're in MT tires and you're trying to run on top of the mud, it tends to just dig in and if there was any hard layer on top, not anymore if you're riding with MT's.

If you're in that soupy shit, MT tires with full inflation seem to work best, same way all the side by sides that live in that shit run it.

Albeit with rock crawling, an MT tire with low PSI has the most grip, but it also becomes a question of do you need it?

Outside of MT tires on beadlock Wheels with very low psi, 10 or less have a tendency to hug the rock. Throw in some competition rubber and you've got a guaranteed Rock crawler. However if you have big enough lugs that are wide enough space, even at full PSI, you should still have plenty of grip to make it up majority of obstacles.

Just what I've noticed from the tires I've owned in the last 3 years.

Tredsdert said:

Different kind of driving, I understand, but look at them tires...



Same thing here, I get they all have 40"+ tires, but ain't none of them aired down...

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Some of the ATVs in the first video are aired down. The others are blindly bashing against the rocks at speed, so they want as much rubber between their wheels and rocks as possible. Nothing will last long when being (ab)used like that. The laws of physics hurt.

Unless I'm missing something, the rigs in the second video look pretty damn foolish. Look at the minimal surface area those fully-inflated tires have while cresting those rocks and consider how much more grip they'd have if they were aired down. Maybe they think it's a sign of their manliness or something stupid like that?

I answered "always", even though obviously I don't bother if I'm only going a very short distance off-road and it's mild terrain.

But if I'm going off-road for more than a mile or two, I always air down, every time. Even if for no other reason than to make the ride softer.

My air-down / air up system is so fast and easy to use, I really don't mind doing it frequently. I actually kind of enjoy it.

For air-down I use Staun deflators, which are set to 14psi. Just screw them on and let them do their job, you don't even have to wait for them to finish if you don't want to, you can still drive while they're letting air out, and just take them off whenever they're done.

For airing up, I use a MORRflate compressor and 4-tire system. The compressor is permanently wired in and mounted in the cargo area, so I just connect the chucks to the tires, flip the On switch, and wait 5 minutes or so while it airs up.

Tredsdert said:

Albeit with rock crawling, an MT tire with low PSI has the most grip, but it also becomes a question of do you need it?

Outside of MT tires on beadlock Wheels with very low psi, 10 or less have a tendency to hug the rock. Throw in some competition rubber and you've got a guaranteed Rock crawler. However if you have big enough lugs that are wide enough space, even at full PSI, you should still have plenty of grip to make it up majority of obstacles.

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I don't want to be swapping out AT / MT tires when the weather changes, so MTs aren't really an option / make sense for me. Note that I avoid mud and live / trail where mud is rarely a concern.

That being said, to get the traction required to do the obstacles that I love doing (those that require planning and possibly multiple attempts) I have to air down. The winch is always available as a backup strategy when my brain plus tires can't finish the task. At some point the "Colorado bump" plus endlessly burning the rubber off the tires just doesn't cut it.

My default pressure is 14 to 15 psi. If I'm doing something more extreme (~level 6+) then I'll drop them to 12. That's just 37s on standard AEV wheels. No beadlocks.

@Tredsdert, have you tried rock crawling with street pressures, then aired down to compare the difference? You might become a convert once you try it

I only air down on the rough trails, if I don't it bounces me around like a BB in a beer can. I always disconnect my sway bar links.

A few times I decided not to air down because it wasn't necessary. But each time I regretted it because the ride was so rough. I now always air down for comfort, then adjust the pressure based on expected obstacles. In my case (37s w/o beadlocks) I found 16 psi is great for most dirt roads, 12-14 for general trails, 10-12 for rocks, and 8-10 for snow (might have to lower this more in deeper snow).

I also consider ground clearance. But around 12 psi the tire still looks round except when transferring weight to one or two tires (e.g. rear tires when climbing a steep obstacle).