Airing tires down

[6.2Blazer]

My first comment is to do some experimenting on tire pressure....and verify you really "need" to air down in certain circumstances. Yes, airing down tires helps off-road in most situations especially in soft sand but is not always "needed" to get around. I've been trail riding for 20+ years with aired down tires in certain situations simply depending on the need based on the terrain and trail difficulty. Again, airing down "helps" but is offset by the time and effort to air down and then air back up versus if you are actually struggling or having traction problems on the trail. Same goes for the beach....there are some circumstances you may not really need to air down to traverse the sand. The nice thing about this is if you start struggling you can stop before digging in and air down the tires as needed.

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[Murphydog]

Prior to my Jeep I had never aired down. Most of my adventures were rough forest service roads in a 4X4 truck, both mid and full sized. We had rented Barlow Jeeps in Sedona and those were always set at about 20 PSI.

Of course for our trip to Moab we aired down as well. Besides the traction improvements airing down can smooth out the ride too. We covered several sections of rocks that could be called "baby heads" - think Schneblly Hill road in Sedona. With the tires aired down and the sway bar disconnected the ride is much better. My Ram 1500 4x4 had more than enough clearance for this type of road, but the ride was punishing - felt like I was going to hit my head on the side window if I wasn't careful. In the Jeep with the tires aired down and the swaybar disconnected the ride was tolerable.

In terms of compressors - I really like the Viair. The quality is very good, easy to use and does the job efficiently. I snagged mine on sale at Amazon for less that $175. If I was able to hit the trails more frequently, I would consider one of the onboard solutions.

 

[Old Jeeper]

Jeep newbie here. I've always wanted a jeep and finally got one! Super excited to take it out on the beach and some back country trails. I have been reading that I should air the tires down to around 15 Lb for the sand. I'm not sure how to do that and what do you use to air them back up with? I want to do it as simply as possible. Thanks in advance for any helpful tips you may have.

I would hesitate to aire down to 15 lbs. The last thing you want is to peel your tire off the rim and Sand is not your friend. I would go 25 and look at your contact patch, if all looks ok, try 20..


Contact patch can be done using chalk, dust on a dirt road or driveway, or a then rain puddle.

Here are the rear tires on my F 450 Dually, note the BLACK and the White. Black is wet, white is dry, and over-inflated is what you are seeing , so I dropped down 2 psi at a time until I got a full contact patch.

I drive thru a light rain that barely left any wet spots. you can do the same in your driveway and a water hose. Dust or chalk will give the same results.

Lot of good air compressors out there, but I like these and have run them for years, not cheap, but serious psi and reliability.

https://www.extremeoutback.com/

 

[Jillybean1]

I would hesitate to aire down to 15 lbs. The last thing you want is to peel your tire off the rim and Sand is not your friend. I would go 25 and look at your contact patch, if all looks ok, try 20..


Contact patch can be done using chalk, dust on a dirt road or driveway, or a then rain puddle.

Here are the rear tires on my F 450 Dually, note the BLACK and the White. Black is wet, white is dry, and over-inflated is what you are seeing , so I dropped down 2 psi at a time until I got a full contact patch.

I drive thru a light rain that barely left any wet spots. you can do the same in your driveway and a water hose. Dust or chalk will give the same results.

Thank you Don! This was very helpful.

 

[GrayWolf.Overland]

https://www.amazon.com/dp/B01M0L7JS2/ - get one of these. best $35 investment ever.. I have this set and still works well after 1.5 years. I have set them up for 20psi.

 

[txj2go]

I would hesitate to aire down to 15 lbs. The last thing you want is to peel your tire off the rim

You can do more research here but I've read that 16psi is safe with factory Rubicon tires. I generally shoot for 20 or a little bit less. If my tires are at 36-38 for highway than 2 minutes and fifteen seconds with my key will get them down to just under 20. Then the same amount of time with my pump gets them back up to highway pressure. After doing that a couple of times on a trip the individual pressures will vary by 5 psi or more so when I get home I have to get the big compressor out and even them up.

 

[Jillybean1]

https://www.amazon.com/dp/B01M0L7JS2/ - get one of these. best $35 investment ever.. I have this set and still works well after 1.5 years. I have set them up for 20psi.

Great to know. Just placed my order. Thanks!

 

[Zandcwhite]

My first comment is to do some experimenting on tire pressure....and verify you really "need" to air down in certain circumstances. Yes, airing down tires helps off-road in most situations especially in soft sand but is not always "needed" to get around. I've been trail riding for 20+ years with aired down tires in certain situations simply depending on the need based on the terrain and trail difficulty. Again, airing down "helps" but is offset by the time and effort to air down and then air back up versus if you are actually struggling or having traction problems on the trail. Same goes for the beach....there are some circumstances you may not really need to air down to traverse the sand. The nice thing about this is if you start struggling you can stop before digging in and air down the tires as needed.

In my opinion, airing down in most situations is more about ride comfort than traction (The same reason I disconnect the sway bar every time we go off road regardless of the need for articulation). Wash board roads in the desert are rarely lacking for traction, but rolling over them at 15psi sure is a lot more pleasant. Obviously if I’m just driving 10 minutes down a dirt road, the time isn’t worth the effort. If I’m traveling multiple hours down even a simple graded dirt road, the increased speed I can travel thanks to the comfort factor is going to save me time even with the air down and up time. I’d rather drive home at freeway speeds at 20psi than wheel for hours at 30psi, but to each his own.

 

[Jillybean1]

In my opinion, airing down in most situations is more about ride comfort than traction (The same reason I disconnect the sway bar every time we go off road regardless of the need for articulation). Wash board roads in the desert are rarely lacking for traction, but rolling over them at 15psi sure is a lot more pleasant. Obviously if I’m just driving 10 minutes down a dirt road, the time isn’t worth the effort. If I’m traveling multiple hours down even a simple graded dirt road, the increased speed I can travel thanks to the comfort factor is going to save me time even with the air down and up time. I’d rather drive home at freeway speeds at 20psi than wheel for hours at 30psi, but to each his own.

 

[Jillybean1]

You have all been so kind in sharing so much information! The education you are giving me is greatly appreciated!!

 

[lashlee]

Like someone else noted, I started with one of the ARB deflator kits. My best friend has the Apex valves and can air down four 40" tires in the same time that I can air down one 37" tire. I've since swapped out the valve stems for the Apex ones, and will never look back.

I run a non beadlock wheel with 37's and have no issue running 15 psi. I wheel out at Windrock park with lots of rocks and mud so don't be afraid to lower down into the 15-20 psi. It's only about a 20 minute ride home so I don't air back up until I get home.

 

[entropy]

I run stock rubi tires/wheels. The M/T falken set. I run 12~15psi. Usually 12. I've never had any issues and I've been wheeling like that over a dozen times.

 

[Old Jeeper]

I run stock rubi tires/wheels. The M/T falken set. I run 12~15psi. Usually 12. I've never had any issues and I've been wheeling like that over a dozen times.

Deeper Dive: CoT, Coefficient of Traction. We have 3 common grounds we wheel on. Sand, Mud-dirt and rocks. I can say most of my wheeling time was mud-dirt due to where I lived that was all there was play in. Then I discovered rocks and I have been doing that for 20+ years. Rocks demand Beadlocks if you get really serious. Mud-Dirt and Sand are more forgiving when it comes to your CoT as it offers more give vs the hard surface of rocks.

Airing down: Yes you gain a bit of comfort, but the real gain for the rock folks is it increases the size of the contact patch. Depending up the make of the tire and its intended use, its internal architecture you can increase the size of the contact patch as much as 25% and now you are airing down where I play at 3-5 psi and now you know why I have beadlocks.

I will admit that once and only once have I ever peeled a tire and with luck and my On Board Air I was able to reseat without any issues. How psi was I running? 15 psi. I know why I peeled the tire, it was because I got into a wedge and was trying to drive up and over. The up side was a rock face and the bottom was dirt. I was not doing well getting up and over and I hammered to hard and it was the rock side that peeled it off.

As a rock guy my go-to tire is the BFG KM2. I had run GY MTRs for several years. One of my wheeling buddies was a guy who worked in the HQ of Discount Tire. He called me up one day and said I got a new set of tires from BFG, the KM2, I would like for to try a set and see what think. So I threw them on my Walker Evans Beadlocks and headed out to Table Mesa N of Phoenix and WOW was I impressed they clearly outperformed my MTRs, which was a great tire. The next day was Saturday and I called up some buddies and we hooked up and took an all new trail to me they called it the Shale Trail. It was a creek bed with lots of rocks and shale. Very challenging and those KM2s I had were the only tire that stood up to the Shale. In fact, I was the only one who did not slice a tire open that day.

This is in front of my shop, the red Jeep bottom left has the BFG KM2 mounted on it. It is at 16-18 psi for the street, 3-5 psi for the rocks

 

[Old Jeeper]

https://www.amazon.com/dp/B01M0L7JS2/ - get one of these. best $35 investment ever.. I have this set and still works well after 1.5 years. I have set them up for 20psi.

I had those, in fact bought a set then won a set in a raffle. They work and work very well...

 

[Old Jeeper]

You can do more research here but I've read that 16psi is safe with factory Rubicon tires. I generally shoot for 20 or a little bit less. If my tires are at 36-38 for highway than 2 minutes and fifteen seconds with my key will get them down to just under 20. Then the same amount of time with my pump gets them back up to highway pressure. After doing that a couple of times on a trip the individual pressures will vary by 5 psi or more so when I get home I have to get the big compressor out and even them up.

Its not a question of Safe, unless you are driving at high speeds.

Its really the bug-a-boo of Torque vs Traction. Mud, dry sand, dirt are one thing. Too much applied torque generally ends up with a spinning tire, no more, no less. Now apply the same torque on the rocks you can peel a tire off the rim in a heartbeat.

Take a look at this pic: Going down was pucker, due to the drop off on the right, but going back up and over was a challenge. You would make with big traction and the application of some good torque. Look at the left rear tire, these are GY MTRs and they did like the DOWN low psi of my BFG KM2s (3-5 psi). I ran my MTRs around 6-8 psi and on the street was running about 22 vs the 16 on my KM2s. This is a result of the internal design. Its my thinking the KM2 has a bit stiffer sidewall because at 3-5 my sidewall was not folded like on my MTRs.

Its like a shoe, some shoes are for running some for walking...wear the right shoe at the right time.

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