Good morning! I have a stupid new guy question. There are several threads about tire pressures and portable pumps and guess I'm trying to figure out when others air down their tires. It's obvious that tire pressure needs to be reduced for sand and mud, but what other times do you let air out and for what reasons? Does anyone have a general rule of thumb?
Stupid question: Airing down tires
- Thread starter jha6av8r
- Start date
highz
Retreaded
When your kidneys hurt and your teeth rattle in your head
So much depends on your individual rig and the tires you have. I'm not a hard core off-roader, so I don't have to air down all that often. When the Forest Service Roads I drive get rocky and unmaintained, the rig tells me to air down to smooth things out a bit.
So much depends on your individual rig and the tires you have. I'm not a hard core off-roader, so I don't have to air down all that often. When the Forest Service Roads I drive get rocky and unmaintained, the rig tells me to air down to smooth things out a bit.
Overland Hadley
Contributors
When your kidneys hurt and your teeth rattle in your head
So much depends on your individual rig and the tires you have. I'm not a hard core off-roader, so I don't have to air down all that often. When the Forest Service Roads I drive get rocky and unmaintained, the rig tells me to air down to smooth things out a bit.
Good explanation.
I air down for extended times in sand/mud, or when the road is rough with fist sized and larger rocks, or when the corrugations are bouncing my eyes.
Just remember to go slower when aired down. I usually air down to 25-30psi and keep the speed under 40mph. If you are under 18-20psi you should not really go over 10mph. Those are not rules, just a rough idea.
So much depends on your individual rig and the tires you have. I'm not a hard core off-roader, so I don't have to air down all that often. When the Forest Service Roads I drive get rocky and unmaintained, the rig tells me to air down to smooth things out a bit.
Good explanation.
I air down for extended times in sand/mud, or when the road is rough with fist sized and larger rocks, or when the corrugations are bouncing my eyes.
Just remember to go slower when aired down. I usually air down to 25-30psi and keep the speed under 40mph. If you are under 18-20psi you should not really go over 10mph. Those are not rules, just a rough idea.
Overland Hadley
Contributors
So airing down for other than mud or sand is really more of comfort issue?
Well, there might be an argument that airing down a little over sharp rocks will help your tires. But I am not sure how that argument would go. In off road racing you would adjust the tire pressure to the conditions, but that would have little to do with us overlanders.
I do know that when I mountain bike I get a lot more flat tires when I ride trails with my tires at full pressure. Would the same apply to a trucks tires, probably.
This would be a good point for ntsqd to jump in and explain....
Well, there might be an argument that airing down a little over sharp rocks will help your tires. But I am not sure how that argument would go. In off road racing you would adjust the tire pressure to the conditions, but that would have little to do with us overlanders.
I do know that when I mountain bike I get a lot more flat tires when I ride trails with my tires at full pressure. Would the same apply to a trucks tires, probably.
This would be a good point for ntsqd to jump in and explain....
Well, there might be an argument that airing down a little over sharp rocks will help your tires. But I am not sure how that argument would go. In off road racing you would adjust the tire pressure to the conditions, but that would have little to do with us overlanders.
I do know that when I mountain bike I get a lot more flat tires when I ride trails with my tires at full pressure. Would the same apply to a trucks tires, probably.
This would be a good point for ntsqd to jump in and explain....
That makes sense for going over a lot of sharp rocks or if you're trying to go fast(er) over washboard roads. Wanted to make sure I wasn't missing something that I absolutely needed to do. Love the discussions and the knowledge on this site and as it seems with most anything, you have to find what works for you and your rig. Thanks for the answers so far.
I do know that when I mountain bike I get a lot more flat tires when I ride trails with my tires at full pressure. Would the same apply to a trucks tires, probably.
This would be a good point for ntsqd to jump in and explain....
That makes sense for going over a lot of sharp rocks or if you're trying to go fast(er) over washboard roads. Wanted to make sure I wasn't missing something that I absolutely needed to do. Love the discussions and the knowledge on this site and as it seems with most anything, you have to find what works for you and your rig. Thanks for the answers so far.
chnlisle
Post Master
My understanding is that the biggest reason to air down would be to increase traction in sand , snow, rocks, dirt etc. I've heard some go down as low as 15 pounds but that seems pretty low to me. Especially if you don't have bead locks. Another reason is to give a more comfortable ride on rough back roads. We usually air down to abut 28 but I have E rated tires and a 3/4 ton truck. I no longer use my old BFG A/T's and now run street tires. I get much better fuel economy especially with 65 pounds in the tires. And for the 4 or 5 times a year I'm on back roads, dirt roads and the like the street tires work just fine.
Rotti... Was this a Michelin LTX AT2?
No, it was a Firestone Wilderness something or another. It was on my Tahoe with only 24,0000 miles. Gravel roads hate me.
As far as airing down I never have....too lazy I guess. My thought, I guess is, if that little compressor doesn't work then I might have to drive a long way on severely under inflated tires. Plus with our 3/4 or 1 ton trucks and the 70 psi tires it could kill those pumps fairly fast. Mine has worked fine in the driveway though.
The only time I debated airing down was in the Great Sand Dunes NP. Sand is probably where you definitely should air down but I plowed on through without too much drama. It did get my attention though....like deep snow. (I'm a sand virgin)
No, it was a Firestone Wilderness something or another. It was on my Tahoe with only 24,0000 miles. Gravel roads hate me.
As far as airing down I never have....too lazy I guess. My thought, I guess is, if that little compressor doesn't work then I might have to drive a long way on severely under inflated tires. Plus with our 3/4 or 1 ton trucks and the 70 psi tires it could kill those pumps fairly fast. Mine has worked fine in the driveway though.
The only time I debated airing down was in the Great Sand Dunes NP. Sand is probably where you definitely should air down but I plowed on through without too much drama. It did get my attention though....like deep snow. (I'm a sand virgin)
Overland Hadley
Contributors
I've heard some go down as low as 15 pounds but that seems pretty low to me.
Saw somebody with a Suzuki that ran 0psi! They did not even have valve cores in.
Like you said it all depends on the rig.
Saw somebody with a Suzuki that ran 0psi! They did not even have valve cores in.
Like you said it all depends on the rig.
http://www.offroadadventures.com/articles/view/id/509
Maybe these guys are a better source of pertinent information than myself.
Maybe these guys are a better source of pertinent information than myself.
craig333
Riley's Human
It makes a big difference in traction yes but, for the most part I don't do trails in my truck that require that much extra traction. Jeep yes. Jeep I'll air down to 8 psi in the rocks but it goes places my truck never will. If you haven't aired down for comfort you'll be surprised just how much it helps. All that said, I rarely air down my truck. I just don't normally feel the need. It has a lot to do with distance also. I don't mind some jarring if its a short distance. If its a long distance over washboard roads then its definitely worthwhile.
How much to air down? All depends on your tires, how much you weigh, comfort or traction desired and other factors. I tend to air down until I see the tires showing a slight bulge. I'll be more conservative on the truck than the Jeep. The Jeep is much easier to change a tire on if lose a bead.
How much to air down? All depends on your tires, how much you weigh, comfort or traction desired and other factors. I tend to air down until I see the tires showing a slight bulge. I'll be more conservative on the truck than the Jeep. The Jeep is much easier to change a tire on if lose a bead.
generubin
Electric Baja
Long washboard roads I always air down. It makes things more comfortable, decreases impact to the suspension, and reduces the chances of a sharp rock through the tread. Think of a balloon; if you blow it up to its near limits, a pencil will pop it immediately, if you blow a balloon up 3/4 of the way, the pencil can push into and deform the balloon but will not pop it.
I used to know this fellow from Alaska, with no desert smarts (actually he wasn't too bright about anything). He'd berate any advice I'd offer, he'd insist on running higher than normal tire pressures on washboard with his BFG's. Now, I have done well over 100 trips into Saline on world class washboard and sharp rocks without a single flat. This dude from Alaska would get 1 to 3 flats with every trip into Saline. Finally, he took my advice and his flat tires came to a stop. I could tell you more chilling stories about this guy but just thinking about him gives me the creeps (Jay knows what I'm talkin' about), the dude actually left dead and maimed people in his wake, almost included my son.
I used to know this fellow from Alaska, with no desert smarts (actually he wasn't too bright about anything). He'd berate any advice I'd offer, he'd insist on running higher than normal tire pressures on washboard with his BFG's. Now, I have done well over 100 trips into Saline on world class washboard and sharp rocks without a single flat. This dude from Alaska would get 1 to 3 flats with every trip into Saline. Finally, he took my advice and his flat tires came to a stop. I could tell you more chilling stories about this guy but just thinking about him gives me the creeps (Jay knows what I'm talkin' about), the dude actually left dead and maimed people in his wake, almost included my son.
JHanson
Senior Member
John,
Airing down does have advantages in terrain other than soft sand or mud. Moderate reduction in tire pressure increases traction on hilly dirt trails, and reduces trail erosion by reducing wheel spin. Reducing wheel spin benefits your tires and drivetrain - it's a cascading effect. The added comfort is really a side benefit.
In soft sand airing down will move your vehicle into a different universe of capability. The tire footprint lengthens (this, rather than widening, is the main gain), greatly increasing its flotation. Time and time again I've demonstrated driving into dune-type sand at full street pressure, immediately bogging down, then reducing tire pressure to 15 psi and driving right on out. With a fully loaded camper you'd adjust this upward, but at one bar (14.7 psi) or above there's scant risk of losing the bead.
You do need a proper compressor for this, which should be high on your list of standard equipment anyway.
Airing down does have advantages in terrain other than soft sand or mud. Moderate reduction in tire pressure increases traction on hilly dirt trails, and reduces trail erosion by reducing wheel spin. Reducing wheel spin benefits your tires and drivetrain - it's a cascading effect. The added comfort is really a side benefit.
In soft sand airing down will move your vehicle into a different universe of capability. The tire footprint lengthens (this, rather than widening, is the main gain), greatly increasing its flotation. Time and time again I've demonstrated driving into dune-type sand at full street pressure, immediately bogging down, then reducing tire pressure to 15 psi and driving right on out. With a fully loaded camper you'd adjust this upward, but at one bar (14.7 psi) or above there's scant risk of losing the bead.
You do need a proper compressor for this, which should be high on your list of standard equipment anyway.
ntsqd
Custom User Title
On my Toyota Mini-Truck with 33-10.50 tires I rarely go below 19 psi, and run 30 psi on the street. Experience has shown there's no need to go lower with that particular combo in where I go. With the 'glass dune buggy my street pressure was 10 psi. When we got into really, really soft stuff I'd go clear down to 8 psi (I think that I did that twice in nearly 20 years). I know a guy who routinely runs his Sami on 35's w/o the valve stem cores in. He goes into a lot gnarlier trails (Rubicon, Hammer's, etc.) than I do. He also runs a tire that I would never, ever run on pavement (one of the ungodly heavy Super Swamper variants).
Even though I can't wrap it in a scientific explanation my rule of thumb is full pressure if I'm going fast, lower pressure if I'm going slower. The exception is long washboard (Saline, El Arco, Barcroft Station, etc.). Again, experience has shown me (desert races over the last 1.5 decades, Baja, NV/OR Great Basin, Mojave Desert, etc.) that this is what works for me. I make no claim that it will work for anyone else. I don't even, yet, know if it will work for the CTD as I don't yet have enough experience with it to know for sure. I suspect that it will, mostly because going fast is hard on equipment and we'll be going slower since I've no desire to beat up the camper.
Even though I can't wrap it in a scientific explanation my rule of thumb is full pressure if I'm going fast, lower pressure if I'm going slower. The exception is long washboard (Saline, El Arco, Barcroft Station, etc.). Again, experience has shown me (desert races over the last 1.5 decades, Baja, NV/OR Great Basin, Mojave Desert, etc.) that this is what works for me. I make no claim that it will work for anyone else. I don't even, yet, know if it will work for the CTD as I don't yet have enough experience with it to know for sure. I suspect that it will, mostly because going fast is hard on equipment and we'll be going slower since I've no desire to beat up the camper.
Thanks for the additional comments. The decision to air down obviously leads to the next question airing back up. I'm at about 9,500 lbs loaded and I don't want to run long distances on the freeway with low tire pressure. Normally I'd run 80 psi in the rears and 60 psi in the front. I saw a post about the MV-50 pump. The comments have been mixed on its reliability. What are others using?
generubin
Electric Baja
I use the Vi-Air 400 which was around $300 when I bought it many years ago. Prices are lower now, less than $200: http://expeditionoffroad.com/4x4_parts/air_systems/compressors/viair_400p_portable_compressor
The MV50 might be just fine at $60. I'm just usually leery about going to too cheap on an important tool such as this.
The MV50 might be just fine at $60. I'm just usually leery about going to too cheap on an important tool such as this.
I use the Vi-Air 400 which was around $300 when I bought it many years ago. Prices are lower now, less than $200: http://expeditionoffroad.com/4x4_parts/air_systems/compressors/viair_400p_portable_compressor
The MV50 might be just fine at $60. I'm just usually leery about going to too cheap on an important tool such as this.
I agree.
The MV50 might be just fine at $60. I'm just usually leery about going to too cheap on an important tool such as this.
I agree.
Overland Hadley
Contributors
Here is a place to start. http://www.sierraexpeditions.com/index.php?l=product_list&c=103 You will not regret buying a good air compressor.
I went with an ExpeditionAire from Extremeaire. I liked the fact that it has two air compressors working together. One goes bad I still have one going.
I went with an ExpeditionAire from Extremeaire. I liked the fact that it has two air compressors working together. One goes bad I still have one going.
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