BajaNomad

Tire deflation for sand

alafrontera - 2-17-2010 at 06:10 PM

In another thread people talk about deflating tires to 26/ 20 even 10 psi. OK I could experiment with that. On Monday I looked like the classic idiot gringo stuck in the sand, really gotta hate that.

My question is; do you have a recomended pump for re-inflation? I assume these can be bought at Pep Boys or = ? Any particular brand or specs to look for?

Vehicle is a Chevy Astro van, allegedly AWD. Hah. Only wheel spinning was the left rear.

Edit: I might add that the van fully loaded is pretty heavy if that makes a difference.

And here I was doing so well impressing the g/f too. :mad:

[Edited on 2-18-2010 by alafrontera]

BajaWarrior - 2-17-2010 at 06:20 PM

Depending on the tire size as well, but I'll guess a 234/75/R15. On that size vehicle even loaded I would go about 15. It would be nice if the AWD was cooperation too...

John M - 2-17-2010 at 06:24 PM

Hey Alafrontera -

Ain't diggin' out a part of the adventure?

How low can you go with air pressure? If you are not yet stuck and in soft sand, I'd start with 15 to 16 lbs. and work your way down from there. Stuck? The depths of the earth is the limit, I've been as low as 6 to 8 pounds in really soft stuff, but a mid-range of 12 to 14 seems reasonable.

Then to refill the tire.....

Tons of choices and as usual it depends on the size of your wallet.

The compressor I now use is this by Viair
http://www.viaircorp.com/OffRoad/400P.html

Copy and paste the link if necessary. But, it is pricey - around $250+ if you shop around, and for my use it is a worthwhile investment. Maybe way overkill for your needs.

Someone makes a hose that connects between your spare tire and the "flat" tire and the idea is that the hose will equalize tire pressures so you'd have enough pressure to make it somewhere. I'd expect it is pretty inexpensive.

Pep Boys and other places sell compressors that will suffice the once-in-a-while situation - they don't pump up tires nearly as quickly but will get the job done.

Many here have the less expensive versions as their primary source of air or as a back up in case the $$$$$ version takes a dump.

John M

[Edited on 2-18-2010 by John M]

bkbend - 2-17-2010 at 06:43 PM

If you do go with one of the lower priced alternatives, be aware they will take a while to air up and they will get very hot. Heat kills the pump and many will have an auto shut-off. What I usually do is pump up to the minimum needed for pavement and head for the nearest llanteria to top off. You usually don't need to go far to find one.

Donjulio - 2-17-2010 at 07:04 PM

Quote:
Originally posted by alafrontera


And here I was doing so well impressing the g/f too. :mad:

[Edited on 2-18-2010 by alafrontera]



First mistake was an Astro Van :lol::lol::lol:

alafrontera - 2-17-2010 at 07:51 PM

No no, the van was a hit. Very comfy. Getting stuck, otoh, was a tad embarrasing.

dtbushpilot - 2-17-2010 at 08:11 PM

When the fuse in my inexpensive cigarette lighter powered compressor blew I wrapped the fuse in a foil gum wrapper and re-installed it....problem solved......dt

roadhog - 2-17-2010 at 08:24 PM

Experience in Florida sugar sand:
buy a floor jack with a low lift pad - see Clark jacks at Summit Racing - hammer 2x4 on plywood for jack support pad and for raising/shimming the jack the necessary effective height to jack your truck. The low height lift pad used when the truck digs in.
Buy a carpet runner. Home Depot may have runnners in stock. A good 'contract carpet' for commercial areas. Place the runnner under the drive tire or two if you had the forethought into LSD, and drive off. A heavy vehicle may use more runner reinforcement - 2x2 slats, concrete reinforcing mesh, chicken wire.... like something you'd be rummaging in the bushes for ! A nice blanket from the thrift folded and stowed into a garbage bag then tucked into the odd corner to lie on makes the day.
Pass the Molson's

Barry A. - 2-17-2010 at 08:32 PM

For reinflation, I use a QUICKAIR II---------really fast, and rugged. Pricey, too. (over $200)

From experience, the cheapo's can take up to an hour to inflate 4 big tires---if it lasts that long (very iffy) before it burns up.

I will stick with the pricey one.

works for me.

landyacht318 - 2-17-2010 at 08:43 PM

http://www.amazon.com/Master-Flow-MF-1050-Portable-Compressor/dp/B000L9AD2U


While the Viair is the mac daddy of 12 volt air compressors, I've been using this one for years. It is a knock off of the viair.

It has alligator clips to attach directly to the battery. It pulls about 18 amps according to my battery monitor.

It pumps my 4 235/75 15s from 32 to 50psi in about 20 minutes. It gets warm. I've used it a lot.

It comes with an air filter, which makes it a little quieter as well. Be sure to remove the plastic flashing from it's intake holes to increase the flow.

It is rated for 12 upto 13.5 volts dc. The only bad things I've read about it are by those who have burnt them up inflating huge tires on multiple vehicles, while the engine is running.

A vehicle's engine while idling can produce upto 14.7 volts or more, so this might be a reason why they can burn up.

bajalou - 2-17-2010 at 10:06 PM

I've used a similar unit for several years also with no problems - gets a little warm pumping up 4 33-12.50-15s but doesn't really take much time. Way better than the smaller ones I had used before. Mine from Harbor Freight - catch it on sale for about $49.

roadhog - 2-18-2010 at 08:22 AM

http://www.duneguide.com/ProductReview_SandMats.htm

David K - 2-18-2010 at 08:35 AM

Ala, I bumped up an older thread on air compressors (Nomad search works great, by-the-way)...

I have the one Lou has, after he told me... in 2007... Here is a blip from my Feb. 2007 trip report:

"Leaving the 'island' we once again had to ford the flooded access road, which was no problem with the Tacoma, and Cooper tires. Once out of the mud and water, I re-inflated the tires using my super new air pump from Harbor Freight. A big thanks to ‘bajalou’ for telling me about this fast, quiet and inexpensive tire pump!

It is a Central Pneumatic 12 volt High Volume Air Compressor Item 93186, under $50. See photo… From 10 psi to 40 psi at a rate of 6 psi per minute. The cigarette lighter powered air compressors I have had before would only deliver 2 psi per minute."

Photos on that report include one of the pump at work:
http://forums.bajanomad.com/viewthread.php?tid=22837

David K - 2-18-2010 at 08:41 AM

Oh, for where to go with pressure if you are already stuck?

Go to 10 psi (have a good gauge that reads low pressure).

Clear away sand from the tires... it will act like a block, otherwise.

Clear sand from under the van if it is that low... usually the differential will be blocked if burried.

Even better, pour some water (have a bucket in Baja, always) in the sand in the direction you are going to drive out.

Ease on out, do not spin the tires (why limited slip differentials work so well in sand)... If it doesn't float after moving out of the stuck... drop air to 8 psi. However, do not turn the tires abruptly until re-aired.

David K - 2-18-2010 at 08:44 AM

Quote:
Originally posted by landyacht318
http://www.amazon.com/Master-Flow-MF-1050-Portable-Compressor/dp/B000L9AD2U


While the Viair is the mac daddy of 12 volt air compressors, I've been using this one for years. It is a knock off of the viair.

It has alligator clips to attach directly to the battery. It pulls about 18 amps according to my battery monitor.

It pumps my 4 235/75 15s from 32 to 50psi in about 20 minutes. It gets warm. I've used it a lot.

It comes with an air filter, which makes it a little quieter as well. Be sure to remove the plastic flashing from it's intake holes to increase the flow.

It is rated for 12 upto 13.5 volts dc. The only bad things I've read about it are by those who have burnt them up inflating huge tires on multiple vehicles, while the engine is running.

A vehicle's engine while idling can produce upto 14.7 volts or more, so this might be a reason why they can burn up.


This looks like the one Doug sells here on Baja Nomad...

http://tienda.bajanomad.com/index.php?act=viewProd&produ...

Bwana_John - 2-18-2010 at 08:58 AM

I usually have Scuba tanks, I use the air left over from diving to reinflate my tires.

Using a small 50cf tank and 285-75-R16 tires, 125psi/tank=10psi/tire

Cyanide41 - 2-18-2010 at 05:30 PM

I use the same knock off as landyacht318. I got mine at costco for $50. I typically deflate to 14lbs using preset tire deflators. I have heard of people going as low as 5lbs, but you have to be careful not to spin the tires off the rim or breaking the bead at that PSI. I am also using 35x12.5 R17 tires, so the width helps.

The reason your 1 tire was spinning was because it was the one with the least resistance. What you would need is a locker, which forces all of the tires to spin together. You would need one for both differentials. I would be surprised to learn the made lockers for an astro van.

BooJumMan - 2-19-2010 at 09:32 AM

The MV50 (Pictured above in this thread) is what a lot of the offroad guys use to pump up their tires. These things are dirt cheap, and put out a lot of cubic feet per minute. I bought mine at Pepboys and routed it to a air tank. They are completely portable from the box though..

Definetly worth it. Yes, and if you deflate your tires under 15, then make sure you don't spin them fast or else you'll have a good chance of popping a bead.

baitcast - 2-19-2010 at 01:08 PM

ah yes chevy astro van awd made three trips down in mine,brand new 204 the following are some of the problems I had I only mention this to make you aware of possible problems.

Worked fine in the sand for me but all four shocks went south after the third trip,fuel pump crapped out,water pump leak,emission problems,I loved the rig but it could have got me into big trouble in the waste lands all this and only 25000 miles:rolleyes:.......careful!!!!!!!!
Rob

[Edited on 2-19-2010 by baitcast]

David K - 2-19-2010 at 03:32 PM

Baitcast, that is called ''that great GM feeling''!:biggrin: