BajaNomad - The limits of 4 wheel drive......

The limits of 4 wheel drive......

surfer jim - 1-16-2006 at 09:53 AM

Took my new truck out to Lucerne Valley area Saturday.....Dodge 2500 4wd....wanted to see how it works....all stock.....BFG A/T 33 ".....front and rear lockers.....was playing in some sand hills...semi-hard packed....

found a slight sand hill several hundreds yards long ( that could be easily walked up)....

first try is 2 wd.....climbs up for a while but eventually slows and starts bouncing/chattering...end of climb

next try is 4 HI.....goes about one vehicle length further up

next 4 LOW......about same a 4 hi

next 4 low /w/rear locker....same again as 4 HI....

next 4LOW/w front and rear locker.....accually wouldn't go as far as 4 HI did !!....starts chattering/bouncing.....passenger goes out to see what's happening....tires turn/lose traction/get traction/ and this cycle continues....out of control...

All this was done with tires at probably 40 + PSI....(didn't bring guage ).....

Very shocked to find how little difference the 4wd added under this condition....even lockers no help.....

need to go back and experiment with tire pressure next......

elgatoloco - 1-16-2006 at 10:02 AM

It's all about tire pressure. :yes:

Bob H - 1-16-2006 at 11:43 AM

What motor do you have Jim?
Bob H

Ken Cooke - 1-16-2006 at 11:45 AM

With 40+ p.s.i. in your tires, you will have very little success in the sand in your pickup truck. Try airing down those tires to about 15 p.s.i. and maybe put a little weight in your pickup bed the next time you test in the sand. Before you go too far out, make sure you have a friend with a capable vehicle who can help you get unstuck. Carry a Hi-Lift Jack with a good Hi-Lift plastic base as well, a shovel, and maybe even a Pull-Pal to help you dig out. Remember, speed will also help you move above the sand.

Your ideal setup: 4 Hi - no lockers, 12 p.s.i., 25-35 m.p.h. - have a blast!! :bounce:

Ken Cooke - 1-16-2006 at 12:01 PM

btw, you can't walk up a sand hill. You have to run up it at a good amount of speed - If you know what is on the other side of this hill, you can stomp on the gas pedal and get about 40 m.p.h. until you crest the top of the sand hill. Going only 10 m.p.h. w/street pressure in your tires will bog you down and you'll go nowhere fast.

surfer jim - 1-16-2006 at 01:14 PM

This hill was MUCH harder packed than the photo above.....and no way near as steep.....noticed when driving on level sand in 2wd about 10-15 mph no problem...but stop slowly and try to go again ...no way.....

didn't bring tire guage with me but want to go back and start reducing pressure 5 psi at a time to see results......

I think I should go up this in 2wd with lower pressure......

And when I say "walk-up" I mean walking with legs ..... :lol:

Oh yes.....it's got a HEMI......

[Edited on 1-16-2006 by surfer jim]

Sharksbaja - 1-16-2006 at 01:30 PM

My best results in my hemi:

Deep sand 15- 20psi, under 30 mph....4wh low......over 30 mph....4wh high.
I usually drive the back roads in 4 wh high with 40 psi.
Get some gas shocks bro . If you get it lifted it becomes easier to crawl under when u have to dig yer way out! :lol:

Keep revs high and don't expect to "creep" around on soft deep sand....that's for sand rails and buggies.

I usually hold the trans in one gear (1st or 2nd)while ascending sand. If your truck auto upshifts on the way up the sand dune you may bog down and sink in.

What rear end does your truck have??

Ken Cooke - 1-16-2006 at 03:19 PM

http://www.staunproducts.com/

This is what you need!

Buy a set of these for ~$60 and set them at 20 p.s.i. Then, see if 20 p.s.i. allows you to drive in the sand properly. If not, drop the deflator setting to 15 p.s.i. and give it another try. This way, you can twist these deflators on each valve stem and wait for your tires to deflate.

When you need to drive out, you need this!
http://www.sunperformance.com/new_stuff.htm

David K - 1-16-2006 at 05:59 PM

You won't need a buddy along if you get stuck, just let more freakin' air OUT of your tires!

Nothing is harder to drive on than Shell Island or most of the gulf side beaches which contain 50% crushed shell along with the coarse sand... 20 PSI is the max. to get through, 10-15 psi is much better.

It's not about 4WD, lockers or horse power! I see locals driving their 2WD pickups on the beach south of San Felipe all the time... retrieving fish from nets, selling goods to gringos, whatever, they do it... all with low air pressure.

Some of you know Bob Hale who drives a BIG motorhome right out onto the beach at Shell Island... it is not 4WD... It is all AIR PRESSURE!

The lockers and low range 4WD are great for STEEP, rough grades where you need to crawl... Like the road into and out of Mision Santa Maria!

My old Subaru 4WD wagon with a 1600 cc motor and 13 inch tires did great on the beach... at 10 psi. It's not about power, low range just digs in more (too much power) than hi range as well.

It's all about the AIR PRESSURE... make those tires buldge and then they float on the sand!!! Heavy sidewall truck tires are not the best, as they barely buldge until almost flat.

The danger of running at low pressure is popping the bead on the front tires... So, no suddon turns or braking!

Also, you must reinflate once off the beach, dunes, or sand... as driving on underinflated tires will ruin the sidewalls and tires.

Okay, I'm done... :biggrin:

Bruce R Leech - 1-16-2006 at 06:34 PM

why is Co2 better than compressed air? I can get my dive tanks filled allot cheaper than buying Co2.

David K - 1-16-2006 at 06:36 PM

Yah, I though NITROGEN was the wonder gas for tires now!?? :lol:

Bruce R Leech - 1-16-2006 at 06:48 PM

if you use nitrous oxide you can have party time when it is time to deflate :lol:

Go to Costco...

Mexray - 1-16-2006 at 06:50 PM

...they use Nitrogen to fill your tires...no Oxygen to support rust on the inside of your steel rims...

Bob H - 1-16-2006 at 07:04 PM

Quote:

Originally posted by Mexray
...they use Nitrogen to fill your tires...no Oxygen to support rust on the inside of your steel rims...

Hey Ray, I remember you airing down at Shell Island - all four tires at one time. You should market that set-up!
Bob H

Bob...

Mexray - 1-16-2006 at 07:15 PM

I can't take credit for that one...I saw it on one of the Boards...the Big Bronco Board, I think. Someone had put together an article with pictures, etc...I made mine a bit different, but it was the same idea.

I have a small 12 volt compressor under the hood with a quick disconnect fitting and pressure Gage. My air down/up hose assembly is in the shape of an 'H' - with clip-on air chucks on the ends of the hoses, so I can hook all four tires up at one time (to the compressor) and air down/up them all with the same pressure to each, at one time. The only down side is my Vi air compressor...it takes a while to 'pump em' back up'. What I really need is something like:

http://www.powertank.com/start.htm

...and those 'shoes' would be filled in a real jiffy!

As to travel over the sand, its...

Mexray - 1-16-2006 at 07:31 PM

...flotation, flotation, flotation !

As said by others above, you've got to get your vehicle to 'float' over the surface of the sand - big, fat tires work great. Then if you have some real 'Hemi Power', you can put paddle tires on your rig and really FLY up those dunes! It's a delicate 'dance' between horse power and size of those fat tires.

Many years ago I built a sand buggy and powered it with rear engine Pinto Power! I picked up a junkyard stock 2100cc Pinto motor and hooked it up to a VW IRS tranny/suspension. I had to try several paddle tire sizes to get it to perform just right. I used that old Pinto motor for years...you just put your foot into it and up-shifted when the valves floated! Never could break that engine...and it had enough power to stop on the face of a dune, pop the ceramic clutch and 'burn' your way to the top again! Fun stuff, indeed!

Of course those were the days down at Pismo Beach before the State took over the beach and cut back on the fun! In those days, you could run down there on a three-day holiday and camp back in the dunes with 100's of your new best friends - and the noise and dune running would pretty much go on around the clock! Crazy days, but most everyone survived without 'Big Brother' and the State of Calif Park Ranger N-zi's looking over our shoulders! Goodbye Pizmo, Hello Baja California!

surfer jim - 1-16-2006 at 07:52 PM

shark....got 4:56....w/bilsteins.....

Roberto - 1-16-2006 at 08:11 PM

I use one of these:

and power it with a 1000 watt inverter permanently installed in the truck. Works great on my mud-terrain 37" tires, and it's less than $100. Inflates them right up!

[Edited on 1-17-2006 by Roberto]

Dave - 1-16-2006 at 08:17 PM

Quote:

Originally posted by David K
Yah, I though NITROGEN was the wonder gas for tires now!?? :lol:

Use can use propane. Just don't wind up with less that 10% in your tires. :saint:

ArvadaGeorge - 1-16-2006 at 08:44 PM

I got my RV stuck right off the bat in Campo Nuevo Mazatlan.
We had 2 atv?s & a Ford 4wd and did some digging and barely got it moving.
Javier cam along and pulled me out-with 2wd he had a full water tank in back.
Made me feel & look stupid..
He told me I needed 15 hp of air.
It?s hard to beat a guy in his own yard

surfer jim - 1-16-2006 at 08:49 PM

Ken C and Roberto bring up a good point...how to air UP... I didn't want to go down as no way to air up when done.....

DavidK....how do you air up after shell beach run?

Ken....how much does tank cost?...and how much does it air up (how many tires )

Roberto...does that run off of 120 ac or 12v dc?

I read somewhere about a PEP boy compressor....12v....for $30 that works good...anyone with experience or other 12 v dc compressor that gives good results?.....

[Edited on 1-17-2006 by surfer jim]

Neal Johns - 1-16-2006 at 09:09 PM

The best $40 or so compressor is the Truck Air. (by test - Harry Lewellyn (http.www.eco4wd.com/) tested a bunch of compressors). With four tires, it will still be slow.

David K - 1-16-2006 at 09:20 PM

Jim, I have a portable (built in battery) air pump... can run off cig lighter if battery gets low... It is slow, as most cig lighter pumps are... I get 2 psi per minute fill rate in my BFG 16" tires. So starting from 15psi, it takes 7 1/2 minutes to get to 30psi. Those 30 minutes are spent making out with Baja Angel!

(well, maybe we have a beer or lunch as well).

The portable air pump is from Campbell Hausfeld...

Viagra in a silver bottle

Ken Cooke - 1-16-2006 at 09:32 PM

Quote:

Originally posted by surfer jim
Ken C and Roberto bring up a good point...how to air UP... I didn't want to go down as no way to air up when done.....

Ken....how much does tank cost?...and how much does it air up (how many tires )

C02 is the fastest way to air up a tire - ~30 seconds per tire to go from 15 p.s.i. to 30 p.s.i. With C02, it is faster to air up than it is to air down.

With an el China cheapo Costco/PepBoys air compressor, you'll be stuck waiting for hours to air your tires up, listening to the loud clatter of the air compressor, and annoying your significant other looking like someone who doesn't know what he's doing. With a C02, your tires will pump up with authority, like Viagra your tires will quickly assume a manly stature in mere seconds. A good C02 setup will cost you ~$400...

David K - 1-16-2006 at 09:47 PM

OH jeeze Ken...

My sweety likes it slow...

Like I said I give her a full 30 minutes to enjoy...

(that's 7 1/2 minutes for each tire)...

No quickies! :lol:

Roberto - 1-16-2006 at 10:42 PM

Quote:

Originally posted by surfer jim
Roberto...does that run off of 120 ac or 12v dc?

120V - that's why I need the inverter. But MANY TIME faster 12V compressors. A couple of minutes per tire and I'm done, and I inflate back up to street pressure if I want to (50psi).

A CO2 tank will do a faster job, but it's much more expensive and needs to be refilled. Plus, I use the inverter for all kinds of things (computers, coffee machine, small power tools ....).

[Edited on 1-17-2006 by Roberto]

Sharksbaja - 1-17-2006 at 01:20 AM

Quote:

Originally posted by Mexray

Of course those were the days down at Pismo Beach before the State took over the beach and cut back on the fun! In those days, you could run down there on a three-day holiday and camp back in the dunes with 100's of your new best friends - and the noise and dune running would pretty much go on around the clock! Crazy days, but most everyone survived without 'Big Brother' and the State of Calif Park Ranger N-zi's looking over our shoulders! Goodbye Pizmo, Hello Baja California!

Ah, the good ol days. Years ago I would make the run from Pahrump Nev. to Pismo in an old VW bus. Upon arrival I would air down the tires and drive all over the dunes delivering firsworks to the awaiting throngs. Lots of fun until the State went Gestapo at all the beaches.

bajataco - 1-17-2006 at 08:44 AM

Quote:

Originally posted by Bruce R Leech
why is Co2 better than compressed air? I can get my dive tanks filled allot cheaper than buying Co2.

Compressed air doesn't really compress much. Liquid CO2 is highly "compressible" because it is actually stored in the tank as liquid, which wants to evaporate into a gas. This evaporation process builds enormous pressure inside the vessel, and a great deal of air supply when released through the hose into your tires. As the liquid level in the tank drops, it just allows more room for the CO2 to evaporate, keeping it under pressure. With a SCUBA tank, you will only get about as much volume of air as the size of the tank. So you will quickly exhaust your stored air with just one attempt at refilling your tires. The CO2 on the other hand, is good for many repeated fill-ups, and it is FAST!!

There is no doubt that CO2 is the fastest way to air up your tires. However, like an on-board 12V air compressor, it has its advantages and disadvantages. The trade-off (especially for someone doing extended trips in Baja) is that you can get an endless supply of "free" air from a compressor. Better yet, at a relatively low payload cost. CO2 will cost you money every time you need to get the tank filled (including time and fuel to take it to the retailer/shop to get it filled) and it has a limited supply, so once you run out, you are out. For a shorter trip to Baja this likely isn't an issue. A 10lb. CO2 tank will probably fill about twenty 33" tires from 20-40 psi. That would allow a single vehicle on 33"s to air up 5 times. For the 10lb tank I cited in this example, 10 pounds is not the overall weight, it is 10lbs. of liquid CO2 - it actually weighs about 27lbs. full. That is the little tank. The one more commonly seen is the 20lb bottle, so you could double that. If you are already loaded with bunches of weight due to all of your 4wd accessories, camper, and/or camping gear, supplies, and toys, you may already be at or over your vehciles GVWR (gross vehicle weight rating). In this case, waiting the extra time it takes to use a 12V compressor might be a wise choice. But for the ULTIMATE in speed and convenience, the CO2 is where it's at. The ideal would be to have the option to use either one at your disposal. If you are doing a light trip, take the CO2. If you are doing a heavy/extended boondocking trip, use the 12V.

I did an article on my own (12v compressor) on-board air setup at my website.

David K - 1-17-2006 at 09:10 AM

Man you make a great web page! Good job Chris!!

bajataco - 1-17-2006 at 09:50 AM

Quote:

Originally posted by David K
Man you make a great web page! Good job Chris!!

Thanks David

By the way, I think I could have worded my post above a little bit better. Using a scuba tank, the air is indeed compressed (to what? 2,000-3,000 psi?) but I guess what I am getting at is the volume you get from air vs. CO2. Because of the CO2 being in a liquid form that becomes a gas, you get much more volume of "air" from a tank of CO2 vs. a tank of regular air. Even though the SCUBA tank may be under enormous pressure, you don't get nearly as much tire-filling power from it, and would soon run out.

Sharksbaja - 1-17-2006 at 03:35 PM

Awesome stuff Ray! Gracias