What's your dune climbing technique?

[the evil twin]

Diff locks can make the world of difference as it stops the front ploughing in.
Thats why one of the old school techniques is to reverse up the dune if you have LSD or rear locker and not front.

Tyre pressure will always be the best aid tho and it is an exponential thing.
Dropping, say, 3 PSI from 18 to 15 makes a bigger difference in footprint than dropping 6 PSI from 24 to 18

For disbelievers on 4WD courses I use a marker to show the difference in footprint between 24/18/15 and it is a bit of an eye opener.

Lower pressure on sand means less load on the engine, less fuel used and much less stress on the Driver.
You want to 'float' not 'plow'

For dunes I use Gods gear (2nd low in a manual) or 1st high and on occasion 3rd low if the approach and incline permit.
If you don't make it let the vehicle stall out
DO NOT punch the Clutch in a manual as the drive backlash from windup torque is enormous.
Do a stall recovery procedure, if you don't you significantly increase the odds of a Utube Moment.
When safely back at the bottom assess if a tad bit more momentum will get you over and Mach 3 is def not an option.
If a judicious bit of extra right boot for an extra couple of K's at the bottom won't help, start dropping tyre pressure.

[TimE]

Big Red, 19 psi all round, 2nd low (pre 43% gear reduction and pre elockers), run up at 3,600 rpm, easy

[Bulbous]

Yokohama A/T-S 285/75 R16 LT

Deflate to 12 PSI in Front tires, 10 PSI in rear tires. Have fun.
liwa-oasis.jpg

[paulyg]

When we did a west to east crossing of the Simpson Desert, it was quite dry, I started with 18psi, but it was hard going, dropped pressure down to 15psi front and 16psi rear and had no more problems. Sometimes it can be hard to tell what conditions are going to be like until you start driving, then adjust as needed.
Big Red I had 12psi front and 14psi rear.

[MB]

Great question Cuppa and jealous as you're both out there amongst our great big land mate! Being a Mexican mountain man myself with a heavy ute too intrigues me this thread. Our weights in sand versus arse end safe/trouble free PSi must have some consideration I imagine. As ET kindly mentioned of student deflation footprint displays at varying PSi's I'm thinking heavy rigs versus tall tyres and safe rim sizes could matter too? Would be cool to have a rough guided percentage of footprint over tyre versus varying load PSi I guess, even sounds difficult typing that wacky theory, lol :-)

[Avo]

psi guide for sand,dunno about the uphill bit but this is what i learnt..

you should be able to back off go pedal(cant spell excalorator) and come to a rolling stop....gentle as easy does it...down here when i see sand it's straight to 10psi and to be honest even other places i go for 12...the hard bit about hill climbs is there is usually a lip at the bottom or the top so speed sometimes doesn't or isn't always an option..down here unless its callcup we just gently and easy..as long as ya have revs on hand you usually have aenough tourque to deal with most of the sand and hills here

[Cuppa]

Great question Cuppa and jealous as you're both out there amongst our great big land mate! Being a Mexican mountain man myself with a heavy ute too intrigues me this thread. Our weights in sand versus arse end safe/trouble free PSi must have some consideration I imagine. As ET kindly mentioned of student deflation footprint displays at varying PSi's I'm thinking heavy rigs versus tall tyres and safe rim sizes could matter too? Would be cool to have a rough guided percentage of footprint over tyre versus varying load PSi I guess, even sounds difficult typing that wacky theory, lol :-)

The weight of a laden ute does affect the footprint, & recommended pressures are, I suspect mainly for wagons & possibly less weight. Even for road/dirt road driving I am yet to pick perfect pressures. Since leaving home I have gradually reduced pressures from what I started out with. I know the 'rule of thumb' for pressures in LT tyres is a 6 psi increase from cold to hot, but have been unable to achieve this in the temperatures we've been driving in. Mainly I get a pressure increase of around 10 psi regardless of the cold pressure, we have been driving slow though. Rarely above 80kph & often less on bitumen, & 40 to 60 on dirt. 40 psi rear & 30psi front seems ok on dirt. (cold) 4 or 5 psi higher for long sretches of bitumen. Bridgestone D697's 16" 265's.

Have to be a bit careful not to create too much sidewall bulge on the sharp quartz gravel used in these parts, already have one cut sidewall - not punctured & still holding. Was lucky. Copper in Boulia reckoned not to deflate at all.

For dunes the concensus of 18 psi or less all round - I would tend to translate as 18 front & maybe 22 to 24 rear (as per Old Wal's post) for our touring ute depending upon how full our tanks
are. But 'reading the sand' & adjusting to achieve a 'rolling stop' seems like excellent advice. I certainly failed to achieve a rolling stop & as ET suggested it felt hard on the transmission. I'll try the front diff lock another time too.

Off to Innaminka & then the Coongie Lakes - I gather there are dunes to cross there, albeit not 'Simpson sized" so will get a chance to experiment further.

[GQtdauto]

The weight of a laden ute does affect the footprint, & recommended pressures are, I suspect mainly for wagons & possibly less weight. Even for road/dirt road driving I am yet to pick perfect pressures. Since leaving home I have gradually reduced pressures from what I started out with. I know the 'rule of thumb' for pressures in LT tyres is a 6 psi increase from cold to hot, but have been unable to achieve this in the temperatures we've been driving in. Mainly I get a pressure increase of around 10 psi regardless of the cold pressure, we have been driving slow though. Rarely above 80kph & often less on bitumen, & 40 to 60 on dirt. 40 psi rear & 30psi front seems ok on dirt. (cold) 4 or 5 psi higher for long sretches of bitumen. Bridgestone D697's 16" 265's.

Have to be a bit careful not to create too much sidewall bulge on the sharp quartz gravel used in these parts, already have one cut sidewall - not punctured & still holding. Was lucky. Copper in Boulia reckoned not to deflate at all.

For dunes the concensus of 18 psi or less all round - I would tend to translate as 18 front & maybe 22 to 24 rear (as per Old Wal's post) for our touring ute depending upon how full our tanks
are. But 'reading the sand' & adjusting to achieve a 'rolling stop' seems like excellent advice. I certainly failed to achieve a rolling stop & as ET suggested it felt hard on the transmission. I'll try the front diff lock another time too.

Off to Innaminka & then the Coongie Lakes - I gather there are dunes to cross there, albeit not 'Simpson sized" so will get a chance to experiment further.

There is sand between you and Innamincka via walkers crossing but not much in dunes , funny what you say about tyre pressures of road and what the cop said , I was loaded up that much that I scraped the rear tyres on the guard if a hit a moderate bump but if on dirt would air down to about 22psi .
This would increase to about 26 as the tyre heated up , no sidewall damage at all and did some rocky tracks , only puncture I got was from crap on the ground at the Arkaroola camp site .
Opinions vary with tyre pressures on dirt and rocky tracks but I've found 22-26 to suit mine and gives me a softer ride .

[happygu]

Cuppa,

Airing down is definitely the key. 18 PSI is my rule of thumb for sand and I used this all the way across the Simpson, and we were fully loaded with food, water for 4 and fuel to get from Birdsville to Alice. With our weight, we would have been well over the load capacity, and heavier than your ute

I drove the hardest line up Big Red in my 3 Litre, but dropped to 12 PSI on my first run just to be sure I would do it first go and we sailed up it whereas everyone else couldn't make it even with massive runs at it ...

I did notice however, that the NA 4.2 Patrol in our group and another we came across struggled the most out of all the vehicles, and ran out of puff way earlier than the Turbo'ed vehicles ... not sure if it was just lack of confidence, lack of driver skill, not letting the tyres down enough, or just the short power curve, but don't feel too bad about struggling a little

Mic

[Mc4by]

I haven't done too many huge dunes but around here I have done Whitehills a few times. 18 psi and second low (auto) worked pretty good. I tried with the front lockers after I had them installed and it made a big difference.