What's the proper way to drive in deep sand

[SandMan]

Air down below 15 psi. - the lower the better.

Wider tires don't help - they'll just push a larger pile of sand in front of your tire. Most of the classic sand tires (Michelin XS, Pirelli Scorpion Dakar etc.) are 7.50R16 - narrower than any current stock Land Rover tire. They work in the Sahara desert - they'll work for you.

Taller tires aired down will keep your axles out of the sand and minimize your rolling resistance. You want to lengthen your foot-print, not widen it. A mild tread helps.

Not just MHO

SC

I agree with everything in this thread but ... the above quote. It actually contradicts itself.

What reducing the air pressure in the tires does IS make your tire wider. How can you say air down the tires and then say wider tires don't help? I can't help but ask that question. That dog just don't hunt!

The sand tires you quote are used on rally cars weighing less than half that of a Disco and traveling 3 times the speed. Ever see what happens to one of those babies if they slow down in the sand? They sink! Right down to the frame.

Agree taller tires keep the axel out of the sand, but how do taller tires minimize rolling resistance? Or do you mean narrower tires reduce rolling resistance. The whole pushing sand with wider tires only means your speed is too slow. Maintain the speed/momentum to stay ON TOP of the sand.

The keys to driving on the sand, and these worked for me driving the Disco from Dubai-UAE to Jeddah-KSA, to Amman-Jordon and back to Dubai (get out your maps if necessary):

Air the tires down to safely above bead loss
Lock the diff and leave it there
Starts and stops are made slowly in middle/low gears
KNOW where you are going ... look ahead at least 1/4 mile
Maintain your speed and the momentum or start digging
Use Low range only when "getting out"
Bring the proper recovery equipment

Tires: the best are those with tread patterns that cross the tire left to right, not front to back (I know these are much louder...on the street). My favorites are Mickey Thompsons for their tread pattern which continues to the side wall (which is great when aired down).

Of course, you as the driver make the final call for your rig. These are just my opinions and really don't mean anything (unless RoverChic finds them impressive and will go out with me ).


SandMan

 

[jymmiejamz]

in the outer banks area i have never needed to air down the tires on my disco. i am running 265/75 A/Ts and i dont have any trouble. as far as braking goes, i only use the brake to slow down if i have to. never come to a fast stop (unless in an emergency) because you will just push a mound of sand infront of your tires, making it hard to drive away. also, use very light acceleration until you are already moving along because your tires will just spin. and if you are in the corolla area and you come to large puddles, check the depth. the locals dig treches in the middle of the puddles. i got caught in one of those death traps and it sucked.

 

[bell03disco2]

The only place I have ever done any sand driving was the OBs, but I did not need to air down. I live in NW Florida (Near Panama City) and we have section of beach, maybe a 1/4 mile that civilian vehicles can traverse, but I have been leary of driving on this sand because it is all the soft sugar type. That is why I have CDL waiting for install so that I can cruise the beach.

 

[Ho]

What reducing the air pressure in the tires does IS make your tire wider. How can you say air down the tires and then say wider tires don't help? I can't help but ask that question. That dog just don't hunt!

ok, so the contact patch becomes wider...

how come nobody mentioned lenghtening of the contact patch?

 

[SandMan]

ok, so the contact patch becomes wider...

how come nobody mentioned lenghtening of the contact patch?

You mean like half tracks?
Now that's lengthening the contact patch!

 

[Ho]

You mean like half tracks?
Now that's lengthening the contact patch!

exactly, that's how you increase the patch. not the width.

 

[SandMan]

Ho?

exactly, that's how you increase the patch. not the width.

What is your experience when letting down the tires? For me, the width increase is about 5 times that of the length increase. Unless you completely flatten the tire. Then, it is about an even 50/50. This analogy is using 270/65/16 non-radial tires. Other sizes and makes will vary.

So, for every 1/5 of an inch increase in length, the 1 inch increase is width is negligible because I lengthened the patch?

Sorry to be a stickler, but I need some help with the physics. I don't want to continue sending out misinformation.


SandMan

 

[LittleCountry]

Definately decrease the air pressure in your tires.... your rig will ride higher on top of the sand instead of digging down into it. This also helps to reduce the amount of strain on the engine since you're rolling on top of the sand and not plowing through it.

In 'sugar' sand drive at a slow, even pace. Accelerating too quickly will cause loss of traction and bury you.

Try to stay in the ruts made by other vehicles unless they are too deep.

Stay on the hard pack and out of the "sugar sand". On the Washington coast it is pretty compact where it is legal to drive on the beach (Long Beach)

Stay out of the clam beds (the softer sand close to the water line). This preserves the clams and other stuff. Stay away from high grass too.... birds nest there generally.

Very important: Watch the tides! Don't get trapped on the wrong side of areas of the beach that are impassable at high tide. I took a ford mustang on the beach once and almost found myself in some real trouble (yikes, that was close) - I always have a tide schedule now.... -Oh, and park well above the high tide line (drrr!)

In the event that you do lose traction, don't spin your wheels to try to dig out of it. It only takes a couple of pumps on the gas to sink you down. The best solution is to decrease your tire pressure, shift to low range and back out of the rut you came in on before trying to proceed. -I just picked up a pretty inexpensive air

Always watch for pedestrians, animals, debris.... blah, blah, blah

Give the underside of your vehicle a good freshwater rinse when you come off the beach to remove corrosive sand and salt.

 

[Ho]

What is your experience when letting down the tires? For me, the width increase is about 5 times that of the length increase. Unless you completely flatten the tire. Then, it is about an even 50/50. This analogy is using 270/65/16 non-radial tires. Other sizes and makes will vary.

So, for every 1/5 of an inch increase in length, the 1 inch increase is width is negligible because I lengthened the patch?

Sorry to be a stickler, but I need some help with the physics. I don't want to continue sending out misinformation.


SandMan

ed, how do you measure the "5 times increase" and are you able to see if the weight is evenly distributed to this new found wider patch? or is it mostly visual effect ... that the tire looks wider. perhaps radial tires behave differently from the non-radial?

here the tires are aired down below 15 psi. look at the visual width increase in the tire. wider for sure eh? but, look at the track mark. it's deep and shapped just to the width of the tread of the tire, not really the full width you see on the tire.

 

[draaronr]

Long beach WA is like concrete, you wouldn't make it ten feet into the sand here with anything other than a 4x4. Even then it can be a pain in the ass to go somewhere, in the am you can drive where the tide has receded and it is packed more firmly, although it is illegal here to drive there. As the day goes on you are forced to drive in the soft sand as the beach is lined with vehicles.

 

[scrover]

...For me, the width increase is about 5 times that of the length increase...

Physically impossible. Look at the angle of the sidewall to the sand (vertical)....now look at the angle of the tread to the sand (horizontal)....get it? Airing down the tire has very little effect on the width of the contact patch...and a very large effect on the length of the contact patch. The width appears to be increasing more than it is because of the bulging sidewall (as seen in Ho's picture). The length appears to be inceasing less than it is because you can't see it. The taller the tire - the more pronounced the effect. Starting out with a wider tire gives you, well, a wider tire, but that doesn't change what happens when you let the air out.

Here's my RRC LWB (heavier than any Disco) on Michelin 7.50R16s aired down to less than 1 bar - the contact patch is very narrow and very long - like, oh let's think, a tank track? (I didn't get stuck BTW) Hope that helps.

 

[SandMan]

Okay...so it's length not width?

Ho and scrover,

On my Mickey Thompsons I could physically measure the increase in width when I aired the tires down to 12 PSI. These were 33x12.5x15 that would go to 14 in width and this was easily measured in the sand due the sidewall treads on the tire. Remember, in the sand is where I can see this happen.

Ho, I must admit I can see in your photo the sidewalls are leaving a pattern in the sand as well. Not as pronounced as mine, but the "contact patch" is wider. On a hard surface the tire just looks wider, that is all...just looks. But put that bulging rubber in the sand and those sidewalls come into play and can really float the truck.

This is from my experience anyway. Any belted radial will deform out the sidewall at a greater ratio than across the length. I'm not sure about tires with reinforced sidewalls, etc.
I got 1.5 inches more in width in a depth of only 2 inches of sand, but it was pure guess regarding the 5 times. It may be much closer (2x?), but with a belted tire it definitely can't be the same or more (unless it is completely flat?).




In this photo, I think the widest tire was 8 inches. I'm not disputing the ability of narrow tires scrover. We drove the entire 3500 km and nobody got stuck. Sand is sand and if you are well prepared and know what you are doing, you'll never get stuck. I just wanted to get Ho's opinion (there goes his head) on contact patch.

Thanks guys,


SandMan