Thread: Driving on the beach

Originally Posted by JamesH

Went fishing* the other day and it involved a 10km trek up a beach.

For me it was a no brainer, down go the tyres to 18psi, in goes the CDL and get up to a gentle cruising speed of low range 3rd or thereabouts.

Well I made it safe and sound but there was some moisture in the sand and it was not a hard job requiring great skill and a tractor. One of us also motored along happily in a fully loaded Subi Outback.

One of our group reckoned not locking the CDL was the way to go and he rolled along in high range 2nd at 18psi (Defender).

We both made it without any trouble so horses for courses and I don't want to open a can of worms and another CDL debate but getting bogged or not getting bogged aside what option would minimise stress on the vehicle drivetrain and engine? The reason i ask is my radiator is in need of attention and it was getting hot plodding up the beach someone suggested leaving the CDL out would have been easier on the temp.

Thoughts?

The CDL on a soft surface such as sand will not add significantly to the load on the engine or stress on the drivetrain (any buildup of torque will be immediately relieved by slippage on one or more wheels), and will help only when one wheel starts to spin - which driven appropriately, with the correct tyre pressure, on level sand, should be never.

So my feeling is that it will make no significant difference. On a sandhill I would engage it, but I doubt even then if the difference would be all that great unless the sand is rough (which it often is on churned up sandhills where others have tried to get over).

John

Having the CDL maximises traction whether you needed it or not - if you suddenly hit a very soft patch it may have made a difference.

Likewise if your car had been a part time 4wd you may have also made the trip happily in 2wd if your tyres had let down - VW beach buggies are 2wd and I used to drive quite happily on the beach in my Suzuki Sierra with 2wd and only used 4wd to get on and off the beach. My Subaru was also very good on sand in 2wd.

As said - CDL maximised traction - even if you do not need it in the specific bit of terrain.

Garry

Driving offroad without the CDL engaged will rapidly destroy your centre diff/T-case. Simple as that. Plenty of people have found out the hard way.

Hard-packed beach sand probably won't do too much damage though.

I doubt the cdl will affect engine temperature.

I always have the CDL engaged in my 110 on sand, (or any loose surface). If I don't the Traction Control activates all the time, when CDL is engaged it hardly acitvates. Also as said before if you don't have it engaged you can find your self getting bogged very quickly if you suddenly hit some soft sand, and you can't forget to put it in, (if it is already engaged), if you have to cross a creek.

Cheers,

Tim

The rule for a CDL is simple.

If it won't cause windup, lock it up.

Any form of sand is sufficiently slippery to have no chance of windup. Therefore, lock it in.

A previous poster said that if you are driving at the correct pressures there is no chance of wheelspin. This is correct only if all four wheels have exactly the same resistance -- ie, they are on ground of equal nature, and have the same weight on them, as may be the case in a vehicle with a 25/25/25/25 weight distribution travelling on the flat at a constant speed.

If this varies, for example ascending a slope, then clearly the rear wheels have more weight on them than the front, and thus more traction. The centre diff will attempt to drive the shaft easiest to turn, which is the front. The same will be true when turning, or in any other situation where the front axle has different traction to the rear, which is almost by definiton any offroad driving worthy of the name.

If the CDL is not locked "drive" will go the axle easiest to turn, which will certainly impede motion. Hence, lock the CDL to ensure a 50/50 "drive" distribution front and rear.

Not using the CDL may see you through, but the car is working harder than it needs to. This will be most apparent on traction control models as the traction control system attemps to equalise torque across four wheels, instead of two sets of two wheels on an axle.

If you drive say a traction-control equipped Defender up a corrguated incline you will see the traction control activate. This is for same reasons outlined above -- the rear has more weight than the front, thus the CDL unlocked attempts to drive the front axle more as it's easier to turn. If the CDL is engaged then you'll see the traction control less active.

Not locking the CDL on sand makes as much sense as trying to drive it at road pressures, or drive rocks in high range.

Well i will go against the trend here, i dont think CDL is always necessary unless your going through some very soft boggy patches or the beach is very soft and dry, i actualy think it slows you down and makes you cut in more when your out on the dunes traveling quick and turning.

I dont bother locking CDL at all in my county on the beach unless its really cut up and soft, recoverying someone or playing in the big steep soft dunes up north, but i also run 37s at 5-6psi. If you want to make it easier i would start with droping your pressures, 18 sounds pretty high, most tyres will happily run at 10-12, most of the time when im taking people out on the beach for the first time i tell them to go to 14 and we see how it goes from there, its amazing how much difference those last few PSI make some tyres dont sit well until around 12psi or lower.

I will also go against the trend here,but mine is a D2,therefore has TC.I wont use the diff lock on hard sand as you can easily get wind up.

In a non TC vehicle such as yours,this can also happen,but you also need to be able to get it in quickly if needed.

In soft sand i always have the diff lock in.

And 18 psi is what i run on the beach,but make sure you keep your speed down or you will cook the tyres.

I also tend to stay in high range unless the going is tough,going a bit faster in high range may have increased the airflow through the radiater,and kept engine temps down.

I don't use the CDL in my D2 on the beach.

I do use the one on the county.