Improving traction in mud with a WDH

oldbloke · Guru

Improving traction in mud with a WDH

86GTS · Guru

Who wants to take a caravan into a situation that requires the engagement of 4x4?
Too many travellers these days overating the capabilities of their rigs & themselves.

KJB · Guru

If Rear Wheel Drive ----- less traction ( not what is needed)...............KB

yobarr · Guru

KJB wrote:
If Rear Wheel Drive ----- less traction ( not what is needed)...............KB

As usual, Kerry, you are correct. If the driver of the vehicle being discussed were to go to extremes, they could actually tension the WDH so much that the rear wheels of the car would leave the ground. This would help to force the caravan's wheels, and the front wheels of the car, further into the mire, totally immobilising the car if it were rear wheel drive only. However, if the WDH were used in the same way that most seem to be used, the effect would be minimal, as many seem to mistakenly believe that the main reason for using a WDH is to make the car and van more level, but that is not at all important unless the van has non-load sharing suspension. Cheers

-- Edited by yobarr on Wednesday 27th of April 2022 09:35:53 AM

Dougwe · Chief one feather

I have a spare padlock waiting in the wings

rgren2 · Guru

Letting a bit of air out of all the tires would be more beneficial.

bratboy · Veteran Member

Dougwe , I think you may need that lock . I suspect op may be utilising his rather large wooden spoon .

Aus-Kiwi · Guru

Tyre with tread , less torque on WDH , LSD , lower tyre pressures . A little momentum on the slippery, muddy areas ? Eas off throttle to prevent wheel spin.,

deverall11 · Guru

rgren2 wrote:
Letting a bit of air out of all the tires would be more beneficial.

Mud is not like sand.

Peter_n_Margaret · Guru

Letting LOTS of air out is almost always the best action.
07-06 2.JPG 07-09 3.JPG 13-08 2 Ireland.jpg 1995 Currawinya NP 2.jpg 1995-10 Strz 5E.jpg
Cheers,
Peter

Izabarack · Guru

oldbloke wrote:
..if the loads is spread out (distributed) over all of the axles more evenly because you are using a WDH. Wouldn't it be less likely that your axles would sink into the mud?

I dont have a WDH so have never before wondered about the effect in muddy conditions.

Using or winding the tension up, on a WDH, would cause the front axle to sink deeper into the mud and create additional resistance to be overcome by the driving axle which now struggles more with reduced traction. Thats in the case of a rear wheel drive vehicle. Front wheel drive might just get a tiny bit more traction on the drive axle wheels. Might just be smarter to drop tyre pressures, a lot, and engage 4WD before entering the muddy conditions. Once the drive wheels start spinning, you are likely looking at a recovery situation that fiddling with WDH settings will not affect.

There are muddy conditions and there are muddy conditions. Black soil plus a couple of mm of rain and you will go nowhere. I recall an incident at the river camp at Longreach when a few numpties ignored the signs and parked off the designated parking area before a couple of light showers. They had to be dragged out by a Council supplied road grader.

Stewart · Senior Member

I had a thought. What if the wdh was reversed. So chains hooked on to the tow shank and fixed to the caravan draw bar would the results be the same for towing. (nothing to do with mud). Cheers Stewart

Hitting the road · Senior Member

Hmmm, I'd be thinking the total opposite...best remove the WDH bars. With a conventional 2wd the trailer ball weight would be back on the drive where it is needed. If there was a slight tendency to lift a bit of weight off the steer...all good in fact as less plough effect.

Sometimes high tyre pressures would assist as the tyres will sink in to the mud finding bite, where low pressures will see the tyres "floating" over the mud...

Might get a bit of understeer with the lighter front end but nothing some careful driving wouldn't control. Different with a 4wd, a WDH would make little difference I reckon as all wheels would be driving anyway...

Remember the old VW beach buggies...they'd go almost anywhere with just rear wheel drive as the weight was over the drive, and the front end was quite light therefore didn't bog in as much...

yobarr · Guru

Hitting the road wrote:
Hmmm, I'd be thinking the total opposite...best remove the WDH bars. With a conventional 2wd the trailer ball weight would be back on the drive where it is needed. If there was a slight tendency to lift a bit of weight off the steer...all good in fact as less plough effect.

Sometimes high tyre pressures would assist as the tyres will sink in to the mud finding bite, where low pressures will see the tyres "floating" over the mud...

Might get a bit of understeer with the lighter front end but nothing some careful driving wouldn't control. Different with a 4wd, a WDH would make little difference I reckon as all wheels would be driving anyway...

Remember the old VW beach buggies...they'd go almost anywhere with just rear wheel drive as the weight was over the drive, and the front end was quite light therefore didn't bog in as much...

Great post Dean, with perhaps your anology with the VW beach buggies being most relevant. Many of the points you make display your good understanding of simple physics, combined with healthy doses of common sense. Cheers

yobarr · Guru

Stewart wrote:
I had a thought. What if the wdh was reversed. So chains hooked on to the tow shank and fixed to the caravan draw bar would the results be the same for towing. (nothing to do with mud). Cheers Stewart

Interesting question that you ask here Stewart, but because I am currently dosed up on very strong painkillers after a bit of an incident yesterday, on the Roadtrain, I am unable to concentrate enough to offer a meaningful opinion. Perhaps others will be able to help, but my initial thoughts are that the weight being transferred would differ because of different leverage points? Just a guess though! Cheers

Peter_n_Margaret · Guru

The beach buggy is effective because it is a VERY light vehicle on large flotation area tyres.
It is unlikely that most can match that with a normal vehicle, even after letting the tyres down.
Cheers,
Peter

Stewart · Senior Member

Guess who. Haha. https://youtu.be/aK1Ozo9f_KQ

Stewart · Senior Member

Thanks Yobarr. Sorry your not well. Hope you improve soon. Would love to hear you thoughts. Cheers Stewart

oldbloke · Guru

I think some are not understanding the very basic concept. If your in camp and it rains and you need to get out. Nothing to do with being intentional, as i think someone suggested. I think its just an over looked advantage of having a WDH. We are talking a 4x4 here too. So more weight on the front wheels will aid traction. I'm not looking for suggestions on how to get out of a bog.

No idea how where adjusting to extremes come from. That's very weird.

The basic principle is that the more weight is on 2 wheels they are more likely those two wheels will bog down. (it's called point loading, this is when all the load is on just one or two polnt instead over a large area) The more the load is spread across as many tyres as possible less likely for the wheels to sink on the mud.

Very simple really. Pretty basic stuff. Just common sense really.

So, although there are other options, I'm just suggesting that a WDH may sometimes prevent you getting bogged.

However without a WDH you are more likely to get bogged due to point loading on one axle all things being equal.

oldbloke · Guru

The load is spread the less it will sink. Simples.

And that's what WDHs do, spread the load across the wheels.

dogbox · Guru

yobarr wrote:

Hitting the road wrote:
Hmmm, I'd be thinking the total opposite...best remove the WDH bars. With a conventional 2wd the trailer ball weight would be back on the drive where it is needed. If there was a slight tendency to lift a bit of weight off the steer...all good in fact as less plough effect.

Sometimes high tyre pressures would assist as the tyres will sink in to the mud finding bite, where low pressures will see the tyres "floating" over the mud...

Might get a bit of understeer with the lighter front end but nothing some careful driving wouldn't control. Different with a 4wd, a WDH would make little difference I reckon as all wheels would be driving anyway...

Remember the old VW beach buggies...they'd go almost anywhere with just rear wheel drive as the weight was over the drive, and the front end was quite light therefore didn't bog in as much...
Great post Dean, with perhaps your anology with the VW beach buggies being most relevant. Many of the points you make display your good understanding of simple physics, combined with healthy doses of common sense. Cheers

might want to check how many wheels will actually be driving unless diff locks are fitted ?

KJB · Guru

"Bogging" to the axles and even deeper or sometimes less deep - (no hard bottom to the wet ground......) or "spinning" (no traction) on the slippery wet surface - big difference in the way you deal with each situation......... there is no one answer. KB

Are We Lost · Guru

I think it depends on the mud. If there is a chance of getting on top of it like sand, then deflating tyres and tensioning the WDH could help.

But I vividly remember the opposite situation one time. I had a Falcon with slightly wider wheels than standard ... maybe an inch. On an outback trip with 2 mates we got caught in a drenching rainstorm, and the road quickly turned to mud. We got bogged multiple times but were able to get moving again with the 2 mates sitting on the boot. Rinse and repeat. In the meantime, the locals would drive past us in their vehicles with slightly narrower tyres. The narrower tyres meant extra weight per square inch enabled them to get a little deeper in the mud and find traction.

Maybe if it had rained for a day instead of a few hours it would be a different story as the mud would be deeper.

rgren2 · Guru

deverall11 wrote:
rgren2 wrote:
Letting a bit of air out of all the tires would be more beneficial.
Mud is not like sand.

Neither is rocks or gravel, deflating your tires in muddy conditions gives more traction.

Hitting the road · Senior Member

Thanks fro the comment yobarr...get well soon eh, really sorry to read you were injured while at work...we all know working around trucks can be hazardous at the best of times...especially when mucking around with multiple trailers!

Hitting the road · Senior Member

But I vividly remember the opposite situation one time. I had a Falcon with slightly wider wheels than standard ... maybe an inch. On an outback trip with 2 mates we got caught in a drenching rainstorm, and the road quickly turned to mud. We got bogged multiple times but were able to get moving again with the 2 mates sitting on the boot. Rinse and repeat. In the meantime, the locals would drive past us in their vehicles with slightly narrower tyres. The narrower tyres meant extra weight per square inch enabled them to get a little deeper in the mud and find traction

Exactly...thinner or higher tyre pressures will see you possibly cut through the surface mud or even sand to the firmer ground underneath. Low tyre pressues won't help at all. Why do Toyota still fit pizza cutter tyres to some of their 4wd's? Why do mining companies leave the stock standard thin tyres on their 4wd's? For the reasons above...

Yes, fat tyres will assist in sand...with momentum..but not in mud. Hence the "mud" tyres with large lugs to cut through the mud and to fling any mud caught between the lugs off as they spin. They do not "float" over the surface.

Peter, if you had mentioned in your initial post that you were referring to a 4wd using a WDH system, that is a totally different argument...as i wrote, imo with a 4wd not an awful lot of difference as all wheels would be driving...

Peter_n_Margaret · Guru

Hitting the road wrote:
..thinner or higher tyre pressures will see you possibly cut through the surface mud or even sand to the firmer ground underneath.

That vehicle is not "bogged". It just has insufficient traction. Different problem. Like ice on the road.

Cheers,

Peter

yobarr · Guru

dogbox wrote:
yobarr wrote:

Hitting the road wrote:

Hmmm, I'd be thinking the total opposite...best remove the WDH bars. With a conventional 2wd the trailer ball weight would be back on the drive where it is needed. If there was a slight tendency to lift a bit of weight off the steer...all good in fact as less plough effect.

Sometimes high tyre pressures would assist as the tyres will sink in to the mud finding bite, where low pressures will see the tyres "floating" over the mud...

Might get a bit of understeer with the lighter front end but nothing some careful driving wouldn't control. Different with a 4wd, a WDH would make little difference I reckon as all wheels would be driving anyway...

Remember the old VW beach buggies...they'd go almost anywhere with just rear wheel drive as the weight was over the drive, and the front end was quite light therefore didn't bog in as much...

Great post Dean, with perhaps your anology with the VW beach buggies being most relevant. Many of the points you make display your good understanding of simple physics, combined with healthy doses of common sense. Cheers
might want to check how many wheels will actually be driving unless diff locks are fitted?

Good point Dean, perhaps understood by few. Unless a "4WD" vehicle is fitted with diff locks, it will only actually be 2wd, driving only one wheel on each axle at any one time. Similarly, a 2wd vehicle will be only 1wd, driving one wheel on the drive axle. Some year ago I worked in cotton-country around Gurley, NSW, and when I arrived in my F100 351V8 with its limited slip diff all the local cowboys, driving their Patrols and Cruisers, laughed at me, asking me where I thought I was going in my F100. However, after lots of rain, my car was the only vehicle able to deliver us to the local pub, with the Patrols and Cruisers dropping both wheels on one side into one of the many ruts, leaving the other two wheels on the high,unweighted, side spinning hopelessly. Much fun was had rescuing these cars! Few understand how a 4wd works, evidenced some years ago when I was visiting my father who lived on the beach front in NSW. We were enjoying an ale when there was a knock on the door, a couple of chaps asking for help as they were stuck on the beach. These chaps had each recently bought a 4wd and had decided to try them on the beach. As soon as we saw the cars, we knew what was wrong .. they hadn't engaged the front hubs, and the cars were sitting down at the rear. "Derr, we put it in 4wd" they both said, showing us the range selection gear lever. Cheers

-- Edited by yobarr on Thursday 28th of April 2022 10:48:47 AM

Bobdown · Guru

might want to check how many wheels will actually be driving unless diff locks are fitted?
Good point Dean, perhaps understood by few. Unless a "4WD" vehicle is fitted with diff locks, it will only actually be 2wd, driving only one wheel on each axle at any one time. Similarly, a 2wd vehicle will be only 1wd, driving one wheel on the drive axle. Some year ago I worked in cotton-country around Gurley, NSW, and when I arrived in my F100 351V8 with its limited slip diff all the local cowboys, driving their Patrols and Cruisers, laughed at me, asking me where I thought I was going in my F100. However, after lots of rain, my car was the only vehicle able to deliver us to the local pub, with the Patrols and Cruisers dropping both wheels on one side into one of the many ruts, leaving the other two wheels on the high,unweighted, side spinning hopelessly. Much fun was had rescuing these cars! Few understand how a 4wd works, evidenced some years ago when I was visiting my father who lived on the beach front in NSW. We were enjoying an ale when there was a knock on the door, a couple of chaps asking for help as they were stuck on the beach. These chaps had each recently bought a 4wd and had decided to try them on the beach. As soon as we saw the cars, we knew what was wrong .. they hadn't engaged the front hubs, and the cars were sitting down at the rear. "Derr, we put it in 4wd" they both said, showing us the range selection gear lever. Cheers

-- Edited by yobarr on Thursday 28th of April 2022 10:48:47 AM

Yobarr, that story doesn't ring true........every Cruiser I've had has constant AWD and Diff Locks.

Cheers Bob

oldbloke · Guru

The more the load is spread the less it will sink. Simples.

And that's what WDHs do, spread the load more evenly across additional axles. This is why we let the tyre pressure down in mud, to spread the load over a greater area. :) It's the same principle. DOH

Well I'm amazed. All these xspurts here and nobody understand that bit of basic physics. "point loading".

You would not drive a star peg in sideways would you?

Cheers :)