WDH

Stuss · Member

WDH

Greg 1 · Guru

They check everything. ATM, GVM, GCM, ball weight and axle loads.

Radar · Guru

Greg 1 wrote:
They check everything. ATM, GVM, GCM, ball weight and axle loads.

I personally don't believe that to be quite right.

The first thing they will look at is the tow vehicle tow rating then the trailer gross weight, if those 2 rating are in order then they may weigh the combination, then spit the combination and this all takes time and resourses.

Just saying if the gross combination weight is right for your vehicles then they may spit weigh the 2 vehiles then they may if you are seriously over on one end they then may tell you to adjust your weights before moving and remember this is after handing you a summons for being over weigh on one of the vehicles.

Now I have doubts if they can ask you to detach the trailer to weigh the ball weigh, lots of small reasons, my main reason would be they already have you for being overweight some where. They wil have grounded you for seriously being overweight.

With 43 years in road transport never have been asked to detach the trailer from the prime mover. That would not happen. The law enforcement officer would just ground the vehicle and tell you to adjust the weights,

Radar · Guru

Stuss wrote:
Hi I know this is a hot subject these days as theres more caravans on the road and more accidents, coincidently more police or heavy haulage checking us out for overload.
My mate reckons by using WDH will level the load as his GCM is good, but is well over on the GVM.
When the heavys weigh the van and the tug do they weigh them seperate or is it combined weight?
stuss

WDH will not adjust weighs, may make the combination look a bit level put a lot of strain on the tow ball, tow bar and the A frame they will not adjust weighs if either vehicle is over weight.

The law enforcing officer will weigh the combination, if that is suspect they then may spit weigh looking for a overload some where.

I doubt they will ever ask you to detach the trailer or allow you to on their weighbridge, my main reason is they already will have you for being overloaded some where and next instruction is to park your vehicle over there and adjust the weight after heading you a summons.

The trick is to load your vehicles and take them to a public weighbridge, if your over weight, adjust weights, check again and go down the road a happy camper.

Hope this of some help.

EJP · Senior Member

A WDH will lift the rear of the tow vehicle and transfer some of the weight from the rear to the front wheels. The overall GVM will not change. The increased weight on the front wheels will put extra strain on the front axles, bearings, steering, suspension and tyres. It may even increase the front axle rating over its limit. It will not change the GVM of the caravan.
Regards EJP

Stuss · Member

Thanks Guys for the replys Blew my mates theory out the window , he has dual cab Colorado with canopy boat and all acceseries that you need to take and hes way over.
Even my 2017 79 series single cab Ute with canopy and van Im over , so getting a GVM upgrade on Friday before we head north
Re Stuss

yobarr · Guru

EJP wrote:
A WDH will lift the rear of the tow vehicle and transfer some of the weight from the rear to the front wheels. The overall GVM will not change. The increased weight on the front wheels will put extra strain on the front axles, bearings, steering, suspension and tyres. It may even increase the front axle rating over its limit. It will not change the GVM of the caravan.
Regards EJP

Hi Ellis....Interesting observations you make,but they are,unfortunately,wrong. As you suggest,a WDH does indeed transfer SOME weight back to the front axle of the car,but I would suggest that there is no way that you will overload that axle unless the whole car was way over its GVM before you even fitted the WDH.Some of the weight taken off the cars rear axle is indeed transferred to the cars front axle,but a percentage of weight also is transferred to the vans axle group,thus increasing the vans GTM. (And obviously increasing the GVM).Many people seem to not realise that a WDH does NOT alter the ball weight (TBM). I have no doubt that your intentions were good,but information such as you have given only further confuses those members who have little,or no,understanding of how a WDH works. Many do not realise that adding a WDH,until it is tensioned,instantly increases the load on your rear axle because of the extra leverage created by the extra distance from the rear axle to the hitch point.With a WDH fitted,the weight on the rear axle increases by around 1.45 times the TBM. (145% of TBM).A McHitch makes a bad situation even worse by further increasing the distance from the rear axle to the hitch point.In my opinion,a WDH is not the cure-all that many idolising users seem to believe it to be.Better to buy a more suitable car,or a smaller van. Safe and happy travels to all. Cheers

-- Edited by yobarr on Sunday 3rd of June 2018 09:14:06 PM

-- Edited by yobarr on Sunday 3rd of June 2018 09:30:40 PM

-- Edited by yobarr on Sunday 3rd of June 2018 09:34:31 PM

Desert Dweller · Guru

WDH only disguise a problem, never used one in 80,000kms of safe travel.

They're an Aussie tradition, not commonly used overseas, particularly with euro type caravans.

-- Edited by Desert Dweller on Monday 4th of June 2018 06:30:39 PM

Pariss · Veteran Member

Hey Guys. Here is the definitive and correct answer to any WDH misconceptions some members have. Also, WDH ARE used extensively all over the world, particularly in the USA where Hayman Reece was invented. Cheers and enjoy the educational video. www.youtube.com/watch

Dickodownunder · Guru

Pariss wrote:
Hey Guys. Here is the definitive and correct answer to any WDH misconceptions some members have. Also, WDH ARE used extensively all over the world, particularly in the USA where Hayman Reece was invented. Cheers and enjoy the educational video. www.youtube.com/watch

Thank you Pariss.

That is a VERY informative video which should dispel a lot of myths re the weight transfer with WDH systems.

-- Edited by Dickodownunder on Monday 4th of June 2018 10:19:27 AM

EJP · Senior Member

Thanks Pariss, very interesting and informative video.

yobarr, I take your point on the WDH weight transfer issues. When I suggested that the weight increase on the front wheels could put excessive strain on the front axle and suspension components, I was referring to a vehicle already having exceeded its GVM, not a normally loaded vehicle. I don't think I was very clear. I conceed your point regarding increasing the trailer axle weight when using a WDH. I was, incorrectly, under the impression that the trailer axle weight remained the same when using a WDH. Apologies if I confused anyone.

Regards EJP

nswoutback · Member

The Police and or Road Authorities can read the plated / specified values for Gross Vehicle Mass, Gross Combination Mass, Ball Mass, Aggregate Trailer and Axle Ratings. These are fixed values on a particular vehicle. These values do not change when you load or unload a vehicle.

The Police and or Road Authorities may measure an individual axle load or several axles or all axles and compare these measured values against the respective Gross Vehicle Mass, Gross Combination Mass and Axle Ratings.

They may disconnect the caravan and measure the actual ball mass and compare this measured value against the plated maximum ball mass.

They may disconnect the caravan and weigh the whole caravan and compare this measured value against the plated Aggregate Trailer Mass.

When a weight distribution hitch is used, the following measured values will always change.

** The measured front axle weight of the motor vehicle will increase (maybe 70kg).
** The measured rear axle weight of the motor vehicle will decrease (maybe 100kg) which may reduce the actual weight to less than the specified maximum.
** The measured weight of the motor vehicle will decrease (maybe 30kg) which may reduce the actual weight to less than the plated maximum (GVM).
** The measured axle weight of the caravan axle / axles will increase (maybe 30kg).

Footprints · Senior Member

Please explain how a WDH can possibly add more weight to the front axle. The basic principle of levers would suggest that No extra weight is added however an additional load is added to the front axle which is a result of the leverage action of the WDH Creating a downward force. An additional load or downward force is quite different. A weight is constant ie add an accessory to the front of the vehicle where as the transferred downward force is variable when traversing in even ground.

nswoutback · Member

Footprints.

From your question, you clearly understand weight, mass, levers and force.

Most unlikely I can add to your knowledge on this matter but maybe someone else much wiser than I can.

Just to keep it simple.

When the front axle of a motor vehicle is standing on a weighbridge and the weight distribution hitch is tensioned up, the numeric value on the weighbridge readout increases. That is more than enough information for most folk.

yobarr · Guru

Footprints wrote:
Please explain how a WDH can possibly add more weight to the front axle. The basic principle of levers would suggest that No extra weight is added however an additional load is added to the front axle which is a result of the leverage action of the WDH Creating a downward force. An additional load or downward force is quite different. A weight is constant ie add an accessory to the front of the vehicle where as the transferred downward force is variable when traversing in even ground.

Hi Allan...As Andrew has said above,a weighbridge test will reveal the transfer of weight.I know nothing of the advanced terminology you use,but you can be assured that what we say is fact.Go to a weighbridge,van attached,and weigh the cars front axle.Now drive the whole car only,onto the weighbridge and note the weight.This gives the car GVM.Now reverse the rear axle of the car off the weighbridge,and tension the WDH.You will notice that the reading for the front axle weight has increased. Now drive the car back onto the weighbridge,and you will note that the GVM of the car has dropped,but by more than the weight increase on the front axle of the car.This is because a percentage (30%?,dependent on wheelbase of the car and the distance from the hitch point to the vans axle group) of the cars GVM has been transferred to the vans axle group. I have no doubt that all your advanced terminology makes sense to some,but the facts that I have outlined are,indeed,facts.The WDH effectively provides a stiff-arm from the front axle,through the hitch point,to the vans axle group.OK on a solid,flat surface,but you no doubt can imagine the ridiculous stresses applied to all components if the vehicle is used on corrogated roads,or even when accessing some servos.Sad,inconvenient truth. Safe and happy travels to all! Cheers.

-- Edited by yobarr on Tuesday 5th of June 2018 11:38:42 AM

rockylizard · Guru

Gday...

The ongoing total confusion about weights and how we comply - and the impact of loading and WDH on how we travel. confuse

A couple of years ago a 'weighing exercise' was carried out by a qualified VicRoads weighstation operator at a Gippsland VicRoads weighstation for caravanners information ... at no cost - or fines/penalties.

Have a look carefully at these two results from that weighing exercise. OH - and I have others.

Note - Actual Mass (no Tlr) line - for GVM, front and rear axle of vehicle.

Now - check Actual Mass with Tlr (no WDH) for GVM, front and rear axle of vehicle and GTM of van.

Now - check Actual Mass with Tlr (WDH) FOR GVM, front and rear axle of vehicle and GTM of van.

Weight 01.JPG

A WEIGHT DISTRIBUTION hitch does exactly that .... it DISTRIBUTES WEIGHT across the axles of the whole combination.

Cheers - John

-- Edited by rockylizard on Tuesday 5th of June 2018 12:06:09 PM

yobarr · Guru

rockylizard wrote:
Gday...
The ongoing total confusion about weights and how we comply - and the impact of loading and WDH on how we travel.
A couple of years ago a 'weighing exercise' was carried out by a qualified VicRoads weighstation operator at a Gippsland VicRoads weighstation for caravanners information ... at no cost - or fines/penalties.
Have a look carefully at these two results from that weighing exercise. OH - and I have others.
Note - Actual Mass (no Tlr) line - for GVM, front and rear axle of vehicle.
Now - check Actual Mass with Tlr (no WDH) for GVM, front and rear axle of vehicle and GTM of van.
Now - check Actual Mass with Tlr (WDH) FOR GVM, front and rear axle of vehicle and GTM of van.

A WEIGHT DISTRIBUTION hitch does exactly that .... it DISTRIBUTES WEIGHT across the axles of the whole combination.
Cheers - John

-- Edited by rockylizard on Tuesday 5th of June 2018 12:06:09 PM

Hi John......very comprehensive summary of the situation,which should help even our most ill informed (or misiinformed?) members understand the process. Safe and happy travels to all! Cheers.

-- Edited by yobarr on Tuesday 5th of June 2018 02:04:02 PM

PeterD · Guru

Footprints wrote:
Please explain how a WDH can possibly add more weight to the front axle. The basic principle of levers would suggest that No extra weight is added however an additional load is added to the front axle which is a result of the leverage action of the WDH Creating a downward force. An additional load or downward force is quite different. A weight is constant ie add an accessory to the front of the vehicle where as the transferred downward force is variable when traversing in even ground.

What does not change during the exercise is the mass of the front of the vehicle (or even the mass of the rear of the vehicle.) The weight on the front axle is what is measured by the scales. You can clearly see that the scale reading (the weight) changed as the van was hitched and and again when the WDH was applied. During the whole of the exercise the mass of load distribution in the vehicle did not change. I think you are getting mass and weight mixed.

-- Edited by PeterD on Tuesday 5th of June 2018 05:26:45 PM

Footprints · Senior Member

Peter, No confusion, I agree that the reading on the scales is unchanged however the point that i am making is that in a previous post it is stated that an increase in weight occurs on the front axle. If that is all that is required of the WDH why not just strap a couple of sandbags to the front of the vehicle to level the combination. It is Downward force applied to the front axle therefore increasing the load on that axle and that Load or Downward force is created by the leverage action of the applied WDH. Without a clear understanding of where the weights or specific loads are applied to the Tug and caravan it becomes more difficult to effectively and safely load both vehicles. Cheers

PeterD · Guru

Pariss wrote:
Hey Guys. Here is the definitive and correct answer to any WDH misconceptions some members have. Also, WDH ARE used extensively all over the world, particularly in the USA where Hayman Reece was invented. Cheers and enjoy the educational video. www.youtube.com/watch

Quote Footprints "No confusion, I agree that the reading on the scales is unchanged" I think the confusion is still there. Have a look at the Youtube video in the quote from Pariss above in this reply. You will see that the reading on the scales DID change. Unhitched the front axle weighed 4005 lb. When they hitched the trailer the weight dropped to 3925 lb. When the applied the WDH the front axle weight increased to 3650 lb.

yobarr · Guru

Footprints wrote:
Peter, No confusion, I agree that the reading on the scales is unchanged however the point that i am making is that in a previous post it is stated that an increase in weight occurs on the front axle. If that is all that is required of the WDH why not just strap a couple of sandbags to the front of the vehicle to level the combination. It is Downward force applied to the front axle therefore increasing the load on that axle and that Load or Downward force is created by the leverage action of the applied WDH. Without a clear understanding of where the weights or specific loads are applied to the Tug and caravan it becomes more difficult to effectively and safely load both vehicles. Cheers

Hi Allen....Your first post on this topic made me think that you had a better than average understanding of things,but subsequent posts make little sense,to me at least.Firstly,the purpose of a WDH is redistribute weight,and it does this by removing weight from the rear axle of the car,and transferring most of it to the front axle,with the balance being transferred to the vans axle group.The GVM of the car will decrease,and the GTM (and GVM) of the van obviously will increase.Total weight will stay the same,but the van will weigh more than it did before the WDH was tensioned.Obviously,the levelling-out of the combination is a by-product of the process.In days gone by,a WDH was primarily used to make the Kingswood and Viscount look a bit better so that no unwanted attention was attracted,but nowadays a WDH is primarily used to get weight off the rear axle of the car.To avoid offending the more sensitive souls on here,I will not name any particular model of car,but previous posts may give you up to 200 clues! It would seem that your rig is well set up,but many members seem to have little or no idea of their weights,and perhaps would welcome good advice?...Safe and happy travels to all. Cheers.