Confused - D3/D4/RRS Towball Weight

[101RRS]

Since I have had my RRS I was under the impression that the max allowed towball weight was 350kg.

When reading my handbook this evening I was surprised to see that the actual tow ball weight is only 250kg.

So I then went into TOPIX and put in a D3 VIN so I could have a look at an Aust D3 handbook and it has an even lower tow ball weight of 150kg.

PDFs of relevant pages below.

What does your handbook say?

Confused Garry

[33chinacars]

My P38 was only rated at 150 kg. BUT Hayman Reece towbar only rated to 120 kg or 250 kg if the car didn't have ABS. So was stuck with 120 kg
Sorry but doesn't answer your question but manual says 250 kg ??
Gary

[Fatso]

Gday , there is a 350kg stamped on the tow hitch insert itself but can not see anywhere that the rrs can have 350kg on towbar .On page 200 of my book it says at GVW i can have 150kg ball weight , but if have a 250kg ball weight then i must reduce my GVW to compensate and keep to axle weight specks . Al

[Dougal]

Somewhere I read 350kg for Australian market only. I'll see if I can find it again. I was trying to work out at the time if the NZ market vehicles also got the 350kg rating.
But maybe that was 250kg. The brochures state 150kg for the euro style cast neck towball and adjustable height plate style tow-bar.

[wardh]

Hi Garry

On page 308 of my D3 owners hand book it clearly states under the page heading "Towing"

Nose weight at Maximum Gross Vehicle Weight [B]On-road 350 kg and Off-road 350 kg [B]

Hitch receiver also clearly stamped with the above rating

Cheers

Howard

[101RRS]

Hmm - as clear as mud.

The ball weight is the lesser of the manufacturers designated ball weight and the tow bar ball weight.

So if the cars tow ball weight is 250kg and the tow bar is 350kg then the allowable ball weight is 250kg.

I put in another VIN into TOPIX and looked at that vehicles Aust handbook and this one shows 350kg.

Garry

[TerryO]

But in Australia the vehicles tow ball weight, for a D3/4 anyway, is 350 kg so there is no issue.

cheers,
Terry

[Fatso]

Garry my previouse post was a bit wrong , on page 200 in my book it says that at GVW i can put 150kg on the ball but if i increase the ball weight to a max of 250kg then i must reduce my carrying load accordingly to maintain GVW . In all cases i can not exceed 1710kg rear axle load , bit confusing . I cant find 350kg ball weight anywhere in my handbook .

[101RRS]

But in Australia the vehicles tow ball weight, for a D3/4 anyway, is 350 kg so there is no issue.

cheers,
Terry

Who says it is?? Hence the question what does "your" handbook actually say.

The two D3 pdfs I have put up are from Australian Handbooks.

Garry

[Fatso]

Hand book says i can tow 3500kg and the tow hitch insert is rated 350kg , wonder if that refers to the tow weight and not ball weight , any way i think any load heavier than the tow vehicle is the tail wagging the dog .

[TerryO]

Well if it isn't 350 kg then I guess there will be a number of large and very expensive class actions against LR Australia and its dealers for providing false information to people who purchased D3/4's for the purpose of towing large vans.

I can remember asking a salesman at Trivetts when I looked at a new D4 about a year ago about the ball weight and he confirmed it was 350kg, so chances are everyone who has asked that question would have been told the same.

Lets wait and see until tomorrow when at least a few people who have read this thread ring and ask for written clarification on the Australian Tow Ball max weight for D3/4/RRS's to see what's actually correct.

My guess, this is a storm in a tea cup.


cheers,
Terry

[Graeme]

Whilst my D4 handbook has the 150 kg / 250 kg specs, it also has an "Australia only" section that states the nose weight can be up to 350 kg.

[101RRS]

My guess, this is a storm in a tea cup.


cheers,
Terry

Not a storm just a conflict of information.

The Australian Handbook should list the correct information but seems to vary between 150kg to 350kg - certainly not consistent.

In legal terms if there is an accident - who will authorities believe - the dealer told me it is 350kg or the official Landrover Handbook which says 250kg or whatever.

I would just like to know what is the correct figure - the handbook supplied with my car says 250kg not the expected 350kg.

Garry

[THE BOOGER]

I dont own either a d3/4 or a rrs is it right to compare them as according to the sheets garry linked to they have different max rear axle loads as well as tow ball weights the RRS is less than the d3/4?:)

[Graeme]

In legal terms if there is an accident - who will authorities believe - the dealer told me it is 350kg or the official Landrover Handbook which says 250kg or whatever.
In your position I would quote the dealer's 350kg and would not produce a version of the handbook that says otherwise. The handbooks for the latest RRS may be similar to the D4 handbook which states 350kg for Australia. Someone with a current model RRS might like to check their handbook for you, even sending you a copy of the relevant page to insert into your handbook.

[stray dingo]

Whilst my D4 handbook has the 150 kg / 250 kg specs, it also has an "Australia only" section that states the nose weight can be up to 350 kg.

As does mine.
With the proviso that once GVM is reached, it drops to 150kg.

As cross reference, the Vehicle Towing Mass Guide (May 2011 version) lists D3 & D4 as 350kg Max, with sub-note of 'GVM & Axle loads not to be exceeded'
(RRS has an extra sub-note of 'Must be a minimum of 7% of the Aggregate Trailer Mass up to a maximum of 350kg. If the ball mass exceeds 150kg, adjust the interior load so as not to exceed the axle loads.')

Is there a label on the car anywhere to advise - my old Nissan used to have one on the drivers door, but I can't find anything obvious on the D4??

[101RRS]

Thanks for that link - I guess the issue is using generic Handbooks for vehicles is the issue. My handbook does not have an Australian supplement but I see on Topix that later VINs do have a Supplement dealing with Aust towing..

So I guess the 350kg tow ball limit is it if it is in supplements.

Thanks for all the input.

Cheers

Garry

[Redback]

Thanks for that link - I guess the issue is using generic Handbooks for vehicles is the issue. My handbook does not have an Australian supplement but I see on Topix that later VINs do have a Supplement dealing with Aust towing..

So I guess the 350kg tow ball limit is it if it is in supplements.

Thanks for all the input.

Cheers

Garry

That's the case regardless of the vehicle, because your ball weight is included in your GVW, in the casr of the D3/D4, Tare is 2480, GVW is 3240, which gives you 760 load max, take 350 off that, leaves you your max luggage carrying ability.

To confuse matters, the D2 is different again, to tow at the max for it at 3500 and 250 ball weight, no luggage is allowed, only a passeger, and as you reduce the tow weight, an increase of luggage weight is allowed.

Baz.

[Fatso]

Just wondering if anyone is using a 350kg ball weight , been thinking about this as it is an enormus omount weight to be hanging off the back of any normal 4x4 vehicle , some scarey facts , 350kg can = some of the following , 350lts or 77gallons of water ,:eek: just imagine nearly 2x200 ltr drums sitting on your towball , 771 pounds , or a third the weight of a Hyundi Getz the mind boggles. this can not leave much usable carrying capacity for any thing much else !! :confused: . Would hate to have to leave the beer behind .

[Dougal]

It appears to be the tongue which is the limiting factor.
Aus/NZ got the receiver for the square tube, it has "350kg max" or something like that cast into it.

The long tongue with a ball on the end I imagine would have some lower rating cast in, but I have yet to see one in person.

350kg is about 7 strong people to lift the trailer off the ball.

[THE BOOGER]

Some people believe you must have 10% of the trailer weight on the towball for it to tow correctly so a max tow weight of 3500kg means 350 kg on the ball:o

[Dougal]

Some people believe you must have 10% of the trailer weight on the towball for it to tow correctly so a max tow weight of 3500kg means 350 kg on the ball:o

Rule of thumbs are seldom right and bloody hard to retract after decades of use.

[Redback]

Some people believe you must have 10% of the trailer weight on the towball for it to tow correctly so a max tow weight of 3500kg means 350 kg on the ball:o

It's really only a guide, it's recommended that it be 7% to 15%, of coarse this will depend on your load, why put 350kg on the ball with a 3500kg van, me personally I'd be trying to keep it under 200kg.

My camper is 1500kg, my ball weight is 65kg, I know it's not heavy, but still I have no problems being under the "rule of thumb"

Baz.

[THE BOOGER]

Yep 350 is a lot personally I try and keep it at a weight i can lift :)

[Glynhouse]

Last time I weighed my ball weight it came in at 380kgs, nearly had a fit ! I new it was heavy but that was ridiculous. The 80 series with a WDH had handled it with no problems, 18ft van but now known to have a heavy ball weight, and not only mine. ( van comes in at around 2.6 to 3000kgs)
I suspect that I have got it down to around the 300 mark, anyway the D3 had no problem with it over Easter, but was not fully loaded for an extended trip.
Will weigh it before we take off again.

DD

P.S. You think some of us have a problem ? look at this one, brand new ball weight too high and it is on the market ! ball weight 436kgs !!

2011 28 FT CUSTOM BUILT ISLAND STAR OPAL CARAVAN | Caravan & Campervan | Gumtree Australia Charles Sturt Area - Seaton (http://www.gumtree.com.au/s-ad/seaton/caravan-campervan/2011-28-ft-custom-built-island-star-opal-caravan/1001779081)

[Glynhouse]

Referring to the van in the above link, it was "custom built" who designed something with that ball weight ? and what is anyone going to do with it ?

Probably convert it to a fifth wheeler for well under $10k, would be a cheap unit at that, I can't think of anything else you could do with it. probably come it at around 3500kgs all up.

Not my cup of tea !

DD

[rufusking]

All those lower ball weight limits relate to the EU type tow attachments. See attached image.

[Lotz-A-Landies]

Last time I weighed my ball weight it came in at 380kgs, nearly had a fit ! I new it was heavy but that was ridiculous. <snip>You need to re-position some of the gear inside the van to balance it a little better.

Moving one 20Kg box from the front of the van to behind the inter axle mid point could take 40Kg off your towball weight.

[discotwinturbo]

Just wondering if anyone is using a 350kg ball weight , been thinking about this as it is an enormus omount weight to be hanging off the back of any normal 4x4 vehicle , some scarey facts , 350kg can = some of the following , 350lts or 77gallons of water ,:eek: just imagine nearly 2x200 ltr drums sitting on your towball , 771 pounds , or a third the weight of a Hyundi Getz the mind boggles. this can not leave much usable carrying capacity for any thing much else !! :confused: . Would hate to have to leave the beer behind .

So far so good. 345kgs with a triple axle horse float at 7metres in length. Almost always attached to the car. Vw toaureg also towed this with factory springs, but used a wdh.
Have ordered a Mitch hitch today, so will need a hitch to go back down to the low level needed to keep the float level. Mitch hitch is perfect for the camper, but very high for the float.
Have been worried about the structural integrity of the LR hitch....apart from other things such as brake switches.
Brett.....

[Lotz-A-Landies]

Some people believe you must have 10% of the trailer weight on the towball for it to tow correctly so a max tow weight of 3500kg means 350 kg on the ball:oYou do need a positive forward balance to keep for towing stability but it there is no rule in physics that requires it to be 10%.

With car floats, I always position the load so the trailer comes level and then move it slightly forward so I can see the weight come on the tow vehicle. I do this even if the load is not up to the loading board and then secure the 4 wheels to the deck where they are.

The number of cars you see on trailers with the load right on the loading board, the tow car dragging its bum and steer almost off the road is frightening. It is made worse when you see the amount of space behind the load car that could have been used to re-balance the trailer.

Its a bit harder to do that with horse floats, but caravans it's merely a case of moving heavy things from one end to the other. If you uncouple the van and it wants to tip up at the back its bum heavy, you should have enough weight forward so it wants to drop down to the front and can be lifted relatively easily by two blokes or by one average person with some effort.

[Tryanything]

It's really only a guide, it's recommended that it be 7% to 15%, of coarse this will depend on your load, why put 350kg on the ball with a 3500kg van, me personally I'd be trying to keep it under 200kg.

Baz.

So a 3.5 tonne van being towed by a 2.5 tonne 4wd with a 5.7% (200kg) tow ball load? Please let me know what stretch of road you are on cause I will steer clear thanks.:p

Seriously, there is a actually bit of theoretical physics and experimental evidence behind the towball load recommendations. Too low and the rig will likely snake, too high and it will be more stable 99% of the time but could jacknife without warning.

Personally, I would not tow anything exceeding the weight of the loaded D3 (before towball load is addd), and even then would keep it below 90km/hr.

[Dougal]

So a 3.5 tonne van being towed by a 2.5 tonne 4wd with a 5.7% (200kg) tow ball load? Please let me know what stretch of road you are on cause I will steer clear thanks.:p

Seriously, there is a actually bit of theoretical physics and experimental evidence behind the towball load recommendations. Too low and the rig will likely snake, too high and it will be more stable 99% of the time but could jacknife without warning.

Personally, I would not tow anything exceeding the weight of the loaded D3 (before towball load is addd), and even then would keep it below 90km/hr.

Do you know more about towing than the engineers who apply design vehicles around tow ratings?

[Tryanything]

No I dont. But I have researched this subject quite a bit (too much probably) before I bought my D3 because of all the scare mongering around about the Landrovers not being able to use a weight distribution hitch.

Given my plan is to use my new D3 for towing duties with my family on board I have obviously concluded that the inability to fit a WD hitch is not a problem. In fact I found quite a bit of evidence to suggest that the common practice of using a WDH to "relevel" the tow vehicle will lead to much higher chance of the tow vehicle oversteering at quite low cornering forces.

However, I did come across quite a lot of research which suggests that a towball load as low as 5.7% is not good for sway stability, and it is really not a good idea to tow a van which is materially heavier than the tow vehicle. Instability can occur as low as 100km/hr and the outcome can be nasty.

It has been proven that there is a marked difference in how a towing combination performs depending upon van characteristics such as its yaw inertia, cornering stiffness of its tyres, distance from tow hitch to van axle and of course towing speed.

These van related factors are obviously outside the control of the LR engineers and I can't speak for what they assumed when they calculated a load rating of 3.5T and 350kg ball load. But I can tell you that in general, a van weighing nearly 1.5 times the tow vehicle mass, with just 5.7 % towball load will have a MUCH lower stability threshhold speed.

The attached slide was prepared by Richard Klein, an SAE contributor and Automotive Engineer of more than 30 years experience in the field, who has pretty much dedicated his professional life to the study of trailer towing instability. His response when I mentioned a 2.5 tonne vehicles towing 3.5 tonne van at speeds approaching 100km/hr was that that was "VERY dangerous".

I do believe HE knows more about towing stability than the LR engineers...

[slug_burner]

What assumptions about the trailer drawbar length have been made to produce that graphic?

[Tryanything]

Not sure, and there are a number of other assumptions that have been made about the vehicle and van. You will see the notes actually say that each combination will have a somewhat different result. But I've read research papers by Richard which have considered eveything from family sedans to large US made pickups and the general conclusions remain the same - be careful with towball load and avoid towing vans materially heavier than the tow vehicle.

From what I have read a longer drawbar ( or longer distance between hitch point and van axle) would have the effect of moving the lower diagonal line to the left ( ie it has a favourable effect on sway stability).

[slug_burner]

And to move the upper diagonal to provide more stability:

Increase the wheelbase of the tow vehicle;
Reduce the distance between rear axle and the towball;
Increase stiffness of tyres by raising pressures or use LT tyres for increased sidewall stiffness, and

I am sure that suspension stiffness would also play a part.

[Tryanything]

Spot on. Although I think those things also help with the lower line as well.

Also any sloppiness in the steering will also hurt it as well as it reduces the effective cornering stiffness of the tow vehicle.

From what I can tell the upper diagonal is associated with loss of understeer of the tow vehicle. Research on this refers to it as divergent instability, meaning instability happens abruptly with no warning signs (jack knife). This can happen if the rig receives a side load at speed such as a passing truck or road defect.

The lower line is the snaking/oscillatory instability which can start at quite low speeds and gets progressively worse with speed until the natural damping of the rig is overcome (since damping is being reduced by speed whilst at the same time the sway forces are increasing).

In both cases, speed is the enemy.

[gghaggis]

The term "typical" in the attached slide and notes gives a fair bit of leeway. The EAS LR, being a dynamically suspended vehicle, is not typical when compared to a static suspension system and its unsprung mass. Hence the non-requirement for WDH's. There is no drooping of the rear axle under load and the associated assumption of a constant spring rate.

I'd imagine that in this application, yes - the LR engineers probably know more. They have some reasonably qualified automotive engineers working for them you know. Regardless, it's a bit of a strawman issue - LR do not indicate that 5.7% towball load is ideal.

Cheers,

Gordon

[Dougal]

No I dont. But I have researched this subject quite a bit (too much probably) before I bought my D3 because of all the scare mongering around about the Landrovers not being able to use a weight distribution hitch.

Given my plan is to use my new D3 for towing duties with my family on board I have obviously concluded that the inability to fit a WD hitch is not a problem. In fact I found quite a bit of evidence to suggest that the common practice of using a WDH to "relevel" the tow vehicle will lead to much higher chance of the tow vehicle oversteering at quite low cornering forces.

WDH's are something I would never use either. Fine if you only travel on flat land with no corners, but a serious concern if you involve hills and/or sharp corners.



However, I did come across quite a lot of research which suggests that a towball load as low as 5.7% is not good for sway stability, and it is really not a good idea to tow a van which is materially heavier than the tow vehicle. Instability can occur as low as 100km/hr and the outcome can be nasty.

Are you aware that heavy trucks tow heavier trailers with the only nose weight being the weight of the drawbar?
Stability is about the entire vehicle and trailer interaction, it cannot be expressed in simple percentages as it is far more complex than that.
Zero ball weight can be perfectly safe and stable, where trailers with the often touted 10% static ball weight can be a danger to everyone.



It has been proven that there is a marked difference in how a towing combination performs depending upon van characteristics such as its yaw inertia, cornering stiffness of its tyres, distance from tow hitch to van axle and of course towing speed.

Don't forget axle/suspension configuration. It's one of the biggest in trailer stability.


The attached slide was prepared by Richard Klein, an SAE contributor and Automotive Engineer of more than 30 years experience in the field, who has pretty much dedicated his professional life to the study of trailer towing instability. His response when I mentioned a 2.5 tonne vehicles towing 3.5 tonne van at speeds approaching 100km/hr was that that was "VERY dangerous".

I do believe HE knows more about towing stability than the LR engineers...

Unfortunately that slide alone means nothing. If you were to include the SAE paper the presentation was about and the full power-point presentation then perhaps we could draw some conclusions. Such a graph can only beproduced relating to a specific case and we have no information about that specific case.

[GeorgeK]

Hi Everyone,

I don't think I will or can contribute to a very technical debate. All I can say is that I have a 2010MY Disco 4 HSE that I bought new and now has about 53,000 kms under its wheels.

About 28,000 kms have been towing a tandem axle 3500kg van. The van is about 24' external body for a total of about 30' all up. (measured from front of hitch - the pointy end to the rear of the spare wheels hanging off the rear bumpers). The ball weight has realistically varied between 330kg and 380kg depending on where I have weighed the van and what loads I have on board. Clearly when the ball weight is over 350kg I rebalance the load.

I am very careful to try to keep the heavy cargo and van furniture e.g. fridge low in the van and balanced over the axles. I don't use WDH and I have the standard LR plough hitch (the hitch works very well).

I am very careful to drive to the prevailing road conditions. My optimum open road speed is about 95kph. This is my optimum for my comfortable driving and best fuel economy.

My wife and I are really enjoying the lifestyle and thoroughly recommend it. My Disco has not missed a beat and is a very very comfortable drive.

Cheers

George:)

[Tryanything]

Are you aware that heavy trucks tow heavier trailers with the only nose weight being the weight of the drawbar?
Stability is about the entire vehicle and trailer interaction, it cannot be expressed in simple percentages as it is far more complex than that.
Zero ball weight can be perfectly safe and stable, where trailers with the often touted 10% static ball weight can be a danger to everyone.

Don't forget axle/suspension configuration. It's one of the biggest in trailer stability.

Unfortunately that slide alone means nothing. If you were to include the SAE paper the presentation was about and the full power-point presentation then perhaps we could draw some conclusions. Such a graph can only beproduced relating to a specific case and we have no information about that specific case.

Are the heavy trucks you are referring to much heavier than the trailer they are towing? Is the hitch point hanging off the back of the truck or between the axles? Does the trailer have two well spaced axles? If none of these answers are yes, then I doubt the rig would be at all stable at near 0 % ball load.

Axle/suspension config - yes you are right, both their cornering stiffness and their damping have a big effect

SAE paper/presentation- I dont have permission to post them publicly but can forward a copy to anyone interested if they PM me.

In general I agree with the sentiment though that the actual cutoff points and instability lines would be specific to a particular rig.

[Dougal]

Are the heavy trucks you are referring to much heavier than the trailer they are towing? Is the hitch point hanging off the back of the truck or between the axles? Does the trailer have two well spaced axles? If none of these answers are yes, then I doubt the rig would be at all stable at near 0 % ball load.

Yes, trailers several tons heavier than the towing truck and load.
Yes hitch point well over a meter behind the centre of the rear axle group. Legislation here limits rear axis to tow-coupling at a maximum of 45% of the wheelbase.
Trailers from two axle rigid to 5 axle (3 rear axles, two on the dolly).

Close to zero ball (ring-feder) load. Only the drawbar weight is possible and these are sprung to sit level with no truck attached for ease of attachment.

Here is just one example:
https://www.aulro.com/afvb/images/imported/2012/06/926.jpg

Setups vary, but at the 44t max combination weight (without getting into overweight permits) the loaded trailers are about 4t heavier than the loaded trucks. Primarily because dimensions work out to greater load space in the trailer.
The official New Zealand road code for heavy vehicles - Information for heavy vehicle drivers (http://www.nzta.govt.nz/resources/roadcode/heavy-vehicle-road-code/information-for-heavy-vehicle-drivers/heavy-combination-vehicle-types.html#simple-trailers)

I am very interested in information on that SAE paper.

[Dougal]

I figure this is a good time for this landrover promotional video.

I'd estimate the towed load at
2.3t of defender 110
700+kg of trailer.
So there is an easy 3 ton.

I can't recall whether the downforce on the hitch shown is 150 or 250kg. Either way, the nose load is a lot less than the 350kg spoken about here.

Land Rover&#39;s "Trailer Stability Assist" for Range Rover, Range Rover Sport and Discovery 4/ LR4 - YouTube

[Tryanything]

The analysis work I have seen done is for trailer setups where there is only one axle, or two close together near the centre of gravity. Trailer setups where there is an axle near each corner as per the photos are inherrently more stable.

[Tryanything]

I dont doubt the effectiveness of trailer stability programs on vehicles such as the D4 to improve stability. In fact I found a research paper for that too ( though not specifically for the D4 program). http://delphi.com/pdf/techpapers/2008-01-1228.pdf


Would be interesting to see how the D4 handled that rig with the trailer stability switched off?

Dougal - Ill try to send you a copy of the other papers by pm

As for those who are towing a very heavy van, the only warning I would give is that lack of oscillation is not necessarily an indication of stability. In general higher towball loads % will reduce sway oscillations, but as shown on the slide I posted it can lead to what is referred to a different kind of instability (divergent instabiliy), which is not associated with oscillation and can occur without warning if the rear tyre slip angles get too high ( due to for example a sudden side force)

[gghaggis]

I'm missing the point you're trying to make? The PDF paper is a second order approximation for articulated vehicles. What are you trying to state w.r.t. towing with less than 10% towball weight for a D4?

Cheers,

Gordon

[discotwinturbo]

My touareg with the wdh is a superior ride towing our 3.5 tonne triple axle horse float then my airbag equipped D4....period.

It is much harder to set up, and much harder to disconnect, with the toaureg, but the D4 is not as stable as the touareg with this kind of weight.

Even my wife picked up on the difference....and it's very noticeable on uneven road surfaces. Less pitching and wallowing compared to the D4. The touareg would be a good couple of hundred kilos lighter.

I was not expecting the D4 to be as stable, but closer, though it is a darn sight easier to setup and disconnect.....and for this reason alone we use the D4 more for heavy towing now.

Brett....

[Tryanything]

I'm missing the point you're trying to make? The PDF paper is a second order approximation for articulated vehicles. What are you trying to state w.r.t. towing with less than 10% towball weight for a D4?

Cheers,

Gordon

Gordon

I paper I attached was in response to the post about the D4 active sway control using tow vehicle brakes. Thats what the paper deals with and concludes that it can help.

It does also show the effect of towball load on the stability of the rig. In particular, it considers a vehicle weighing approx 2.7 tonne towing a trailer of approx 1.2 tonnes. It considers three towball loading cases, one at 10.8%, one at 2.8% and one at -8.8% (ie tail heavy van).

It then calculates and verifies through testing using a vehicle and test trailer, the speed at which the Damping Ratio becomes negative. (Damping Ratio is simply a measure of how big subsequent sway movements are compared to an initial sway introduced by a steering movement for example). A bigger damping ratio means the sway movement diminishes quicker, a damping ratio of zero means the sway neither gets bigger nor smaller, and a negative damping ratio means the sway oscillations increase in size - ie kiss your tush goodbye.

It concludes that the vehcile with 10.8% towball load has a critical speed ( speed at which damping ratio becomes negative) >160km/hr. For 2.8% towball load, critical speed is 105km/hr. For -8.8%, you're toast at 72km/hr!

Ok so 2.8% towball load is a bit less than the 5.7% which was originally suggested, but the paper also highlights that the critical speed drops as the mass of the trailer increases relative to the vehicle mass.

So given the test was done with a vehicle of about he weight of a disco, (2.7 tonne), but with a 1.2 tonne trailer, I dont think towing a 3.5 tonne trailer with a 5.7 % towball load would be very safe ( especially if you dont have the D4 trailer stability program! I wish my D3 did!)

I have other papers on the subject of trailer stability and they deal with towball load amongst other factors, but as I mentioned they are materials which have been provided to me directly by the author and are otherwise only available for purchase via SAE.

Hence I cannot upload them but am happy to send to those interested, provided they commit to not further distributing them.

Regards
Scott

[gghaggis]

Brett:
Never towed with a Touareg, so can't directly comment - but I have with a LC200 + wdh, and the RRS was far more stable at high speed.

Scott:
The info is interesting, but I don't see the relevance to a D4 - which is not an articulated vehicle?

I don't believe that a D4/RRS would have significant problems towing 3 tonne as long as there was some reasonable towball weight. What "reasonable" is seems to be the issue here - rule of thumb is around 10%, and it would appear that LR automotive engineers design around this figure. There doesn't seem to be any evidence that 6% or so is _not_ safe when considering a twin-axle caravan of this weight on the back of a D4, all other things being equal.

Cheers,

Gordon

[Glynhouse]

I do not know the technical side of this debate, I have held a road train license (110 tone 4 trailer) and have done over 150K towing a 3 tone van behind an 80 series and now a D3.
I have missed the point entirely on the comparison of a van to the other trailers mentioned ?

My 80 with a WDH on a bad road - plenty up here in FNQ - pitched far less than the D3, however was nowhere near the tow vehicle that the Disco is, however we have not done enough mileage to give a definite opinion on the D3. I feel I would be happier with a WDH but am not using one but I see quite a few that do on air suspended L/R, D3/4's, they are also quite happy using them.
As far as ball weight goes we have done quite a bit of travell in both the states and the U.K. and find it is only Aust. that has this 10% figure, last year in the U.K.we did over 5000 miles in a hired M.Home and most vaners that we camped with all worked on under 5%, and they pull 20/24 ft van with cars that we would not dream of using as a tug, the vans a lot lighter than ours though.
In the states we saw a lot more large heavy vans than we expected, thought they might be predominantly 5th wheelers, saw no more than half a dozen WDH's in use in 2 months.

A long ay to say I basically agree with Gordon.

DD

[discotwinturbo]

Brett:
Never towed with a Touareg, so can't directly comment - but I have with a LC200 + wdh, and the RRS was far more stable at high speed..

Cheers,

Gordon

no wdh reqd for the D4 was one reason we chose it over the 200.

Not sure why it is, but virtually every 200 I see that uses a wdh, still drags it backside....maybe they are not tensioning it correctly.

The vw and the disco are perfectly the same as they were without the trailer.

Bett....

[Tryanything]

My touareg with the wdh is a superior ride towing our 3.5 tonne triple axle horse float then my airbag equipped D4....period.
Brett....

Brett
When you use the WDH do you tension it until the touareg is restored to level? If so, then Whilst it might feel better for minimising pitching, the vehicle is likely to have lost most if not all of its original understeer bias and would be likely to oversteer at side loads ( eg cornering) of >0.3g. (Note that 0.3g would still feel very fast for cornering with a van attached, but even cornering at slower speed with a coincident side load (passing truck, wind etc) could get you there.

Apparently ( again according to papers I've read), the WDH should only be tensioned to restore approx 25-50% of the load lost on the car's front axle when the trailer is attached. Compare this to "levelling" which restores well over 100% of the original front axle load.

[Tryanything]

Brett:
Never towed with a Touareg, so can't directly comment - but I have with a LC200 + wdh, and the RRS was far more stable at high speed.

Scott:
The info is interesting, but I don't see the relevance to a D4 - which is not an articulated vehicle?

I don't believe that a D4/RRS would have significant problems towing 3 tonne as long as there was some reasonable towball weight. What "reasonable" is seems to be the issue here - rule of thumb is around 10%, and it would appear that LR automotive engineers design around this figure. There doesn't seem to be any evidence that 6% or so is _not_ safe when considering a twin-axle caravan of this weight on the back of a D4, all other things being equal.

Cheers,

Gordon

Gordon, "artculated vehicle" (in the context of the paper) is simply a car towing a trailer. If you look at the diagrams later in the paper you will see it is exactly the setup you would use for either single or dual axle caravans.

As I mentioned earlier, the tow vehicle they examined was the same mass as a D4, but the trailer only weighed 1.2 tonne and they concluded you are in good shape with 11% towball load, but unstable at 105km/hr with 2.8%.

A heavier trailer reduces the damping, and lowers the critical speed. I would be surprised if a 3.5 tonne trailer would be stable up to 100km/hr with a 6% towball load and no dynamic trailer sway control.

[discotwinturbo]

Brett
When you use the WDH do you tension it until the touareg is restored to level? If so, then Whilst it might feel better for minimising pitching, the vehicle is likely to have lost most if not all of its original understeer bias and would be likely to oversteer at side loads ( eg cornering) of >0.3g. (Note that 0.3g would still feel very fast for cornering with a van attached, but even cornering at slower speed with a coincident side load (passing truck, wind etc) could get you there.

Apparently ( again according to papers I've read), the WDH should only be tensioned to restore approx 25-50% of the load lost on the car's front axle when the trailer is attached. Compare this to "levelling" which restores well over 100% of the original front axle load.

I had it tensioned by a hayman Reese engineer who was in Perth for a show....he was a friend of my dad.

It's almost the same height without trailer at the rear. He had me weigh the car without trailer, with trailer without wdh and then with wdh at settings until we got it right. The weight was about 45/55 distribution with front being 45%.

Have had to do emergency braking on a couple of occasions over the years and all brakes on vw performed like they were designed, plus the trailer bakes have been set perfectly....it stopped quick as the front brakes could also perform their best.

The vw performs better then the D4 towing this weight with the wdh...cornering, braking, and comfort.

But it has been set up right, which I reckon very few would set it up this way.

Brett....

[gghaggis]

Gordon, "artculated vehicle" (in the context of the paper) is simply a car towing a trailer.
Ah yes, my error .......


As I mentioned earlier, the tow vehicle they examined was the same mass as a D4, but the trailer only weighed 1.2 tonne and they concluded you are in good shape with 11% towball load, but unstable at 105km/hr with 2.8%.

You presumably have some other source for that statement? The paper you're quoting concludes that the primary drivers of dynamic instability are the relative positions of the trailer centre-of-gravity and the normal load of the trailer axle(s). The variation in towball load is a consequence of that, but the precise figures will be specific to the dimensions of their test trailer (draw-bar length, distance-to-axles, weight distribution etc), so you cannot use this particular simulation to generalise the case for towball load. As Glynhouse said above, different towball loads aren't necessarily "dangerous", although I think we'd all agree that a negative load would be rather precarious!


I would be surprised if a 3.5 tonne trailer would be stable up to 100km/hr with a 6% towball load and no dynamic trailer sway control.
I'd be surprised if anyone towed 3.5 tonne at 100kph with a car! At least the D4 _does_ have dynamic trailer sway control (asymmetric braking), so you have less chance of a runaway condition.

Cheers,

Gordon

[Tryanything]

You presumably have some other source for that statement?

Gordon

No - not really necessary. The statement I made is just a summary of the conclusions drawn directly from the paper. The towball loads and trailer weight are all stated explicitly so the tow ball percentages I quoted are obtained by simply dividing one weight by the other. Apologies if I am misunderstanding where you see the problem??

Don't get me wrong, I'm not suggesting that the specific numeric conclusions from the paper are valid for all trailer/vehicle combinations. And I'm not for a moment suggesting I have all the answers in such a complex area, I definitely don't. In fact, many on this forum ( such as yourself) would have WAY more practical experience with towing and particularly Landrovers than I ever will.

Given I have already benefited from advice from others on this forum, I guess I was just trying to contribute something back in an area I have spent a fair bit of time researching.

Like many others, I had always thought the 10% towball load guide had no basis in engineering/physics, but I discovered that in general, it does, as this and other research demonstrates. But this rule of thumb does oversimplify the real learning with all this which is that there is a towball % weight range over which a rig will be most stable. If the towball load goes too low, the caravan will oscillate/sway and do so uncontrollably over a certain speed. Likewise, if the % towball load is too high, it makes the tow vehicle itself unstable leading to oversteer/jacknife.

In both cases, having a trailer much heavier than the tow vehicle substantially lowers the speed at which the instability can occur. This is the whole point of the orginal slide by Klein I posted.

Personally, I have taken what I have learned from this desktop review of available research on board when setting myself up for towing. Others can form their own view.

[gghaggis]

I guess my point is that (from what I read) you're calling the "cart" the "horse". Nowhere does the author specify that the towball load is the causal agent. Rather, the COG/axle-load positional ratio is the driver of instability. And from that, with the specific dimensions of a particular caravan you could (possibly) calculate ideal towball load. Did they do a separate experiment with towball load as the primary variable?

It seems 10% of total trailer mass is a good "guestimate" for being in the ballpark for an ideal COG/axle-load positional ratio, but it's quite possible that 5%, for a particular van, or 15% for a different one, would also be within the stable ratio range. Lacking all the sensors required to monitor all the dependent variables, the best thing one can do is try it. Don't necessarily panic if you towball mass is _not_ 10% of the caravan mass.

Cheers,

Gordon

[Pedro_The_Swift]

Just as an devils adcocate example ,,
With my 2.2T D2(wheelbase is smaller than a D3/4) I tow a 18' 1.7T 4-wheel independent Van,
When I first brought it home, I weighed everything--

I have a ball weight of 70kgs,,

The van was built in 1990.

Tows like a dream,,
no sway from passing semi's,
in fact no sway at all--!
http://www.aulro.com/afvb/discovery-2/80040-show-us-your-d2-79.html

no, its not an add--;)

[THE BOOGER]

Pedro what page or post number is yours:)

[Dougal]

Gordon, "artculated vehicle" (in the context of the paper) is simply a car towing a trailer. If you look at the diagrams later in the paper you will see it is exactly the setup you would use for either single or dual axle caravans.

As I mentioned earlier, the tow vehicle they examined was the same mass as a D4, but the trailer only weighed 1.2 tonne and they concluded you are in good shape with 11% towball load, but unstable at 105km/hr with 2.8%.

A heavier trailer reduces the damping, and lowers the critical speed. I would be surprised if a 3.5 tonne trailer would be stable up to 100km/hr with a 6% towball load and no dynamic trailer sway control.

So towing a 3 ton trailer (vehicle on dual axle trailer) with a ball load of less than 200kg (estimated off the rear spring rate and compression) would be deathly unstable according to this paper and your own thoughts?

Because I've done just that with my RRC, perfectly stable and I may have even broken 100km/h on part of the journey. Trip included hills steeper than you'll find in Australia and plenty of corners both up and down-hill.

Why is there a big disconnect between the predictions and reality here?

[Tryanything]

Hard to say. Certainly 3 tonne is better setup than 3.5 tonne. It could be that your vehicle/trailer has some attributes favouring better stability ( shorter hitch overhang, lower yaw inertia, longer distance between hitch point and trailer axle).

I guess there will always be exceptions.... but I dont think this undermines the science. Just like the existance of a 98 year old smoker does not make smoking safe.

[Dougal]

Hard to say. Certainly 3 tonne is better setup than 3.5 tonne. Could be your vehicle/trailer has some attributes favouring better stability ( shorter hitch overhang, lower yaw inertia, longer distance between hitch point and trailer axle).

I guess there will always be exceptions.... but I dont think this undermines the science. Just like the existance of a 98 year old smoker does not make smoking safe.

I don't think my vehicle has anything special towing wise. The only real difference over all the other RRC's built since 1970 is a heavier diesel in the front.

I think the research you are touting is over-conservative to the point where it appears irrelevant. More like the 16 year old smoker than the 98 year old smoker.

Certainly I have only ever witnessed one unstable trailer and it had everything wrong. I was lucky that it bounced the other way as it passed me.
1. Loose coupling (agricultural pin and eye with probably 15mm slop).
2. No trailer suspension (balloon tyres not rated for the speed).
3. Single Axle.
It hit a bump downhill while accelerating from a 50km/h zone to a 100km/h zone while I happened to be driving the other way. As luck would have it I knew the driver too and helped him roll his trailer back onto the wheels. He didn't make it to 100km/h, probably only 70. If he'd stayed under 50 he'd likely be okay. At 40km/h guaranteed safe.

But the trailer was much lighter than the towing vehicle (around 400kg max) and the nose weight would be around 10%. Of course when everything else is wrong, adhering to one rule of thumb ain't much help.

[Tryanything]

It could also be that you just haven't yet encountered a sufficiently large sideways disturbance, at a high enough speed to trigger instability.

Vehicle safety is built around engineering, not anecdotes. As I mentioned earlier, personally I trust the engineering, but everyone inevitably needs to make their own choice, conservative or otherwise. Just a shame that we sometimes have to live with the consequences of others choices.


Scott

[THE BOOGER]

Have a read of this

http://outbacktravelaustralia.com.au/doc/TO-TowballWeightsTrailerStabilitySTA.pdf

In real world tests (bath university) apparently 6-8% works best I suspect not everybody will agree:angel:

[Dougal]

It could also be that you just haven't yet encountered a sufficiently large sideways disturbance, at a high enough speed to trigger instability.

Well it handled safely and smoothly all the hills with uphill and downhill corners at the speeds which I wanted to drive them. It's not the only time I've towed such a load. Certainly such loads are routinely seen on the roads here.
All of this negative evidence suggests the weapons of mass destruction may not exist.



Vehicle safety is built around engineering, not anecdotes. As I mentioned earlier, personally I trust the engineering, but everyone inevitably needs to make their own choice, conservative or otherwise. Just a shame that we sometimes have to live with the consequences of others choices.

Scott

Indeed, I am an engineer and I make a living working within the laws of physics. I am just not seeing the problems this guy is suggesting in the small amount of his work you have presented.
At the extreme cases, these problems certainly do exist. How big are the safety factors applied in his graphics?

My experience suggests the biggest single factor in how a vehicle tows is the suspension setup. The setup of landrover suspension (particularly their early coil spring and beam axle designs) has several advantages and I beleive this is why they have historically held a far higher tow rating than comparable vehicles with leaf springs and other coil-spring configurations.
This is also why IMO (and others opinions) why landrover engineers know more about landrover tow ratings than engineers in other fields trying to apply a best fit using data obtained from completely different vehicles.

[Tryanything]

Bristol study: Very familiar with that work. In fact that was the first bit of research I came across.

The work was sponsored by Bailey caravans in the UK and they have used the findings to refine their caravan design. The UK market generally have lighter weight caravans with lower yaw inertia. They need to because the typical tow vehicle is not a LC or landrover but a family sedan. The limiting factor for stability in this case is actually the GVM and axle load for the tow vehicle so they necessarily favour a lower towball load, and offset this with superior van stability characteristics mentioned above.

[101RRS]

Hey guys - the reality is that the RRS/D3/D4 is cleared to tow 3500Kg and a max ball weight of 350kg. We know the rule of thumb is ball weight about 10% but between about 5-15% is "ok". We are talking about a tow point behind the rear wheel - not a B double or a 5th wheeler.

I am not sure the minutia that is being put up is all that helpful to us ordinary people.

Garry

[Tryanything]

Well it handled safely and smoothly all the hills with uphill and downhill corners at the speeds which I wanted to drive them. It's not the only time I've towed such a load. Certainly such loads are routinely seen on the roads here.
All of this negative evidence suggests the weapons of mass destruction may not exist.



Indeed, I am an engineer and I make a living working within the laws of physics. I am just not seeing the problems this guy is suggesting in the small amount of his work you have presented.
At the extreme cases, these problems certainly do exist. How big are the safety factors applied in his graphics?

My experience suggests the biggest single factor in how a vehicle tows is the suspension setup. The setup of landrover suspension (particularly their early coil spring and beam axle designs) has several advantages and I beleive this is why they have historically held a far higher tow rating than comparable vehicles with leaf springs and other coil-spring configurations.
This is also why IMO (and others opinions) why landrover engineers know more about landrover tow ratings than engineers in other fields trying to apply a best fit using data obtained from completely different vehicles.

Hey dont make me out to be a Landrover basher! If I didn't think a Landrover was the best towing vehicle out there after my research than I wouldnt have bought one a week ago for the purpose of taking my family on a caravaning holiday!

Re suspension: yes it is a factor, and bad suspension ( low cornering stiffness) can make a big difference.

"Small amount of work" as basis for conclusions?: well all I can say is I have read about 5 papers which all conclude that trailer weight to tow vehicle ratio, location of CoG, and speed are all critical factors in stability.... And I have been discussing the subject at length with the author of the papers listed below (Dick Klein) over the past month or so. Not my work - just sharing the conclusions of others.

DOT Reports
*
1.​Handling Test Procedures for Passenger Cars Pulling Trailers. Vol I: Summary Report, Vol II: Technical Report, Vol III: Appendices. NHTSA DOT HS-801-935, 936 and 937. June 1976. NTIS: PB-256 071, 072, 073.
*
2.​Effects of Weight Distributing Hitch Torque on Car-Trailer Directional Control and Braking, NHTSA DOT HS-803 246, 1977.
*
3.​Development of Car/Trailer Handling and Braking Standards. *Vol. I: *Executive Summary. *Vol. II: *Technical Report for Phase I - Rear Wheel Drive Tow Cars. *Vol. III: *Appendices for Phase I. *Vol. IV: *Technical Report for Phase II - Front Wheel Drive Tow Cars, NHTSA DOT HS-805 326, 327, 328 and 329, Nov. 1979.
*
4.​Recommendations for DOT HS-802 586 Additions to DOT/NHTSA Travel and Camper Trailer Safety Booklet, DOT HS-802 586, Aug. 1980.
*
SAE Papers
*
A.​Effects of Trailer Hook-up Practices on Passenger Car Handling and Braking, SAE Paper No. 780012, Feb. 1978.
*
B.​Determination of Trailer Stability Through Simple Analytical Methods and Test Procedures, Systems Technology, Inc. P-233, SAE Paper No. 790186, Feb. 1979.
*
C.​Development of Maximum Allowable Hitch Load Boundaries for Trailer Towing, SAE Paper No. 800157, Feb. 1980.
*
D.​Description and Performance of Trailer Brake Systems with Recommendations for an Effectiveness Test Procedure, SAE Paper No. 820135, June 1982.
*
E.​Crosswind Response and Stability of Car plus Utility Trailer Combinations, SAE Paper No. 820137, 1982.
*
F. * * * * Lateral/Directional Stability of Tow Dolly Type Combination Vehicles, SAE
* * * * * * Paper No. 960184, Feb. 1996.
*
G. * * * *Sway stability of 5th Wheel RV Trailers, SAE Paper No. 2012-01-0237, Feb.

[Tryanything]

Hey guys - the reality is that the RRS/D3/D4 is cleared to tow 3500Kg and a max ball weight of 350kg. We know the rule of thumb is ball weight about 10% but between about 5-15% is "ok". We are talking about a tow point behind the rear wheel - not a B double or a 5th wheeler.

I am not sure the minutia that is being put up is all that helpful to us ordinary people.

Garry

Very fair point - my apologies to all.:angel::oops2:

If anyone does want any further info/discussion, pm me as I'm happy to share what I have learned.

[101RRS]

No need to apologise - a lot of interesting stuff has been put up - a bit like discussing the whys and wherefores of terrain response in D3/D4s - some just select what the terrain dictates where others what to know the detailed working of the systems.

Cheers

Garry

[Dougal]

Re suspension: yes it is a factor, and bad suspension ( low cornering stiffness) can make a big difference.

Not stiffness, suspension geometry. Specifically roll-centres.
The roll-stiffness of landrover suspension is historically very low, this is why they work so well off-road.



"Small amount of work" as basis for conclusions?: well all I can say is I have read about 5 papers which all conclude that trailer weight to tow vehicle ratio, location of CoG, and speed are all critical factors in stability.... And I have been discussing the subject at length with the author of the papers listed below (Dick Klein) over the past month or so. Not my work - just sharing the conclusions of others.

Yes, small amount of work. You have only shown one powerpoint slide in this thread. The rest has been paraphrasing.

[TerryO]

Actually Dougal I don't believe that your 100% correct, stiffness of suspension can make a real difference when towing, when I first had new Koni shocks fitted to the D3 it towed our van incredibly well at any speed even on tight and twisty country roads.

But it would seem the shocks were doing most of the work and within about 6 thousand kilometres all four shocks were stuffed and leaking. Koni has since replaced them with a new batch that has different dampening and they are far more compliant. With the first set there was no body roll with either a van on the back or not while cornering, now the D3 with the new shocks has plenty of body roll and doesn't handle anywhere near as well.

While I am yet to tow our van with the new shocks I bet when I do it will not be as pleasant an experience. Koni it would seem changed the dampening so as to take some of the strain off of the shocks, I bet these ones last a lot longer than the first set. But it is at the cost of handling and stability.

Once I get to tow our van I will report back on how it handles with the new shocks but I'm not expecting much.

cheers,
Terry

[Dougal]

Actually Dougal I don't believe that your 100% correct, stiffness of suspension can make a real difference when towing, when I first had new Koni shocks fitted to the D3 it towed our van incredibly well at any speed even on tight and twisty country roads.

I know stiffness makes a difference, I didn't claim otherwise.

I stated the geometry of the suspension makes the single biggest difference and is the reason most landrovers tow better than other vehicles of similar dimensions while having softer suspension.

[away]

This thread is of great interest to me. I tow a well known brand of off-road van that should weigh-in at 3500 Kg with 350 Kg on the ball. I found out, on our last trip, that these figures were complete BS and it wasn't all to do with how the van was loaded. Before I publish what the real weights were I'll give you a quick insight into what happens when a manufacturer builds and weighs their vans for the compliance plate.

Our van was built to carry two gas bottles, to carry 240 litres of water (160 litres of which is forward of the axles), built to carry a 2 KVA generator that was included in the price, has an extended drawbar so that a bicyle rack could be fitted (for two bikes), designed with the bed up front (where the largest stowage area is), built with two jerry can holders up front and designed to have three x 120 AH batteries in the front boot.

The reality is that the van is weighed without water, with only one gas bottle filled, without the generator stowed, without the bike rack fitted, no jerry cans equipped, no water or luggage on board. Like this, it apparently weighed a total of 2840 Kg, with the ball-weight not being specified.

I dutifully weighed everything that I put into the van (including filling the empty gas bottle) and have for years towed that van around thinking that I was legal.

Imagine my surprise when, on a whim, I weighed the car/van combo at a public weighbridge on our return from holiday, and found that the van was 330 Kg over - but worse still, the ball weight was 650 Kg!!!

I always knew that the bugger was heavy, just by the time it took the air suspension to re-level once the van was lowered onto the vehicle - but never did I think that it was so heavy.

Anyway, the vehicle actually handled this weight with great ease, surprisingly, and has been doing so for almost four years. To fix the issue we are selling the bikes and removing the rack, selling the generator that we never use anyway (and along with that will go the jerry can of fuel), relocating one of the 80 litre water tanks to behind the axle, removing almost 100 Kg of tools, oils, coolants and spares that we have been carrying around in the front boot of the van and relocating the batteries behind the axles (under the seats of the lounge.). This will solve both the weight and the weight distribution issues but will mean that we will have to go without some things that we once thought were necessities.

Without moving the water tank aft of the axles (and filling it to provide an 80 Kg counterbalance), we would NOT be able to achieve the legal ball weight for the vehicle (even with the batteries relocated), so the van manufacturer fudged something in the original weigh-in.

The reason I am posting this little self-confession is to express how thankful I am that the Disco's allowable ball-weight is 350 Kg and more to the point, that it was able to safely handle a bloody sight more.

Cheers

Russ

[gghaggis]

Glad you're sorting it - at 650kg ball-weight it would be easy to exceed the rear axle load limit!

Cheers,

Gordon

[~Rich~]

Hi Russ, good write up on your experience.
What hitch do you have?
Standard / Mitchell hitch?

[Summiitt]

This has been an interesting topic with a lot of technical info, thanks.If your weights are set up correctly, then the biggest single factor in safe towing has to be your driving style and driving to the conditions. This is only an example, but I regularly,(and legally) tow a 22.5 ton trailer behind a truck weighing 12.5 ton, with a ball weight of 3.5 ton. I change my driving style depending on the road, the weather, and the traffic, my point is, regardless of the load, size of your trailer, and weight distribution, drive to the conditions, commonsense I guess should prevail!

[Graeme]

Glad you're sorting it - at 650kg ball-weight it would be easy to exceed the rear axle load limit!

...let alone the towbar rating!

As LR's published max ball weight elsewhere in the world is 250 kg, I suspect the Oz 350 kg limit is to allow a 3.5T tow limit along with a 10% max rule somewhere in the ADRs.

[Dougal]

...let alone the towbar rating!

As LR's published max ball weight elsewhere in the world is 250 kg, I suspect the Oz 350 kg limit is to allow a 3.5T tow limit along with a 10% max rule somewhere in the ADRs.

Suggest you read the previous four or so pages.

[wcody01]

intersting reading. a few cirlces and roundabouts leading to the same spot in there
one question maybe a little off the topic but still relevant

I tow a 24' 3.0 tonne van without any WDH behind our 2011 Disco4 sdv6. absolutely love it. have had TSA activate twice. once accelerating up hill around a bend overtaking other vehicles (perhaps too heavy in the foot) and another in a bed with a dip that unsettled the vehicle and van. both times the TSA kicked in before i had had time to react and corrected the issues.

But to my question.
what is the standard rear axle wieght? I am not asking whatthe rear axle is rated to but what is the basic standard rear axle weight so i can then add my storage boxes, water, down ball weight to ensure i do nto go over the rating? I have found the rear axle rating in my hand book but no where does it have the basic standard rear axle wight (that i can find)

Hope someone can help
(also hope people are still in this thread as it has been a while since the last post)

Cheers
Will

[gghaggis]

There are no published figures I can find, and it would depend on how each individual vehicle has been spec'd up. Presumably it would have to be less than half the unladen mass of the car. Best thing to do is use a weighbridge and get the exact figure for your car.

Cheers,

Gordon

[mowog]

Doh...

[wcody01]

That's what i have found also, that there is no published figures.
so as much as we talk of documented weights, balances and legalites, we all have to go back to phiscially weighing our vehicles to ensure we are within the guidlines of safety.
Unfortunately weighing a vehicle is not as easy as getting the scales from the bathroom.
That freind who owns his own weigh bridge just became a much better freind....

Cheers
Will

[gghaggis]

I'd counter that blithely using some published figure to calculate your safety margin, that doesn't include that rear A/C you fitted, or the entertainment pack, or the eLocker etc etc, is the worse offence. Public weighbridges don't cost much. Use them.

Or for a minimal figure, take half the vehicle mass (Mowog's "doh!"), subtract from max rear axle load and use that, knowing that there is a reasonable safety margin.

Cheers,

Gordon

[mowog]

I posted and forgot to engage my brain when typing... So Doh....!

[wcody01]

Perhaps what is needed is more training followed my more regulation enforcement when it comes to weghts and loads.
having said that as part of that enforcement should also come easy accesability to tools such as weigh bridges. perhaps this should be funded/supplied by the relevant registration authorities in eahc state ie RTA, Vic roads etc. We all pay enough in taxes and registrations that this sort of facility should be readily availible and not cost the earth.
Drivers (maybe not the converted and interested in this forum) irresponsibly drive around with 6.5 - 7 tonne combinations with no training or education on the effects of those loads. I personally am sensitive to this, we used to tow our 3 tonne van with a mitsubishi triton.... which demanded all things be right.
could write more of a novel but war and peace this is not

Cheers
Will

[NutoLR]

Who says it is?? Hence the question what does "your" handbook actually say.

The two D3 pdfs I have put up are from Australian Handbooks.

Garry

Garry,

For my 2008-09 TDV8 page 189 of the manual indicates that nose weight "Must be a minimum of 7% gross trailer weight, up to a maximum of 350kg. This is under the heading of Australia Only. (whole section from Topix)

However, I am not sure if this can be correctly interpreted as LR condoning a 350kg ball weight for an RRS, or that is a statutory limit for (this class) of vehicle provided it doesn't exceed the manufacturer's specification?? BUT, it doesn't actually say that!

Of course, as others have noted the 3500kg stamps are all over the hitch and tongue. but I think it only confuses the issue. So I have taken the 250kg ball weight as the practical maximum. When you think about it, an actual 350kg ball weight would very seriously limit what else you can carry in the vehicle.

FYI, I have attached the entire Towing section of the manual.

Cheers,
John ...

[TerryO]

Hello John,

Re the specs from the manual of the minimum ball weight of 7% and.a max of 350 kg. I would think that these are LR's own specifications. The 10% ball weight everyone talks about is not set in law it is just an accepted and now recommended ball weight.

I'm sure someone will correct me if I'm wrong but I have never seen or heard of another vehicle manufacturer who stipulates a certain percentage of a trailers/vans weight be applied as the minimum ball weight.

Thanks for putting that up, more than likely just proves that most of us don't but should read the information supplied by the manufacturer.

Cheers,
Terry

[weeds]

just loaded up and drive off i say........thats probably what 90% of us do

why, just about nobody goes to the trouble to weigh there rigs and trailers......i have a weigh bridge at work and although i have weighed the defer i haven't weighted my complete setup

[NutoLR]

Hello Terry,

I think may be you are right; on reflection you'd think that LR wouldn't make any reference at all to an Australia-only 350kg ball weight max if they weren't prepared to back that specific variation (to 250kg limit).

Cheers
John

[NutoLR]

Hi Garry,

The RRS towing PDF I posted last night was a Topix download. However, I have just checked my physical handbook and can advise that the relevant page is identical to the Topix download.

Cheers
John

[mowog]

I have weighed my van and worked out the ball weight and I come in at 320kg. The van is 3500kg in full travel trim with water tanks full.

You often hear people say they would never tow at the vehicles limit... The limit is there because its a limit and the specs say you can tow those weights. I have towed this van around 15000klm without any issues except that my rear shocks are now below par. They are being replaced under warranty.

[Dougal]

You often hear people say they would never tow at the vehicles limit...

Do these same people never drive at the speed limit?:angel:

[mowog]

Do these same people never drive at the speed limit?:angel:

They are most likely ones with an LC 200 with a 16' van doing 70 to save fuel.

[TerryO]

I have weighed my van and worked out the ball weight and I come in at 320kg. The van is 3500kg in full travel trim with water tanks full.

You often hear people say they would never tow at the vehicles limit... The limit is there because its a limit and the specs say you can tow those weights. I have towed this van around 15000klm without any issues except that my rear shocks are now below par. They are being replaced under warranty.


Agreed limits are just that limits and I too see no issue with going to the limit otherwise why buy a full size 4x4 if you can't tow a 3.5 ton van with the accepted 10% ball weight.

cheers,
Terry

[Fatso]

My two bobs worth !!
350kg on the ball and 3500kg draging :eek: is just too much weight for any 4x4 to be realy safe on the roads :no2: , these sort of weights need a lite truck of some sort.

[101RRS]

My two bobs worth !!
350kg on the ball and 3500kg draging :eek: is just too much weight for any 4x4 to be realy safe on the roads :no2: , these sort of weights need a lite truck of some sort.

It would seem Landrover and a lot of other manufacturers disagree.

[Pedro_The_Swift]

just loaded up and drive off i say........thats probably what 90% of us do

why, just about nobody goes to the trouble to weigh there rigs and trailers......i have a weigh bridge at work and although i have weighed the defer i haven't weighted my complete setup


The very first thing I did after dragging it home was weigh it,,
and the car,,

[bcl]

My two bobs worth !!
350kg on the ball and 3500kg draging :eek: is just too much weight for any 4x4 to be realy safe on the roads :no2: , these sort of weights need a lite truck of some sort.

And is this a professional opinion?

[Fatso]

And is this a professional opinion?

Nah, just a common sence one !!

[mowog]

Nah, just a common sence one !!

You are entitled to your opinion on this. But I can tell you a 3500kg caravan is no issue for a D4. Brakes/Engine/Suspension are all up to the job. I have towed this van a lot on bad and good roads and there has never been anything to indicate any issues.

However a much lighter van 2300kg did have issues being thrown about on bad roads bad enough to cause the trailer stability control to activate. On the same roads the 3500kg van just tracked and stayed where it was supposed to be.

[ADMIRAL]

Let's keep opinions civil. The manufacturers are under massive pressure to list high tow ratings. Their sales depend on it. This leads to dangerous variations, like the current Prado. The SWB has a greater tow rating than the LWB. Toyota deem the chassis on the SWB can take the higher load rating. No doubt it can, but now you are towing 2700kg behind a vehicle the size of a glorified Rav.
IMO, regardless of what a manufacturer lists, it makes sense to me that towing anything heavier than you are, decreases the safety margin available to the driver. Your call.

[Dougal]

Let's keep opinions civil. The manufacturers are under massive pressure to list high tow ratings. Their sales depend on it. This leads to dangerous variations, like the current Prado. The SWB has a greater tow rating than the LWB. Toyota deem the chassis on the SWB can take the higher load rating. No doubt it can, but now you are towing 2700kg behind a vehicle the size of a glorified Rav.
IMO, regardless of what a manufacturer lists, it makes sense to me that towing anything heavier than you are, decreases the safety margin available to the driver. Your call.

2.7T behind a prado is about the same as 1.5t behind a family car. With the appropriate trailer, loading and driver I don't see the problem.

[Stuart02]

Let's keep opinions civil. The manufacturers are under massive pressure to list high tow ratings. Their sales depend on it. This leads to dangerous variations, like the current Prado. The SWB has a greater tow rating than the LWB. Toyota deem the chassis on the SWB can take the higher load rating. No doubt it can, but now you are towing 2700kg behind a vehicle the size of a glorified Rav.
IMO, regardless of what a manufacturer lists, it makes sense to me that towing anything heavier than you are, decreases the safety margin available to the driver. Your call.
Does it not also depend on suspension set ups, drive train strength etc?

[gghaggis]

Does it not also depend on suspension set ups, drive train strength etc?

Most definitely - prime movers haul many times their own weight all the time, but they're set up specifically to do this.

Cheers,

Gordon

[TerryO]

2.7T behind a prado is about the same as 1.5t behind a family car. With the appropriate trailer, loading and driver I don't see the problem.

The only problem is a Prado can only tow 2.5 ton legally. :wasntme:

cheers,
Terry

[discotwinturbo]

Terry,

Short wheelbase prado can tow 3 tonne. Makes no sense that a shorter wheelbase, and less weight can tow more.

Less is more.....some say.

Brett....

[Dougal]

Terry,

Short wheelbase prado can tow 3 tonne. Makes no sense that a shorter wheelbase, and less weight can tow more.

Less is more.....some say.

Brett....

If they are limited to the same gross combination weight, then the lighter vehicle gets to tow more.