Bouncing when towing

[rambada]

Hi all
I have a Jayco Journey on the back of the D4 3.0 SE and as we drive it along it tends to bounce the rear end a bit. We had a hilux before with a smaller van and no issues so have some experience towing but not with air suspension.

The van has a measured and confirmed ball weight of 180kgs
There is nothing on the rear bumper bar
The van is about 2500kgs

So my questions are

Is this normal with the D4 airbag suspension?
Would a Mitch Hitch make any difference?
Its done 140k so would the rear suspension be tired? And how do you assess this? And what would need replacing please?
Is there some sort of set up Im not doing eg particular tyre pressures, etc?

Its got me perplexed.

[fitzy]

Sounds like the symptoms of worn shock absorbers/ dampers,
The traditional method to test is to remove and push down and check resistance

[scomac]

I always thought the life of a shock absorber/damper was around the 150km mark so depending on how much towing the vehicle has been doing, it may well be due for some.
Cheers
Scott.

[Graeme]

There's no rule for normal shock life because it depends on roads travelled, loads, speeds etc but by 140K the shocks are likely way past their useful life especially with 180kg bouncing on the tow-ball.

Hand operation of a shock cannot possibly be a valid test for worn shocks when normally there's 1.5 tonnes being damped.

[fitzy]

Hand operation will show up a well worn damper, any shocks that ive changed always have a marked difference in feel between old and new . Just my experience

[Tins]

It's not whether you can push them down. It's how they damp it back to stationary that you are testing for. However, there's no way I can do that test on my D2 with King Springs. Pedders do a cheap suspension test. Doesn't mean you have to but their stuff.

Bouncing is most likely the dampers, regardless of the type of car, but I"d also check you haven't got too much weight on the towball.

[rambada]

Other then OEM, is their a better dampner/shock absorber option? TIA.

[Tins]

Other then OEM, is their a better dampner/shock absorber option? TIA.

Oh, wow! He knows not what he asks!

Where's the popcorn?[bigwhistle][bigrolf]

[101RRS]

If you do a www search on pitching when towing you will find it has been reported quite a lot. My RRS does it and it has good shocks - you only notice when you haven't towed for a while and by the end of the trip not noticeable as you get used to it.

Yes can be shocks but I consider it to be an unwanted but not troublesome characteristic of the air suspension.

[Milton477]

The ball weight of my van is around 250kg & I can honestly say that I have not noticed any unexpected bouncing. Rear tyre pressures are normally around 45psi when towing. Undulations in the road will cause front to back pitching but this is normal to me. My D4 is a fair bit younger than your's though.

[DiscoJeffster]

Yeah I've never felt anything towing. I run 42psi in the rear when towing.

[RoverLander]

I tow a heavier van and with a ball weight of around 260kg and dont notice bouncing. Some possible things to try:

Are you using a weight distribution hitch? If so suggest you remove it as it is not meant to be used on a D4.

Ball weight is meant to be around 10% of the weight of the van. Your ball weight seems light for the weight of your van. Maybe try moving some heavy items forward in the van. Ball wight should be close to 280.

Do you have any significant weight on the very rear of the van. For example two spare tyres, tool boxes, outboard moters, generator? They may also cause bouncing (and sway).

thats my 2cents worth...

peter

[rambada]

Hi all and thanks for the replies

WDH - dont use them

Ball weight is what is on the van compliance plate. I've wondered if this is on the light side. Just not sure of the legal and insurance implications.

Nothing on the rear bar except 1 spare wheel, though I'd love to do more Im not gaim due to what was spoke of re increased pitching and yaw.

I'll do some more research on pitching but will talk it over with Rick (local LR service specialist). It could be all in my head which is what is holding me back from replacing the suspension. Silly to spend the $ when the result may not justify it and I could buy more toys....

[Pedro_The_Swift]

Ten percent BW is an urban myth,,
its just a very convenient number for van manufacturers to dodge engineering shortcomings.

and if its bouncing,, it has to be bad shocks,, [bigsmile1]

[ATH]

We only tow a light van with ours (about 1.8t guesstimate) and haven't noticed any problems. But when glancing through the handbook recently I did see that the distance between the pin holding the tongue in and the ball/spigot was shown as 150mm or 6".
Is this an important measurement does anyone know? It seems to be just for Australian vehicles.
AlanH.

[RobA]

We tow an AOR Quantum Plus with a down ball of 250kg and 2500kg tare for the van. We run around 2300kg fully loaded. The setup is very well balanced and we can fine tune that as we have JC at the F&R of the camper. Our car is only 2.5 years old so still fresh in the suspension. I suggest getting your down ball measured as well as taking a close look at weight distribution through your van to make sure it is low and evenly distributed. There are several excellent websites to help in this process.

Having moved from towing a 1000kg Ultimate I thought we would notice a large difference in handling but once you get used to the additional weight the car performs perfectly. Our fuel consumption has only gone up 2l per 100km which is where I hoped it would be

Rob

[BigJon]

As others have noted, at that sort of mileage I would be suspicious of the dampers.

[rick130]

Very rough rule of thumb is when you change tyres look at dampers.

Very little low speed (ie. under 4"/sec shaft speed) rebound and bump valving are often used for ride comfort, and it may be that the natural frequency of the air bags and maybe even the tyres is matched by the van towbar bobbing?

Unusual, but not unheard of.

I've had it once where we went right outside the damping range of some racecar shocks with the spring rates we were running.
The spring/tyre oscillations quickly escalated to the point the car bounced off the track.

[cjc_td5]

I noticed when on a trip recently, fully loaded but not towing, that the D4 would wallow after dips. It would fore and aft rock for one or two oscillations before settling down again. I put it down to the air suspension.

[DiscoMick]

As others have said, I would check your suspension was okay.
If it is then look at the weight balance of the van. A 180kg ball weight sounds a bit low for a 2600 kg van. If the ball weight is too low the van might be lifting up on bumps. I'm sure someone can describe that in more technical terms, but I hope you know what I mean.
Are your rear tyre pressures high enough for your towball weight?

[Celtoid]

Hi All,

I've had D4's since Jan 2010 but haven't towed anything of much weight until recently. Previously I was aware of clunk noises and movement which I assumed were just due to the (loose) connecting metal parts of chassis-LR kit-tongue and ball to trailer hitch. Other than that no issue.

I recently hired a twin axel (leaf sprung) Jayco Expanda that weighed about 2 T loaded. I'd changed wheels to my GOE 18s with 285/60/18 Cooper LTZs as I didn't trust the OEM Wranglers on gravel roads. I ran (according to my monitors) at 40 front and 45 back once everything warmed up ... those temps stayed stable regardless of surface or speed. It bounced quite a bit on anything but the best tar surface and my car has only done 40,000Klms ....so I'm not thinking shocks or air springs. It didn't affect the handling at all but was just a different feel to the car unloaded .... which I would have expected.

If that's not supposed to be happening, I'd say the van weight distribution or van suspension system is the issue. I guess unless you own the van you haven't got the option to experiment. At low ks I doubt it's the D4.

Kev.

[Melbourne Park]

I tow an AOR Matrix, which has a ball weight of over 250kg and the van is typically around 2300kg. My Disco late 2014 HSE has just clocked up 50k. Bought new, its towed the van less than 10k.

But I have noticed a sort of bouncing. It only happens on concrete roads. I presume its a sort of frequency of the way they pour the concrete roads. As soon as the concrete road goes, the bounce stops. It doesn't happen with every concrete road ... but I think concrete roads seem to have regular patterns of ridges or panels of flat and then another panel of flat - maybe the frequency is defined by a load of concrete. I don't know how they pour concrete roads.

But it shows that a Disco can get a sort of oscillation when towing. Speed doesn't seem to change the oscillation much either - but I have not really tested that.

I don't have LLams but if I did, I would play with the heights to see if that would make a difference - maybe lower the vehicle a bit ...

AOR say you need weight on the tow bar to ensure safe towing. 180kg on a 2500kg van doesn't fit AOR's formula - but I don't think the van is the cause, since mine sort of oscillates on several concrete roads.

If its happening on bitumen roads, I would be quite annoyed. Maybe tyre pressures would help, but somehow I doubt it.

I'm going to put a roo bar on my D4 - that might change the issue on concrete roads - but once again, I doubt it.

[DiscoMick]

This may be totally off target, but are your trailer brakes working OK? If not, the trailer could be pushing the vehicle.

[Celtoid]

This may be totally off target, but are your trailer brakes working OK? If not, the trailer could be pushing the vehicle.

Wouldn't that only occur if you were braking but not in the cruise?

[Ozzy119]

Whilst it could be Disco related I'd be investigating the Jayco suspension with interest. Literature outlines this van has 'new' Jtech designed suspension. Is it any good / why invent something to solve what exactly; when there are plenty of existing solutions?

I guess you could try using a mates tow vehicle and see what the van does. It's also interesting following vans, as you get quite a different perspective for whats going on.

[Pedro_The_Swift]

Its just another trailing arm setup,, but with a new name,, [bighmmm]

[wcody01]

Hi

I have a 2011 D4SE and use it to tow a 3.05 tonne 24 foot full size dual axel van. have been around Australia through the middle and even on the boat to 6 weeks in Tassie. I often use the airbag lowering and raising to hitch and un hitch which often gets looks and comments. I also tow a 14 foot dual axle car trailer on a regular basis.
Even after 270,000KM I don't see a problem with my shocks and haven't experienced any bouncing.
we do have a hefty ball weight often 300kg weighed at a weighing station. I do try to run 10% ball weight. it is industry standard.

perhaps before spending money on shocks it would be worthwhile loading u the front of the van. maybe a couple of drums of water on the a frame?????.... in a safe manner of course

just a thought. good luck

cheers
will

[GP1200]

Have been towing for quite a few years with both my old D4 and my current one ( 2013 with now 130,000 Km on the clock ) a double Jet Ski trailer with 2 x Ski's, a Jayco Swan ( with J Tech ) and now a 22 ft Jayco Starcraft ( with J Tech )

never had the bounce thing, I do get the occasionally sway with the big Starcraft if you overcook a corner by going to quick ( my fault, not the D4 or Caravan ), I would be seriously looking at how your weight in the van is loaded, I doubt very much it would be your D4.

I tow with standard D4 towing pack, my ball weight is around 250Kg with my new van, I haven't had it weighed yet fully loaded, but I suspect it will be something around 3.2 ton plus.

good luck
jack

[Pedro_The_Swift]

Hi

. I do try to run 10% ball weight. it is industry standard.

cheers
will


Yep,, the Caravan Industry standard,,

what does my mate have on his tag line??,,

tell a big lie, tell it often, advertise the **** out of it, and people will believe it,,


remember,, they dont build these things to tow---
they build them to make the centrefold of "Home Beautifull"
and then they just bolt 4 wheels on anywhere--
( oh yes they do-- to adhere to your 10 thing,,)

I'd love to read your Technical papers for 10%,,

Love to..

[Pedro_The_Swift]

and the worse thing about the stupid 10% rule?
They dont tell you its the MAXIMUM !!!!

no one EVER-ANYWHERE say 12% is ok,,

[Kandy]

Hi all
I have a Jayco Journey on the back of the D4 3.0 SE and as we drive it along it tends to bounce the rear end a bit. We had a hilux before with a smaller van and no issues so have some experience towing but not with air suspension.

The van has a measured and confirmed ball weight of 180kgs
There is nothing on the rear bumper bar
The van is about 2500kgs

So my questions are

Is this normal with the D4 airbag suspension?
Would a Mitch Hitch make any difference?
Its done 140k so would the rear suspension be tired? And how do you assess this? And what would need replacing please?
Is there some sort of set up Im not doing eg particular tyre pressures, etc?

Its got me perplexed.

Does it bounce all the time?
I tow about the same weight as you,rear tyre pressures are at 42, I have a McHitch set up and only 14K on the clock, so there is occasional bounce on rougher tarred surface but not alarming and as above you kind of get used to it (its not much bounce).
So I think its "normal", the hitch set up shouldnt make any difference, 140K could be an issue so check that out.

[RoverLander]

Yep,, the Caravan Industry standard,,

what does my mate have on his tag line??,,

tell a big lie, tell it often, advertise the **** out of it, and people will believe it,,


remember,, they dont build these things to tow---
they build them to make the centrefold of "Home Beautifull"
and then they just bolt 4 wheels on anywhere--
( oh yes they do-- to adhere to your 10 thing,,)

I'd love to read your Technical papers for 10%,,

Love to..

Not sure what technical paper would satisfy you?

Would you think ALKO may know a thing or two more about towing than you and I combined.

This is on their web site:
How to measure your trailer’s towball mass
Theoretical towball mass is calculated as ATM less GTM. However, the general rule of thumb is that it should be about 8 to 10 per cent of your fully laden trailer. Another indicator is the relationship between towing vehicle and trailer – ideally, both will be level while they’re coupled.


Towball weight scales: For heavier trailers and perhaps for those towing more often, towball weight scales will give a much more accurate reading.
Weighbridge: Sit your uncoupled trailer’s jockey wheel on a weighbridge with the wheels off the weighbridge. This is called ‘split-weighing’.

Here is the link: Understanding Tow Ball Weight | Without A Hitch (http://www.withoutahitch.com.au/trailer/understanding-towball-weight/)

...and Maybe Hayman Reece may know a few things as well?

How can I check my ball weight?Ball weight refers to the weight on the front end of the trailer not carried over the axles. As a rule you should aim to have 10 percent of the total trailer weight as ball weight. This can be measured at a weigh bridge by resting the jockey wheel only on the scale.
Alternatively Hayman Reese distributors have a Ball Weight scale with which you can measure your ball weight by placing it under the coupling and winding the weight off the jockey wheel.

Link: Frequently Asked Questions - Frequently Asked Questions - hayman reese (http://www.haymanreese.com.au/download/frequently-asked-questions#3)

I think aiming for around 10% is a good place to start with stability...but not the only factor,

[Melbourne Park]

Yep,, the Caravan Industry standard,,

what does my mate have on his tag line??,,

tell a big lie, tell it often, advertise the **** out of it, and people will believe it,,


remember,, they dont build these things to tow---
they build them to make the centrefold of "Home Beautifull"
and then they just bolt 4 wheels on anywhere--
( oh yes they do-- to adhere to your 10 thing,,)

I'd love to read your Technical papers for 10%,,

Love to..

Is this aimed at the trailer industry? I am not sure what your point is.

Australian Off Road make camper trailers for off road use and also off road caravans, and their owner recommends the Disco for a tow vehicle. Because he uses one.

As far as trailer loadings, they believe heavy weight on the tow bar is much safer. So they normally achieve a minimum of 10% of the trailer weight onto the tow ball.

My Disco does bounce though - on some concrete roads. It sort of goes up and down a bit ... quite strange. There seems to be a frequency from the rise and fall of the sections of concrete road. It happens rarely, but it has happened, and always on a concrete road.

But - the originator of this thread seems to have gone ...

[rambada]

Thanks all, been bush so internet intermittent at best.



Tyre pressures - I run them at 45-50psi rear and 40psi front following some other posts from this thread.
Tow ball weight - I've got a ball weight scale and measure as I change things around in the van - seems to sit 180 - 200kg. I haven't found any real definative regulation that says 'thou shalt not exceed the ball weight of the caravan' but am twitchy regarding potential insurance claims. Will look at upping the weight in a trial some time.
Could my brakes be grabbing on the van? Never thought of it so will investigate, though Im not quite sure how yet.
I've got it booked in at Pedders for a suspension check as was suggested, its in a weeks time so I'll report back what comes up.


Thanks for all the suggestions, will keep nutting it and report back.

[Milton477]

More random thoughts:

Is your D4 suspension calibrated to the correct heights?
Any chance you have an anti sway device fitted to the van that is maybe causing the brakes to grab?
When the back bounces, does the front of the car move in the opposite direction up or down?
180-200 ball weight does is not excessive & well within the 350 allowed.
Did you use a WDH with your previous setup? I have never used one but I am led to believe that it takes out some of the movement around the tow ball by stiffening the connection to the tow vehicle.


Good luck.

[Melbourne Park]

My late 2014 Disco - when its on some concrete roads - sort of goes up and down, both front and back together. It feels not smooth - sort of a soft jerkiness. Even when the mileage was at 10k, I felt it. So its not the shockers, or the trailer. It only happens on concrete roads too. And only on some of them. Hence I think its a sort of cycle like a harmonic, but with the suspension. If I had LLAMS I'd lower the vehicle and see if that affected the behaviour.

its so rare though that its not a problem.

[letherm]

FWIW this may not simply be a LR problem. A common thread here seems to be concrete roads. The phenomenon outlined reminds me of travelling along a long stretch of road on the northern NSW coast many years ago. The roads were concreted because of regular flooding and everyone's car bounced up and down over that stretch. Just my two cents worth.

Martin

[Melbourne Park]

FWIW this may not simply be a LR problem. A common thread here seems to be concrete roads. The phenomenon outlined reminds me of travelling along a long stretch of road on the northern NSW coast many years ago. The roads were concreted because of regular flooding and everyone's car bounced up and down over that stretch. Just my two cents worth.

Martin

Yeh ... A way around it would be to go a lot faster. Problem with that might be fuel plus a $400 fine!! Best to put up with it but fortunately, such concrete roads are not very common.

The complainant (thread starter) has not mentioned concrete roads though - its been myself that has mentioned the concrete roads. But I do know that I have had a vertical oscillation when towing, and its only happened on concrete roads, and also that its only been occasional concrete roads. I think there were some concrete roads going from Brisbane to Byron Bay ... I got some there (coming back towards Brisbane after the Blues Fest). Not on all sections of the concrete roads though. I am very aware of it - but my wife (who is in the front passenger seat) doesn't even notice its happening.

I could ask the Australian Off Road site for owners, and see if its happened to them - some of those guys travel huge distances. The only negative with doing so, is that the Land Rover is a bit unusual, and Toyota guys will have a big laugh ...

[DiscoMick]

There's an older section of the M1 at the Gold Coast where the concrete must have moved and we get some up/down when towing the camper trailer.

[rambada]

I know that concrete section well on the Gold Coast and Bermuda St is worse!! But they've shaved Bermuda street at last.

I get it on tarseal roads as well so not just concrete.
I've never used weight distribution devices previously or currently
Jayco have an ESC antisway but I declined it
Front of the car is stable but I had the front suspension done previously (?control arms - Ricks 4wd did it and I have total confidence in his work). So no wandering or being unstable.

I'll see what Pedders shows.

[rambada]

So for completeness of this query, Pedders didn't find much. Front lower ball joint and lower control arm bushes need replacing (I'd already had this done but will follow that up) and nothing for the rear end. They said due to the airbags they couldn't visually check the shocks so couldn't assess them but subjectively didn't find anything. I am going to follow this up with my usual service agent (Ricks) for a second opinion, needs a service anyway.

So now to experimenting with caravan weight distribution and tyre pressures. I thought I had it right and about even but Im going to try putting more weight forward. Thoughts behind this is maybe the air suspension needs that extra weight - dont know but just a thought. Then again, as I said, it could just be in my head.

Thanks for all the responses and ideas, if anything definative pops up I'll keep the forum informed.

[Milton477]

A very stiff/hard caravan suspension can cause the bouncing you are feeling. Some of the up & down movement of the van will be transferred to the hitch & onto the D4.
What pressures are you running the van tyres at & is the suspension in good condition?

[rambada]

Good thought - I have been running them around 50psi I think but I will drop them back. Suspension is fairly new - 18month old van with independent dual axles.

[Pedro_The_Swift]

Check the tyre's info,,
after watching lots ( as you do) other vans travelling I reckon most of the sway/bounce in modern vans is the tyre wall flexing,,
this is in comparison to an old school 14X75 LT tyre,, the off road tyres are designed to flex.

and anyway, your caravan tyre pressures will be dictated by their temp rise,,
took me 12months of record keeping to decide 50psi was just right,,

[RobA]

Stunned at running 50psi in a van? We run 44psi in our Q+ at 2500kg and not a problem. As well weight distribution can be a major contributor to poor towing experiences. Lots of web based information on this issue and your manufacturer should also be able to provide some specific guidance on CofG and weight distribution. Also recommend you get your down ball weight checked and if you can do the same when playing around with load distribution

Rob

[Milton477]

Just wondering if you solved your problem.

[rambada]

I haven't had the van out so I can't comment much. I've had Ricks 4WD on the Gold Coast have a look & they cant find anything.

So I'll try redistributing the weight and also tyre pressures. But only one change at a time to work it out.

The van compliance plate is approx 1850kg where the van is 2400kg, so using the 10% rule I can drop some more on the front end. From readings the van compliance ball weight is not legally binding but the insurance companies look at this should an accident occur. So I'll aim for just over the 2000kg mark I think.

As for pressures, I was pretty comfortable that 50psi was right from readings and on road. We did have it at lower pressures once and it felt as though we had more sway. I'll drop them down to 45psi and see if that makes a difference. I do run my car rear tyre pressures & the van (dual axles) all at the same pressure. And I aim for a 10psi difference between front and back when towing.

Thanks for the interest and follow up.

[rambada]

I've seen others comment on similar so I thought I'd post a follow up.

After much procrastination I installed a hi-rise hitch. And it made a world of difference. Cant recommend this highly enough.

I procrastinated due to price and the thought that how much can a few inches of higher tow ball height make. Just couldn't get my head around the value of bang for buck. I was wrong and it did make a significant difference so i would strongly recommend anyone towing a van or similar to consider this option.

One thing that I didn't realise, the tow ball sticks out a long way - just a heads up. Does make for easier reversing/hitching up.