Sway: Landrover TD5 (airbag suspension) VS 1983 Evernew (single axle)

Submitted: Friday, Mar 29, 2013 at 12:13
ThreadID: 101368 Views:2081 Replies:8 FollowUps:8
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During our recent 19,000km lap of the west half of Oz I often experienced disturbing amounts of van sway, particularly where the bitumen road surface was slightly rutted by heavy vehicles.

I've had wide ranging and well intended advice about WDS, anti-sway devices, car and van tyre pressures, optimal ball-load etc. Currently we don't have WDS or anti-sway devices, the self levelling suspension seems to work well and the rig sits nice and level

I know the issue has had a flogging in the past but is there anyone out there who has experience with fixing sway with a rig like ours?
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Reply By: MEMBER - Darian, SA - Friday, Mar 29, 2013 at 13:15

Friday, Mar 29, 2013 at 13:15
I'd be putting the van's suspension into consideration - a wild thought here is that maybe the old suspension geometry on the van is unsympathetic to the relative space age suspension on your tug.....new firmer springing might be the go (any shocks on the van at present ?). Readings here and there on road safety suggest that its only a short jump from 'disturbing van sway' to 'arghhhhhhh'.
AnswerID: 507798

Follow Up By: GH35 - Friday, Mar 29, 2013 at 17:01

Friday, Mar 29, 2013 at 17:01
Thanks Darian,
I think you are on the money, the springs are 30 years old and saggy, plus the Disco tends to sail its own course a bit, so the combination might well be the problem.
No shocks on van.The "short jump" is what concerns me!!
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FollowupID: 785099

Follow Up By: Member - Legendts - Friday, Mar 29, 2013 at 19:25

Friday, Mar 29, 2013 at 19:25
I would also go with the suspension as the first port of call if you want to keep the van, or it's a good excuse for a new one :-). Either way I would bet the van is the issue.

LR do not recommend using a WDH on them.
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FollowupID: 785110

Follow Up By: MEMBER - Darian, SA - Friday, Mar 29, 2013 at 22:05

Friday, Mar 29, 2013 at 22:05
Whatever you do van wise, it would pay to weigh the loaded van first then check the ball weight - with those figures, a spring maker should be able to supply something ideal - if you could tap into any van-industry suspension/chassis makers you might get the best advice going. I dropped in to a spring maker years back on Port Road Hindmarsh (SA) to get my boat trailer springs re-rated (up) - was cheaper to supply new ones - they were not expensive.
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FollowupID: 785118

Reply By: Thinkin - Friday, Mar 29, 2013 at 13:55

Friday, Mar 29, 2013 at 13:55
(1983 Evernew), looks like it has a few years under it's belt.
Is it all original, no extra watertanks, additional boxes front or especially the rear.
Any of these additions could affect weight distribution, therefore handling problems.

Alpero.
AnswerID: 507800

Follow Up By: GH35 - Friday, Mar 29, 2013 at 17:03

Friday, Mar 29, 2013 at 17:03
Alpero,
The van hasn't any major additions, or at least none at the ends. I fitted a battery just in front of the axle. All heavy stores are stowed close to the axle line.
Geoff
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FollowupID: 785100

Reply By: fisherPete - Friday, Mar 29, 2013 at 14:39

Friday, Mar 29, 2013 at 14:39
I had a similar problem with a tail heavy boat and fixede it by moving the axle back 25mm.
Cheers Pete
AnswerID: 507803

Reply By: Ross M - Friday, Mar 29, 2013 at 16:18

Friday, Mar 29, 2013 at 16:18
GH35
What tyres are on your van? Are they narrow in width and haven't enough tread to grip the ground and therefore will very easily side slip a little . Then it will get the sways up.

What dia, section width/aspect ratio and tread style are they?
Are the tyres older and harder and can't grip because of the hardness?

IF you do have shock absorbers they may not be working to dampen the oscillations and since the towing vehicle probably has good shock they will be tight and terrific and the van can be sloppy and loose.

So, tyres and suspension control are possibly the issue. One or the other or both.

Ross M
AnswerID: 507811

Follow Up By: GH35 - Friday, Mar 29, 2013 at 17:10

Friday, Mar 29, 2013 at 17:10
The van has 195 R14 light truck tyres that were replaced just before the trip. I played with the pressures from 40-60psi without a lot of noticeable difference.
No shockies fitted so the old saggy springs probably contributing to the problem. The Disco tends to wander a bit as well making things worse.
Maybe time to make the jump to a new van!!
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FollowupID: 785101

Follow Up By: Ross M - Friday, Mar 29, 2013 at 18:24

Friday, Mar 29, 2013 at 18:24
GH35
How far is the tow ball from the rear axle of the vehicle.
IMHO some of the modern hitches have the ball much further away from the rear axle than is necessary.
Is it possible to modify the tongue or hitch or whatever you use so it improves this critical distance and makes it more favourable?

I have redrilled a number of tongue units to reduce the caravan/trailer telling the vehicle what to do. Any control the caravan has over the vehicle is then magnified as the vehicle wanders a bit and the caravan then wags behind.

This distance may be the reason the Landrover is not feeling stable.

To me 195R14 isn't a substantial tyre in todays terms and a larger rim dia but wider lower profile tyre may be better if it all fits.
The typical tread on a light truck tyre isn't what you would call grippy at all and so may not hold side forces very well when most required.. May take the load but not perform.

The shocks and tyres and the tow bar ball position are all factors worth a close look and a bit of analysis to determine where the issue lies.

Ross M
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FollowupID: 785106

Follow Up By: Peter 2 - Friday, Mar 29, 2013 at 21:19

Friday, Mar 29, 2013 at 21:19
You have a relatively large 4WD towing a relatively small caravan compared to some of the outfits I see going down the highway.

Tyre grip, shockers etc on the van - maybe, but still couldn't overlook the obvious and that is weight distribution to far back in the van and the resulting light ball weight.

With normal loads/water tanks etc it would be interesting to see what the tow ball weight is measured at before chasing other causes.

Good luck chasing it up.

(And G'day, haven't been round for a while :-)

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FollowupID: 785114

Reply By: The Bantam - Saturday, Mar 30, 2013 at 00:46

Saturday, Mar 30, 2013 at 00:46
We have to face facts that most caravans are fundamentally unstable.

The transport industry call a rigid trailer with a single axle group a "PIG" for very good reason. In heavy transport the PIG trailer is the cheap choice...look around how many highway trucks do you see towing pig trailers.

If everything is not right there will be problems.

195/14 light trucks are a fine and beaut load carrying tyre and should be capable of carrying over 800Kg per tyre at 60 psi....that is more than the wheel bearings in many trailers with 14 inch wheels are rated for.
There are thousands of overloaded work utes dragging there asses arround on them every day..its the standard tyre on 2wd hiluxes and most other 2wd utes.

As for traction issues with the trailer tyres.....Oh please if you have side shift problems and ya running out of traction on ya trailer tyres you are in seruious trouble.
Besides, the better light truck tyres handle & grip every bit as well and a decent passenger car tyre these days....if you doubt that get ya self on to some Michilin agilis, or the Maxis light trucks.

As for the springs on the caravan.....yeh ya may have a small problem there.

But the #1 cause of sway on trailers towed behind passenger cars is the rear of the tow vehicle moving arround.

If the suspension on the tow vehicle is soft and baggy....as the standard suspension is on any station waggon 4wd ( soft suspension makes em work off road) and there is no device to counteract this.....there is ya cause of trailer sway.

It will be even worse if the tow vehicle is nose up and ass down with ball weight.

If the tow vehicle is moving around on the road, the fundamentally unstable caravan, with the high centre of gravity will amplify that.

A weight distributing hitch will some shift the weight forward in the two vehicle, which will tend to track straighter and and flatter......there will be less movement for the pendulum that you are dragging around to amplify.

You can talk about all sorts of things that might hep a little bit.....but while the tow vehicle is moving around on the road, any pig trailer will sway, especially a long, heavy one with a high centre of gravity.

cheers
AnswerID: 507838

Reply By: Kiwi100 - Saturday, Mar 30, 2013 at 11:00

Saturday, Mar 30, 2013 at 11:00
LR won't approve WDHs on its self-levelling vehicles and owners often erroneously claim that therefore a WDH is "not needed". There's a difference between 'needed' and 'allowed'.

The self-levelling suspension will make it look OK but there's nothing it can do to return the weight to the tug's front wheels that has been lifted from them by your towball weight. Luckily, the LR has a relatively short distance between towball and the tug's rear axle but the van will still be levering weight off the tug's front wheels, reducing grip and therefore stability.

Get the rig into a weighbridge, drive the tug off the platform and find out what the van weighs while hitched. Then drop the jockey wheel onto the platform and disconnect the hitch. The difference will be your ball weight and should be around 10% of the van's solo weight. If it is less, therein might lie your problem.

Hitch up and reverse until only your tug's front wheels are on the platform and check the weight. Then unhitch again and you'll find out what weight is being removed from your front wheels by the weight the van places on the back of your tug.

Note all the figures and come back here with them. You don't need an official ticket so you might get away with no charge for the exercise. So long as the unhitched vehicles aren't moved, the exercise will be quick and easy. No need to disconnect electricals or chains and the hitch remains aligned.

But still get the hell out of there before those impatient truckies sort you out for holding them up. ;)

Michael
AnswerID: 507853

Reply By: ozjohn0 - Saturday, Mar 30, 2013 at 12:04

Saturday, Mar 30, 2013 at 12:04
The van should not be towed if it shows any sign of swaying.
Without getting to technical,
You'll first need to establish the fully laden weight of the van and it's Laden ball weight.
i.e. use a weighbridge.
The load should be distributed thoughout the van to give a ball weight for the old evernew of at least 10% of the vans fully laden weight.
50 PSI in the tyes is a good starting point and then test using the 4 - 6 PSI rule.
Best of luck, Ozjohn.
AnswerID: 507855

Reply By: Steve80 - Saturday, Mar 30, 2013 at 23:11

Saturday, Mar 30, 2013 at 23:11
Hi I had a 2001 td5 disco and was towing a 22ft 2t van. It was terrible at swaying. I've towed vans etc for well over 20 years and this was the worst combination I've come across. Not much worries me but I can tell you but I had quite a few anxious moments. I did everything weighed everything right down to separate axles weights, ball weight, how much weight the van took of the front car wheels. I went right into it and could not pick it. Van was packed appropriately. My van did sit slightly upwards on the tow vehicle so I lifted the height on the van to get level, although better, still not good. In the end I don't like not being able to use a wdh so I took the sls off and did a coil conversion with polyairs and changed my towbar to a HR one. It wasn't spot on but was a hell of a lot better manners on road and more tow friendly.

Cheers
AnswerID: 507894

Follow Up By: Kiwi100 - Monday, Apr 01, 2013 at 10:07

Monday, Apr 01, 2013 at 10:07
Good move, but I think I'd have still been aiming for 'spot on', Steve. Lifting the van might have been a little counter-productive by reducing the stability gains you had made elsewhere.

Caravan sway is a bit like smelling smoke in your house: act before it escalates into a disaster. A hint of sway under normal conditions indicates inherent instability and it takes very little to have that suddenly go wildly out of control. It happened in front of me a couple of years ago and it wasn't pretty - masses of damage, three vehicles caught up in it, but luckily nobody hurt.

Michael
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FollowupID: 785282

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