Thread: Towing Caravans

Originally Posted by RonMcGr

This is from a Road Test with a Discovery 3, air suspension:
“Evident within the first few kilometres was a quiet, cushion-soft ride and steering that offers the usually conflicting qualities of light control and plenty of feel. Unfortunately, also evident was a nervous gait that had me dropping the nose of the van just six kays up the road. With the hitch dropped two holes, it still wagged during another dozen kilometres of freeway; I lifted the chains one link each side.

Whoa, it made a hell of a difference. No more wiggle. It seems the Disco - due, no doubt, to its auto-levelling suspension - is very sensitive to ride height and load-distributing chain tension. Sorted, 100kph cruising was a doddle and it was difficult not to creep up to 110 where the Disco diesel, in fact, felt happier.”

Ron, this is a very informative thread you've got here.

With respect to the above comment. Did these testers try towing without the WHD first? This statement would appear to indicate that they put the WDH on anyway. This would 'confuse' the vehicles systems.

Originally Posted by Jamo

Ron, this is a very informative thread you've got here.

With respect to the above comment. Did these testers try towing without the WHD first? This statement would appear to indicate that they put the WDH on anyway. This would 'confuse' the vehicles systems.

Jamo,

They put it on for safety reasons, as the did on every other vehicle tested. It did confuse the vehicles suspension and that is why they reset the chains twice, to get the ideal setting.

I gather, once they had the WDH set properly, the suspension stopped trying to re-adjust, and everything then went well.

Originally Posted by Brian Hjelm

Centre point of a turntable of a real semi-trailer rig is usually about 300mm ahead of the centre line of the rear axles, not on centre as in the photo above. On or behind centre pin gives noticeably worse ride and handing. Try it some time.

I have been told once, although not by someone in authority, that in Australia, 5th wheel caravans, horse floats, etc have the tow point slightly behind the rear axle for licencing reasons. Apparently if the pivot point is forwards of the rear axle, then you require a HC licence to drive the combination.

If the pin is on or behind centre then the lightly laden front axle will try to pivot up and down on bumps around the centre of the rear axle giving a bobbing ride motion and understeer. Pin ahead puts a load on the front axle. Pin on centre or behind is uncomfortable and pin behind is definitely dangerous. I have no idea if these gooseneck rigs need a HC licence to drive but they should. I also firmly believe that a car driver towing any trailer bigger than a light domestic rubbish dump trailer should have a special licence and have to undergo mandatory training. Maybe then truckies would not call caravanners terrorists in lieu of tourists.

There is a few Diagrams in this article on the point of articulation.
ROAD TRAFFIC (VEHICLE STANDARDS) RULES 1999 - REG 176

Ok folks interesting read but I have a question.

I tow a camper trailer that can weigh up to 1.2 tonne. The recommendation from the manufacturer of the camper trailer is not to use WDH's.

So with this in mind it is important to pack the camper properly with the weight as they suggest in their manuals.

However I still get some sag on my rear wheels especially when travelling long distances.

I was thinking of putting some polyairs in the back to remedy this situation but I have been told that, whilst they will level the vehicle - it is not as good as WDH's and makes little difference to the pivot point.

So now I'm stuck on what to do. I always assumed the self-levelling systems used a polyair type set up and a computer to level the suspension anyway, so what's the go? Have I been misled?

Are polyairs any good when compared to WDH's in this situation?

EDIT: I do not want to send this thread off-track, if you feel I should raise a new thread on this let me know and I will do so. I posted because I thought it relevant to the topic being discussed.

Originally Posted by Grizzly_Adams

Ok folks interesting read but I have a question.

I tow a camper trailer that can weigh up to 1.2 tonne. The recommendation from the manufacturer of the camper trailer is not to use WDH's.

So with this in mind it is important to pack the camper properly with the weight as they suggest in their manuals.

However I still get some sag on my rear wheels especially when travelling long distances.

I was thinking of putting some polyairs in the back to remedy this situation but I have been told that, whilst they will level the vehicle - it is not as good as WDH's and makes little difference to the pivot point.

So now I'm stuck on what to do. I always assumed the self-levelling systems used a polyair type set up and a computer to level the suspension anyway, so what's the go? Have I been misled?

Are polyairs any good when compared to WDH's in this situation?

EDIT: I do not want to send this thread off-track, if you feel I should raise a new thread on this let me know and I will do so. I posted because I thought it relevant to the topic being discussed.

Hi Glen,

I would probably go for a lighter WDH.
Not the heavy Hayman Reese, the smaller 4 bar one like I use. It lifts the back of the Disco a little and keeps everything in line :-)



These are rather cheap ($100, cheaper second hand) and work well with lighter loads.

Cheers

Originally Posted by Brian Hjelm

need a HC licence to drive but they should. I also firmly believe that a car driver towing any trailer bigger than a light domestic rubbish dump trailer should have a special licence and have to undergo mandatory training. .

I agree 100%.