Trailer Stabilty

[Guest]

It could - but it doesn't need to under Aussie rules as the caravan stays attached to the tow vehicle.

Then the reason for an electrical supply from the trailer to brake it for a minimum of 15secs, seems rather strange when a simple permanent brake from handbrake mechanism would suffice, unless of course a handbrake is not required in Australia.

[Stevan]

Back to stability, by far and away the most stable trailer arrangement so far has been the turntable drawbar type. It puts a negligible force on the tow car and is a lot easier to maneuver once you are used to it.

 

It would be interesting to see where that conclusion comes from! II have seen some pretty awful wobbles from that kind of trailer.

[Guest]

Back to stability, by far and away the most stable trailer arrangement so far has been the turntable drawbar type. It puts a negligible force on the tow car and is a lot easier to maneuver once you are used to it.

 

The most stable form of trailer is that of an "A" bracket towing a car, with the front suspension reset for towing rather than FWD or RWD, the problem for a van is that it causes chassis problems to accommodate the steered wheels as does the turntable type but to a greater extent due to the wheel position moving forward and rear on opposite sides.

[CommanderDave]

The most stable form of trailer is that of an "A" bracket towing a car, with the front suspension reset for towing rather than FWD or RWD, the problem for a van is that it causes chassis problems to accommodate the steered wheels as does the turntable type but to a greater extent due to the wheel position moving forward and rear on opposite sides.

 

 

I think I remember reading somewhere trailers with 4 wheel and a turntable steering are illegal in France for that reason as they can easily roll when the turntable steering is turned ?

 

 

 

 

Dave

[Guest]

I think I remember reading somewhere trailers with 4 wheel and a turntable steering are illegal in France for that reason as they can easily roll when the turntable steering is turned ?

 

 

 

 

Dave

Certainly the front track effectively narrows as the angle of turn increases leading to an almost Reliant Robin and instablility. Should it become detached it will almost certainly overturn as the turntable will naturally go to full lock

[CommanderDave]

Certainly the front track effectively narrows as the angle of turn increases leading to an almost Reliant Robin and instablility. Should it become detached it will almost certainly overturn as the turntable will naturally go to full lock

 

At least a reliant robin tapers and the engine is in the middle with a trailer it would mean any weight in the front corners is unsupported .

 

 

Dave

[Towtug]

I think I remember reading somewhere trailers with 4 wheel and a turntable steering are illegal in France for that reason as they can easily roll when the turntable steering is turned ?

 

 

 

 

Dave

 

A lot of truck trailers 03 and 04 use this principle with no problem.

The legality for 02 trailers is certainly an issue as you cannot Type approve them as they are not allowed over under brakes. In the UK you can use them but only if IVAd

[beejay]

Back in the '70s or early '80s, Lynton did produce a 4-wheeled caravan (one wheel at each corner) - I don't know if it used a turntable drawbar or ackerman steering like mobile artillery - production ended before Lynton went bust

 

 

In 1985 Lynton produced two prototypes. Never went into production being too heavy and too expensive.

 

Turntable drawbars are used for showmen's caravans and living vans. ...

[Black Grouse]

 

 

In 1985 Lynton produced two prototypes. Never went into production being too heavy and too expensive.

 

Turntable drawbars are used for showmen's caravans and living vans. ...

And are allowed to tow an extra trailer/caravan behind the showmans caravan

[CommanderDave]

And are allowed to tow an extra trailer/caravan behind the showmans caravan

If I remember they can tow a third to a outfit length of 25m but it has to be used in running the tow vehicle from aimed at the days when a trailer carried coal and water.

 

Engine - ride - living van - coal/water.

 

 

 

Dave

Edited December 14, 2015 by CommanderDave

[Black Grouse]

Showmen get quite specific long standing exemptions - they'll routinely use a heavy haulage tractor, often with a huge generator fitted, plus a 4-wheel turntable showmans caravan and a conventional single/twin axle caravan.

[Towtug]

I'm not actually sure if cars are precluded from towing more than one trailer, I believe it is allowed ( if only mby virtue of it not being specifically excluded) , indeed the DVSA say that if towing more than one trailer the number plate needs to go on the rearmost trailer. I personally wouldn't fancy it with a car.

 

Heavy locomotives are allowed up to 3 trailers depending on weight and overall train length restrictions.

 

Good luck parking that lot.

[CommanderDave]

I'm not actually sure if cars are precluded from towing more than one trailer, I believe it is allowed ( if only mby virtue of it not being specifically excluded) , indeed the DVSA say that if towing more than one trailer the number plate needs to go on the rearmost trailer. I personally wouldn't fancy it with a car.

Heavy locomotives are allowed up to 3 trailers depending on weight and overall train length restrictions.

Good luck parking that lot.

 

 

 

Interesting point . Overrun brakes could not be used but if independent braking system is used and a vehicles GTW is not exceeded and under 18 M outfit length should it be legal or not ?

 

 

 

Dave

[Towtug]

Interesting point . Overrun brakes could not be used but if independent braking system is used and a vehicles GTW is not exceeded and under 18 M outfit length should it be legal or not ?

 

 

 

Dave

I have a technical committee meeting next week I will ask if I have the opportunity

[Mr Plodd]

The ONLY class of vehicles that can legally tow more than one trailer are Agricultural vehicles (tractors) and there are all sorts of "only ifs", and "ands" to deal with (land implement conveyors and the such like) , and Showmans wagons (fairground) which must fit the definition of "Locomotive" as below from the Con & Use Regs

 

a mechanically propelled vehicle which is not constructed itself to carry a load other than the following articles, that is to say, water, fuel, accumulators and other equipment used for the purpose of propulsion, loose tools and loose equipment, and the weight of which unladen exceeds 7370 kg.

 

There is also an exemption for the seaside resort "Noddy train" type outfit for some bizarre reason.

 

The four wheel trailers with a rotating front axle are very common in France, market traders use them all the time BUT they have caused a huge number of fatalities because unless the drawing vehicle and trailer are directly behind each other when the towing vehicle brakes the turntable on the trailer can rotate out of line, the brakes can then no longer operate (because the braking ram is not being pushed straight back) and the trailer overturns when the turntable reaches the end of its rotation ability.

 

For THAT reason the new EU trailer regulations state that ONLY (new) 2 wheeled trailers can have over-run brakes.

 

Before anyone asks. ......Twin axle caravans have the axles close enough (points of contact with the road surface within one metre) to be LEGALLY classed as single axled.(The actual terminology used is "Close Coupled") Tag axle Motorhomes are the same.

 

To my view the current trailer braking systems do exactly what they need to. They are simple, they work, and the braking effort is regulated by the most simple of devices possible with next to nothing to go wrong, the tow hitch, the more the caravan attempts to over-run the towing vehicle the harder the caravan brakes are applied (and vice versa)

I am a great believer in "If it aint broke, dont fix it"

 

Andy

Edited December 15, 2015 by Mr Plodd

[CommanderDave]

I have heard of the US import 5th wheels towing jet ski trailers as they have a towing hitch as standard.

 

 

 

Dave

Edited December 15, 2015 by CommanderDave

[ddcman]

All caravans (except maybe very small ones) in Australia have electric brakes. The signal is analog (ie, the harder you brake, the greater the voltage applied to the brakes). It is a pendulum type thing, some versions are electronic, older ones are mechanical. The breakaway cable only operates if the chains somehow become disconnected from the tow vehicle. All vans with electric brakes must have a battery to operate the brakes if it comes adrift from the tow vehicle. All vans must have a hand brake as well. If a wobble occurrs, you can operate the van rakes to try and pull out of the wobble. Best advice is don't go to fast.

[Towtug]

All caravans (except maybe very small ones) in Australia have electric brakes. The signal is analog (ie, the harder you brake, the greater the voltage applied to the brakes). It is a pendulum type thing, some versions are electronic, older ones are mechanical. The breakaway cable only operates if the chains somehow become disconnected from the tow vehicle. All vans with electric brakes must have a battery to operate the brakes if it comes adrift from the tow vehicle. All vans must have a hand brake as well. If a wobble occurrs, you can operate the van rakes to try and pull out of the wobble. Best advice is don't go to fast.

You can get approval for this type of system within the EU also. There are a number of Centre axle and semi trailer manufacturers offering it on trailers up to 3500 kg.

[CommanderDave]

All caravans (except maybe very small ones) in Australia have electric brakes. The signal is analog (ie, the harder you brake, the greater the voltage applied to the brakes). It is a pendulum type thing, some versions are electronic, older ones are mechanical. The breakaway cable only operates if the chains somehow become disconnected from the tow vehicle. All vans with electric brakes must have a battery to operate the brakes if it comes adrift from the tow vehicle. All vans must have a hand brake as well. If a wobble occurrs, you can operate the van rakes to try and pull out of the wobble. Best advice is don't go to fast.

 

 

 

Not on boat trailers ? Salt Water and electric brakes are not a good mix and in the US they use surge brakes or over run as we call them.

 

 

Dave

[ddcman]

I don't know about boat trailers, never bothered to have a look. A large proportion of caravaners use a WDH of some description. Whether they are really required is debatable I reckon. I secretly think there is a bit of the Lemming principle involved with their use, ie he uses one, so I better too. I use to use one when I first got the van, but I think they put a lot of stress on the towbar connection, especially on undulateing dirt roads. The intructions say to not use them on dirt roads, but most do. Even going in and out of servos would be a problem, because there is quite a dip. There are always big differences of opinion on the local caravanersforum here, as to their use. Anytime someone posts a pic of a caravan accident, the first thing someone says is "did he have a wdh?". All the 'experts' examine it to the nth degree, quite entertaining sometimes!

I can't detect any difference in the feel with, or without the WDH fitted. Trick is not to go to fast. I've also heard the theory of accelerating out of a wobble, but, even if I thought it was a good idea, my rig just ain't gunna do it. Trying to pass big trucks seems to get some in s bit of bother. If I see one up ahead, I slow down and leave a big gap so that others can pass, or I pull over.

[Stevan]

What is a WDH? Is it what we call a hitch head stabiliser? Does sound a bit like our fuss over 85%!

[Black Grouse]

What is a WDH? Is it what we call a hitch head stabiliser? Does sound a bit like our fuss over 85%!

Weight distribution hitch - common in Australia and North America to permit a much higher trailer noseweight but spread that weight across both axles of the car.

 

http://auto. howstuffworks. com/auto-parts/towing/equipment/hitches/towing-weight-distribution-systems. htm

 

The Scott-Halley and Bulldog blade stabilisers were a form of WDH but a lot lower rated than the Austrailian/American types.

[Lutz]

Weight distribution hitch - common in Australia and North America to permit a much higher trailer noseweight but spread that weight across both axles of the car.

 

http://auto. howstuffworks. com/auto-parts/towing/equipment/hitches/towing-weight-distribution-systems. htm

 

The Scott-Halley and Bulldog blade stabilisers were a form of WDH but a lot lower rated than the Austrailian/American types.

 

Not much good with our relatively meagre noseweight limits, though.

[Black Grouse]

 

Not much good with our relatively meagre noseweight limits, though.

Some of the vehicles sold in Europe are also sold in Australia and North America with little or no structural differences and their importer/regulator permits WDHs to be fitted.

[JTQ]

Some of the vehicles sold in Europe are also sold in Australia and North America with little or no structural differences and their importer/regulator permits WDHs to be fitted.

The weight limit though can come from the caravan itself and here by and large we have 100 kgs limited chassis on mainstream vans.