Thread: Weight Question

Originally Posted by cripesamighty

If you get really bored Dave, a few AULROians were trying to explain that modern air-sprung Land Rovers don’t need WDH’s on a Caravaners forum thread. The Landy owners were pushing it uphill because those forum guys just cant comprehend it. Hilarious!

WDH with Air Suspension - "Please Explain!!!!" - Caravaners Forum - Since 2000

I like WDH when its all set up properly...

I'd argue that they should be used when (ignoring semis) the tow vehicle has less than 1.5X mass of the trailer and high speeds are expected (lets say extended runs over 80 KPH) BUT.....

Landrovers policy is they should not be used as they put the handling dynamics outside of what the computer thinks they will be.

and unfortunately 80% of the ones I have seen havent been setup properly and have the potential to make things worse.

so..

my official what I generally tell people position is..

"if you need a distribution hitch then you're not doing it right"

Originally Posted by Blknight.aus

Thats very neatly done,

did by chance you ever do ships loading, that looks markedly similar to the diagram maths they use for long point - point loads.

Thanks Dave, I never did ship loading but it would be exactly the same engineering maths. I did it at Uni.

Originally Posted by Blknight.aus

I know some farmers and truck drivers that this guy is going to need to have some big long discussions with and tell them how to do their job safely. We've got road trains out here massing over 100T all up and at best maybe 16 of that is the prime mover, lets be really generous and say that the prime mover and the front trailer weigh about 1/3 of the total mass, the next 2 to 7 trailers (I'm including mine specials on closed roads) still hughely out weigh the mover and trailer.

12T tractor hauling 35+T worth of machinery trailer or a string of product bins, every other day.


The only credit I can give him is this...

if you look at his exact arguments and accept all of the situations he presents as being factual and the only examples available he is more or less close enough to correct. However we dont operate in his exceptionally limited range of exposure.

If I remember rightly, I think an MF135 weighs in at about two ton,,, we’d have up to three trailers on the back with three apple bins on each. We used to work on an average of just under 500kg per bin (??), not sure what the trailers would weigh in at though, they were single axle, and damn heavy to try and lift up if they fell off they’re stands.
Ive seen longer bin trains, but not towed more than three myself. Seen a few incidents with runaways down hills etc,, always scary to watch.

Extact of Dave's post

I know some farmers and truck drivers that this guy is going to need to have some big long discussions with and tell them how to do their job safely. We've got road trains out here massing over 100T all up and at best maybe 16 of that is the prime mover, lets be really generous and say that the prime mover and the front trailer weigh about 1/3 of the total mass, the next 2 to 7 trailers (I'm including mine specials on closed roads) still hughely out weigh the mover and trailer.

12T tractor hauling 35+T worth of machinery trailer or a string of product bins, every other day.


Question
So does this all mean that my long term hearsay understanding that subject to all other aspects being covered, a car could pull a directly connected trailer that weighed up to 1.5 times the weight of the car is a furphy? (and that my 3T D4 therefore can't legally tow my 3.5T tandem trailer (as an aside, I follow the European model and have a towball weight of about 7%/200 kilos, rather than the AU 10%/350 kilos)

Originally Posted by gavinwibrow

Question
So does this all mean that my long term hearsay understanding that subject to all other aspects being covered, a car could pull a directly connected trailer that weighed up to 1.5 times the weight of the car is a furphy? (and that my 3T D4 therefore can't legally tow my 3.5T tandem trailer (as an aside, I follow the European model and have a towball weight of about 7%/200 kilos, rather than the AU 10%/350 kilos)

I just work off the manufacturers tow rating.

Also, totally agree that 10% ball weight is too high.
I also load based on drop on the towball height measurement - about 1" max which is less than 270kg on the rear axle, so probably about 200kg on the ball.

Blkknight.

100t combinations? That’s cute
Our combinations are 2-4 trailers and 300t min.

Originally Posted by gavinwibrow

Extact of Dave's post

I know some farmers and truck drivers that this guy is going to need to have some big long discussions with and tell them how to do their job safely. We've got road trains out here massing over 100T all up and at best maybe 16 of that is the prime mover, lets be really generous and say that the prime mover and the front trailer weigh about 1/3 of the total mass, the next 2 to 7 trailers (I'm including mine specials on closed roads) still hughely out weigh the mover and trailer.

12T tractor hauling 35+T worth of machinery trailer or a string of product bins, every other day.


Question
So does this all mean that my long term hearsay understanding that subject to all other aspects being covered, a car could pull a directly connected trailer that weighed up to 1.5 times the weight of the car is a furphy? (and that my 3T D4 therefore can't legally tow my 3.5T tandem trailer (as an aside, I follow the European model and have a towball weight of about 7%/200 kilos, rather than the AU 10%/350 kilos)

nope. roughly (and its old school) for cars and body trucks.

2/3of the vehicle weight for unbraked trailers
= weight for override olnly
1.5x vehicle weight with a command brake trailer

Originally Posted by Tombie

Blkknight.

100t combinations? That’s cute
Our combinations are 2-4 trailers and 300t min.

yep over 100T all up

I've personally only steered as high as 105T so thought it best for the purpose of the post to limit the info to my personal experience in the same vein as the other forums primary antagonist