Fletch26:
Here’s the beast (click for full size and correct orientation). No counterweight■■?
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You said ‘‘much worse when loaded’’ ?.Depending on the weight of the pallets ( obviously heavy going by the need for 6 axles ) ? the problem is more likely to be the weight on the rear overhang of the prime mover ‘combined’,with more than enough nose weight of the trailer,lifting weight off the steer axle and just the pendulum effect of the moffet setting up the sway but the steer axle not having the weight on it to hold the outfit in line.IE tail wagging the dog at the front.Rather than a tail heavy trailer lifting weight off the prime mover drive/rear axles.You ain’t going to fix that by adding more nose weight to the trailer.More likely make it worse if not also take more load off the rear trailer axle and overload the prime mover’s drive/rear axles.
If so it’s a classic case showing the superiority of the A frame design on which you can chuck as much weight as you like on the prime mover up to it’s max gross and then couple it up to any trailer you like and more or less regardless of the trailer’s gross weight and weight distribution,if you wanted to and if they’d allow it.
While as so often it’s the unsupported load deck length,between the trailer’s 1st axle and the prime mover’s tag,which is probably literally the achilles heel in this case.It would at least be a start to get some axle weights just as it’s loaded there and check the steer axle and trailer’s rear axle weights.My guess is they’ll be light.While you could then also check if it’s the opposite situation of a tail heavy trailer lifting weight off the prime mover’s drive/tag and putting on the trailer’s rear axle in which case the tail will wag the dog at the rear of the prime mover not the front.
Punchy Dan:
Carryfast:
Punchy Dan:
You need a sheet of steel on the headboard to balance the trailer ,it helps to have a front lift and the axles set back rather than central to reduce the amount of weight needed on the headboard .
Assuming the steel is just ballast that’s more subtracted from the available payload and where is he going to find this heavy piece of steel plate.In addition to the fact that it requires an actual nose heavy positive load on the coupling for stability which then also has to be subtracted from the prime mover’s rear axle payload weight.While road surface undulations can still then set up a continuous rocking front to rear weight transfer from the trailer see sawing across it’s silly axle configuration,resulting in the prime mover then still going light on the drive axle and then going light on the steer.Which creates a continuing both types of tail wagging the dog effect from the rear of the prime mover and then at the front.Or possibly even both at once in the situation which the OP described of a possibly heavy,let alone tail heavy,trailer combinded with a downgrade.
All that aggro just to avoid applying the driving skills which previous generations here took for granted and which are still taught and taken as routine in most other parts of the world where a trailer is coupled to a rigid at least.In which the choice,between the advantages of the A frame configuration,compared to the flaws in the oversized caravan design,is rightly considered a no brainer and which really should be subject to legislation regarding any outfit of more than around 11 tonnes gross IE a 7.5 tonner pulling a 3.5 t gross trailer.
In the real world you will find that a sheet of steel on the headboard to add weight is the done thing ,you may not know this as you probably can’t google it and it’s not on caravan forums 
Really and exactly which caravan forums are extolling the virtues of A frame caravans.Over the even more lethal idea of zb close coupled 44t truck drawbar outfits because supposed C + E drivers have been scared into thinking that they can’t reverse a proper trailer ?.
As for the steel ballast on nose of the trailer.Assuming an already loaded to the max prime mover and trailer and bearing in mind the fact that you don’t even know whether the problem is too much nose weight on the trailer or not enough what could possibly go wrong.Even if he can find a two tonne piece of flat metal plate lying around the yard.
dave docwra:
I would suggest running with the tag axle in the up position at all times if possible.
Yeah like that’s going to work with a fully freighted 3 axle prime mover and the trailer nose weight adding to the drive axle weight.
Let alone if the problem is actually caused by the combined weight on the front overhang of the trailer and the rear over hang of the prime mover lifting weight off the steer axle. 
ukjamesuk:
Surely if you run with the tag down you get better lateral stability and less sway ? Lifting the tag gives better traction but that’s not the issue.
Two axles hold the rear in line better than one.But none of it is much help if they are either being lifted off the road by a tail heavy trailer.Or if a heavy on the nose trailer combined with a heavy on the rear prime mover lifts weight off the steer axle. 
That’s why the A frame configuration is still alive and kicking in places where they know better and they actually allow and teach drivers to drive ( reverse ).
As said in a few replies the Moffett will be making it a lot more unstable, they are bad enough on an artic when they are empty. Ours have a weighted steel plate on the headboard to counter it.
Punchy Dan:
Night-and-day:
As said in a few replies the Moffett will be making it a lot more unstable, they are bad enough on an artic when they are empty. Ours have a weighted steel plate on the headboard to counter it.
Don’t let real world use and ideas puncture Carryfasts fantasy now will you 
To be fair to carryfast (I know 
), he has a point, but then goes on and on on a tangent, burying his own argument… 
I’ve driven a-frame trailers, in fact I passed my test in the Netherlands in a full sized Scania combination. The ride and road holding are far, far superior over a drawbar trailer, never mind an artic.
Reversing an a-frame takes skill, but nothing that a bit of tuition and practice can’t solve.
Carryfast’s problem is that he needs to go full militant, going from “the a-frame trailer is better” (which it is) to “drawbars are bad and you must insist that your boss buys a new combination therefor”, and then proceeds to engage in combat with anybody who does not agree with him.
I wager he was a Shop Steward on the busses in the 70’s 
Been quite a while since I pulled a drag, but the thing that leapt out of the screen at me from the OP was the moffett hanging off the back.
This is a pretty old demonstration of weight distribution, but non the less valid for it.
dave docwra:
I would suggest running with the tag axle in the up position at all times if possible.
Would make it worse you want the coupling as close to the rear axle as possible. That’s why an artic is so stable because the coupling is ahead of the midpoint of the rear axle.
Artics with moffets on or loaded excessively are problematic but don’t tend to get into a snake as such the lack of load on the kingpin means when you brake even more load comes off the drive axle as the truck dips on the front that particularly in the wet a jack knife is easy to get into.
switchlogic:
Punchy Dan:
Night-and-day:
As said in a few replies the Moffett will be making it a lot more unstable, they are bad enough on an artic when they are empty. Ours have a weighted steel plate on the headboard to counter it.
Don’t let real world use and ideas puncture Carryfasts fantasy now will you
The ‘fact’ that I drove a similar,but even worse,4 axle type of outfit around 2,000 miles per week continuously for around 5 years.Which as I said had already destroyed another driver’s career through the type of severe accident which can all too predictably result when the close coupled trailer idea goes horribly wrong.
Also the ‘fact’ that having previously long before driven the family caravan all over the country ( because I had the type of car which could tow it,as opposed to my Dad’s 4 cylinder and lighter heap at the time 
),before I’d ever even driven a 7.5 tonner,was a great help later in teaching me how to load and handle the POS.Then did another 3 years continuous driving a 5 axle A frame outfit over the same type of distances,having already understood the latter’s inherent superiority ,is all fact not fantasy.Now awaits you going to trump all that with you did the same in addition to driving a bleedin bus in your spare time.
the nodding donkey:
To be fair to carryfast (I know ), he has a point, but then goes on and on on a tangent, burying his own argument…
I’ve driven a-frame trailers, in fact I passed my test in the Netherlands in a full sized Scania combination. The ride and road holding are far, far superior over a drawbar trailer, never mind an artic.
Reversing an a-frame takes skill, but nothing that a bit of tuition and practice can’t solve.
Carryfast’s problem is that he needs to go full militant, going from “the a-frame trailer is better” (which it is) to “drawbars are bad and you must insist that your boss buys a new combination therefor”, and then proceeds to engage in combat with anybody who does not agree with him.
I wager he was a Shop Steward on the busses in the 70’s
Let’s get this right we’ve got a considerable threat to road safety in the form of these POS close coupled type contraptions and you say let’s not get militant in doing something about it.By asking operators to review their buying criterea and if that doesn’t work the powers that be to legislate them off the road.
While since when were close coupled and A frame configurations not both types of drawbar outfits. 
It’s behaved itself today. Actually quite fun to drive.
It’s behaved itself today. Actually quite fun to drive.
Fletch26:
It’s behaved itself today. Actually quite fun to drive.
Can you identify anything different from last time when it misbehaved such as a more lightly loaded trailer for example or more weight on the front of the prime mover or the trailer etc etc ?.Or took the advice to apply a light hand in steering inputs ?.
Sorry it’s taken a while to reply, I wanted to give it the week to see for definite what I had done differently. It would seem that just having more confidence behind the wheel has helped, coupled with smoother inputs. Unfortunately, not had the manitou on the back this week apart from Monday so couldn’t really test my theory, although it was a lot better Monday. Seem to be running straw bales mostly at the moment. Takes a bit of getting used to with the truck leaning so much in every corner regardless of speed. Enjoying it though for the most part.
Fletch26:
Enjoying it though for the most part.
That’s what I’d always thought that I’d think about A frames after growing up surrounded by them during long Continental holidays and when I was finally lucky enough to get onto them here they didn’t disappoint.Unlike others’ observations I predictably found them far nicer to drive than close coupled outfits.But also artics and give the brain cells a bit of a welcome workout when reversing.
While it sounds like the moffet on the back is upsetting the trailer’s stability.Which in part is also not helped,if not caused,by its axles being in the middle not at each end of it.Resulting in any or all of the issues of just the pendlum effect of that and/or zero nose weight.Or even a negative nose weight actually lifting weight off the drive/rear axles of the prime mover.
While trying to cancel out too much,too far back,on the rear overhang of the trailer,by putting a load of ballast on the front one,is open to question.Or even viable regarding the resulting weight transfer and gross weight and axle weight limitations across the outfit.While also then possibly changing the problem from a lateral pendulum swaying effect to also more of a continous vertical see sawing one transferring to the prime mover.
On that note don’t ever get complacent about the potential for the things to go wrong in a big way quickly with the comment that down grades made things worse being a bit of a red flag in that regard.
That’s what I’d always thought that I’d think about A frames after growing up surrounded by them
I can concur with that having spent several years driving them. I loved A frames and the challenge initially of being able to control them whilst reversing. It took plenty practice but I cracked it eventually. I also loved the fact of lot of big headed artic drivers jumped in for the first time swearing it would be no problem and proceding to make a complete hash of it.
