trucken:
[quote
If you load it properly the weight imposed on the prime mover with a close coupled trailer will be minimal.
Computer controlled air suspension will keep it balanced.
Define load it properly assuming a load that that doesn’t have perfect weight distribution across the trailer.
Yes agreed according to Dave this air suspension is obviously miraculous stuff so go ahead load the prime mover to its max gross and the trailer air suspension will ensure zero hitch weight every time, not more or less regardless of what’s loaded on it and where.
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I’ve obviously been doing it wrong for the last 25 years!
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Around 25 years ago I’d luckily upgraded from driving Close Coupled to A frame drawbars and with it all of my previous close coupled trailer weight distribution and resulting prime mover axle weight worries evaporated to nothing.
I don’t remember any ‘computer controlled’ air suspension then which could fix variations from an overloaded front trailer axle and prime mover drive axle and light steer axle to a light drive axle and overloaded rear trailer axle from one night to the next.To the point of often ordering the reloading of the trailer and a previous driver losing his bottle to ever drive again after ending up on his side facing Southbound in the Northbound carriageway of the M6 because of a totally trailer heavy outfit.
Assuming that even exists now.
Basically close coupled outfits are a weight distribution liability no different to an oversized car and caravan outfit.
Strange how someone previously also pointed out the ‘hitch weight’ flaw but only I got flamed for daring to mention it.
trucken:
Trailer suspension design has changed somewhat in the last 25 years.
It can’t possibly ‘change’ the fact that a close coupled trailer is just a giant see saw with its centre placed axles being the pivot point.Any weight placed ahead of those axles transfers to the hitch and thereby rear/drive axle/s of the prime mover.
Any weight behind the trailer axles lifts weight off the hitch etc etc.
The things are obviously an even worse liability in the case of indivisible loads like plant which may not have perfect weight distribution front to rear.
The fact remains that weight transfer whether positive or negative, from trailer to prime mover via the hitch, is what defines combination weight v train weight.
trucken:
Trailer suspension design has changed somewhat in the last 25 years.
It can’t possibly ‘change’ the fact that a close coupled trailer is just a giant see saw with its centre placed axles being the pivot point.Any weight placed ahead of those axles transfers to the hitch and thereby rear/drive axle/s of the prime mover.
Any weight behind the trailer axles lifts weight off the hitch etc etc.
The things are obviously an even worse liability in the case of indivisible loads like plant which may not have perfect weight distribution front to rear.
The fact remains that weight transfer whether positive or negative, from trailer to prime mover via the hitch, is what defines combination weight v train weight.
See, you’re doing it again. You have something right (that a close coupled trailer imposes a weight onto the towing hitch), but bury it in so much waffle (some wrong, some unrelated), that people don’t take any of what you say serious.
I actually agree with you, that an A frame trailer is more stable, and forgiving when it comes to loading/weight distribution. I
I (and everybody else) disagree with your assertion that ANY close coupled trailer is by definition an unstable death trap.
And stop bring GCW Vs GTW into the discussion. They are the same thing.
trucken:
Trailer suspension design has changed somewhat in the last 25 years.
It can’t possibly ‘change’ the fact that a close coupled trailer is just a giant see saw with its centre placed axles being the pivot point.Any weight placed ahead of those axles transfers to the hitch and thereby rear/drive axle/s of the prime mover.
Any weight behind the trailer axles lifts weight off the hitch etc etc.
The things are obviously an even worse liability in the case of indivisible loads like plant which may not have perfect weight distribution front to rear.
The fact remains that weight transfer whether positive or negative, from trailer to prime mover via the hitch, is what defines combination weight v train weight.
See, you’re doing it again. You have something right (that a close coupled trailer imposes a weight onto the towing hitch), but bury it in so much waffle (some wrong, some unrelated), that people don’t take any of what you say serious.
I actually agree with you, that an A frame trailer is more stable, and forgiving when it comes to loading/weight distribution. I
I (and everybody else) disagree with your assertion that ANY close coupled trailer is by definition an unstable death trap.
And stop bring GCW Vs GTW into the discussion. They are the same thing.
An A frame trailer isn’t just ‘more forgiving’ it’s a totally different animal in that regard because it works on the principle of train weight.
You generally can’t load a close coupled outfit’s prime mover to its maximum gross weight because of the additional imposed hitch weight of the trailer which can be more or less depending on its weight distribution.
So the person who said weigh the prime mover and the trailer separately then add the result together to get the train weight and payload figures is only correct in the case of an A frame outfit.
That simply isn’t the correct way to do it in the case of a close coupled outfit.Because that works on the principle of combination weight/weights.In that what you put on the trailer and where, affects the hitch weight applied to the prime mover which especially affects it’s rear/drive axle weights.The only sure way to measure it is by weighing all of the axle weights in the loaded and coupled state.
Having said that experience and a good eye can suffice in being able to gauge a dodgy loaded close coupled outfit v a relatively good one.
A bad one you’ll also generally know within the first few miles at motorway speeds by feel through the steering.
Basically it’s a dangerously flawed way to run a heavy truck magnifying all the weight distribution and stability issues of a typical car and caravan outfit.All because employers want to avoid the need for the A frame reversing skillset.
Agree or disagree with that I don’t really care.
Butcha do you though. It’s why you type and copy off the net, pages of nonsense about A frames in a desperate effort to convince people you know what you’re talking about.
Am I missing something?
Are all close coupled outfits an Artic tractor unit and a trailer? i.e. the prime mover has load carrying capacity
Anything else is a wagon and drag?
Also, how do you get a trailer onto a weighbridge without it being connected to the prime mover?
stu675:
Am I missing something?
Are all close coupled outfits an Artic tractor unit and a trailer? i.e. the prime mover has load carrying capacity
Anything else is a wagon and drag?
Also, how do you get a trailer onto a weighbridge without it being connected to the prime mover?
A tractor unit by definition only bears the weight of a semi trailer.
In the case of an A frame outfit the prime mover and trailer are separate entities and weighed separately then the sum of both weights are added together to provide the gross train weight.The trailer will never impose any weight on the prime mover.
A close coupled outfit is weighed just like an artic in which the trailer weight and it’s distribution will affect the gross/axle weights of the unit.A close coupled trailer being even worse with its axles being set around the centre of the trailer which acts like a giant see saw in the way its weight and weight distribution affects the prime mover.In addition to the prime mover’s load weight.
The result being the gross combination weight which can only really be determined by measuring all the separate axles of the outfit when it’s loaded and coupled.Which will firstly show up any of the worst weight distribution issues in addition to overloading of the gross weight of the prime mover, by trailer weight transfer.
stu675:
Also, how do you get a trailer onto a weighbridge without it being connected to the prime mover?
^
Edit to add think about it.You just drop the trailer after dragging it onto a weighbridge.
Weigh it then re couple it and drive it off.
Same with the prime mover add the two resulting figures together bingo that’s the GTW.It’s obviously only relevant in the case of an A frame outfit.
Unlike the totally different measurement of GCW which by definition means weighing the prime mover and trailer together while coupled to take account of trailer weight transfer which could also even mean it lifting weight ‘from’ the prime mover’s drive/rear axles with a negative hitch weight which is an even more lethal situation than overloaded drive/rear axles.
stu675:
Also, how do you get a trailer onto a weighbridge without it being connected to the prime mover?
^
Edit to add think about it.You just drop the trailer after dragging it onto a weighbridge.
Weigh it then re couple it and drive it off.
Same with the prime mover add the two resulting figures together bingo that’s the GTW.It’s obviously only relevant in the case of an A frame outfit.
Unlike the totally different measurement of GCW which by definition means weighing the prime mover and trailer together while coupled to take account of trailer weight transfer which could also even mean it lifting weight ‘from’ the prime mover’s drive/rear axles with a negative hitch weight which is an even more lethal situation than overloaded drive/rear axles.
stu675:
Are all close coupled outfits an Artic tractor unit and a trailer? i.e. the prime mover has load carrying capacity
It is my understandng that “close coupled” refers to the distance between the back of the unit cab/rigid and the front of the trailer (1)(2), nothing to do with the trailer type or axles. Ie., for an arctic, there’s not enough space to get on the catwalk to connect the air lines so you need a sliding 5th wheel, mavis/ground access rail or to split couple. It is (apparently) also used to describe some drawbar trailers (here), they seem to have a sliding drawbar.
Edit:
All “axles in the middle”/seesaw drawbar trailers seem to be called close coupled (see here). TIL.
End edit.
stu675:
Anything else is a wagon and drag?
It is my understandng that it’s about the coupling, either articulated (5th wheel/unit and semi trailer) or drawbar (rigid = wagon and drawbar trailer = drag) (here). An “a-frame” is still a drawbar and a wagon and drag.
stu675:
Also, how do you get a trailer onto a weighbridge without it being connected to the prime mover?
Weigh the unit/rigid. Couple the trailer. Weigh the combination. Combination weight - Unit/Rigid weight = Trailer weight. (Works with an axle weigh"bridge", too.) I suppose if you had long enough access to a weighbridge you could uncouple the trailer on it.
Carryfast:
Which is why that’s the called the gross combination weight of a close coupled outfit.As opposed to the gross train weight of an A frame outfit where that calculation doesn’t apply.
stu675:
Are all close coupled outfits an Artic tractor unit and a trailer? i.e. the prime mover has load carrying capacity
It is my understandng that “close coupled” refers to the distance between the back of the unit cab/rigid and the front of the trailer (1)(2), nothing to do with the trailer type or axles. Ie., for an arctic, there’s not enough space to get on the catwalk to connect the air lines so you need a sliding 5th wheel, mavis/ground access rail or to split couple. It is (apparently) also used to describe some drawbar trailers (here), they seem to have a sliding drawbar.
Edit:
All “axles in the middle”/seesaw drawbar trailers seem to be called close coupled (see here). TIL.
End edit.
stu675:
Anything else is a wagon and drag?
It is my understandng that it’s about the coupling, either articulated (5th wheel/unit and semi trailer) or drawbar (rigid = wagon and drawbar trailer = drag) (here). An “a-frame” is still a drawbar and a wagon and drag.
stu675:
Also, how do you get a trailer onto a weighbridge without it being connected to the prime mover?
Weigh the unit/rigid. Couple the trailer. Weigh the combination. Combination weight - Unit/Rigid weight = Trailer weight. (Works with an axle weigh"bridge", too.) I suppose if you had long enough access to a weighbridge you could uncouple the trailer on it.
Carryfast:
Which is why that’s the called the gross combination weight of a close coupled outfit.As opposed to the gross train weight of an A frame outfit where that calculation doesn’t apply.
This “Arctic R” has a “Max Train Weight” of 44t.
I am happy to be corrected.
Edited many times.
Close coupled denotes the type of drawbar trailer which differentiates it from an A frame type.
Nothing to do with artics.Which is tractor/ive unit and semi trailer configuration.
The plate shown just proves that the white collar pen pushers at the DVSA haven’t got a clue when it comes to understanding the difference between gcw v gtw.
So how does a tractor unit get loaded to 24t running solo ?.
How can something that works on the principle of load transfer between the trailer and prime mover or tractor unit, be categorised in terms of a weight standard which applies to a configuration in which there is no such transfer ( just like train carriages ).
As opposed to gross combination weight which is by definition weighed on the basis of the combined axle weights to take account of the stated weight transfer issue.
So artics and close coupled drawbar outfits are gcw not gtw.
A frame drawbar outfits are gtw in which the prime mover and trailer are weighed separately in their own right and then the result is added together.
The DVSA are obviously creating the dangerous situation in which people apply the latter standard to the former ( wrong ) type.
I know these didn’t catch on and Foden calls it a twin load but is it an artic (has a fifth wheel) or wagon and drag ?
It’s just a short semi trailer which obviously imposes all of its pin weight on the prime mover in the similar way as an artic.So again it’s a ‘combination’ not a ‘train’ and therefore it will still affect the gross and axle weights of the prime mover.
Do I remember correctly from my teen years in Newark before the by pass was built.(early 1960s) ? F.and F.Robinson trucks parked at the cafe on Castlegate,their Fodens having similar configuration.
