newmercman:
Harry Monk:
Just a quick update, I phoned my (ex) boss and he said “Well, isn’t it obvious that if the drive axle is forward of the pin rather than behind it, that the truck will need more room to turn?”
I felt a bit of an idiot for asking, but as I said to him, I was only passing on questions.
Basically, eu turning circle legislation is what killed off tag-axle tractor units.
As I said in the first place 
Blimey it’s picking on Harry week for me
I think your man is wrong H? A tag usually has a 3.1m or 3.4m wheelbase, whereas a midlift has a 3.8m or 4.1m wheelbase, in this case wheelbase is measured from the center of the front axle to the center of the drive axle, so even though your 5th wheel is behind the drive axle it will be the same approximate distance from the center of the front axle in both configurations, or it should be if the pin setting on the trailer is correct and you don’t have to have the 5th wheel back to avoid fouling the underside of the trailer or hitting the legs/ripping the lights off
I’m trying to work it out in my head, but it’s all a bit fuzzy, I’m thinking that if the 5th wheel is behind the drive axle it should turn tighter, as you turn the unit the overhang effectively pulls the trailer out in a wider arc in much the same way as the overhang on an A frame wagon and drag does, those turn real tight with hardly any cut in, even in Crazyfast’s favourite rigid/13.6m trailer guise,
But I’m sane enough to know that the overhang on a rigid with an A frame actually steers the front bogie/dolly of a drawbar/composite trailer in the opposite direction to the turn to start with because of the two points of articulation and a fith wheel artic coupling just can’t do that. 
Which,together with some other benefits of the A frame principle,is why there’s just no way that an artic can match a drawbar outfit for turning even if the type of overhang,of a typical type rigid prime mover,with it’s lifting tag axle down,and a tag axle unit with or even without it’s tag down were comparable, which they’re not anyway.But surely there would’nt be any point to the turning test unless it has to be passed with all axles on the road and in use. 
Harry Monk:
Carryfast:
But there was another way (6x4) before we let the lunatics take over the asylum. 
Tin hat on. 
viewtopic.php?f=35&t=41082
Yep, 6x4s are very common in South Africa but they are allowed more weight there (MGW is 53 tonnes iirc), the roads are sometimes poor and fuel is cheaper. The disadvantages of 6x4 are the increased tare weight and that they use more fuel due to friction loss, for no real benefit at the weights we run.
Don’t encourage him Harry, he’ll be telling us the Africans have got it wrong now
Carryfast:
But the way that they’d see it is that the Brits are as mad to accept £5 per gallon for diesel as we are for using zb lifting axles that should be used for driving the thing along the road. .
Yes, from a mechanical perspective I completely agree with you.
From a humanitarian perspective I think trailers should be six feet shorter, and tractor units six feet longer so they could be fitted with a toilet and a shower like a motorhome is.
Neither will happen because the world is not run by mechanics or humanitarians, but by economists.
Harry Monk:
Carryfast:
But the way that they’d see it is that the Brits are as mad to accept £5 per gallon for diesel as we are for using zb lifting axles that should be used for driving the thing along the road. .
Yes, from a mechanical perspective I completely agree with you.
From a humanitarian perspective I think trailers should be six feet shorter, and tractor units six feet longer so they could be fitted with a toilet and a shower like a motorhome is.
Neither will happen because the world is not run by mechanics or humanitarians, but by economists.
Just put a 45 foot drawbar trailer on the back of this,with the aerodyne cab,and you’d probably have the best of all worlds enough to satisfy the mechanics,economists and the humanitarians.
hankstruckpictures.com/pix/t … railer.jpg
Carryfast:
Just put a 45 foot drawbar trailer on the back of this,with the aerodyne cab,and you’d probably have the best of all worlds enough to satisfy the mechanics,economists and the humanitarians.
hankstruckpictures.com/pix/t … railer.jpg
Yes, but the problem I can see is that the road network isn’t suited to it. It could possibly work running between motorway-connected depots but that’s about it. They are more suited to larger countries with long stretches of open road.
In any event, why would any small haulier or driver want them? All they would do would be to drive rates downwards, same as every increase in capacity has done.
Harry Monk:
Carryfast:
Just put a 45 foot drawbar trailer on the back of this,with the aerodyne cab,and you’d probably have the best of all worlds enough to satisfy the mechanics,economists and the humanitarians.
hankstruckpictures.com/pix/t … railer.jpg
Yes, but the problem I can see is that the road network isn’t suited to it. It could possibly work running between motorway-connected depots but that’s about it. They are more suited to larger countries with long stretches of open road.
In any event, why would any small haulier or driver want them? All they would do would be to drive rates downwards, same as every increase in capacity has done.
[/quote]
OMG, now you’ve done it, prepare yourself Harry
newmercman:
Harry Monk:
Carryfast:
Just put a 45 foot drawbar trailer on the back of this,with the aerodyne cab,and you’d probably have the best of all worlds enough to satisfy the mechanics,economists and the humanitarians.
hankstruckpictures.com/pix/t … railer.jpg
Yes, but the problem I can see is that the road network isn’t suited to it. It could possibly work running between motorway-connected depots but that’s about it. They are more suited to larger countries with long stretches of open road.
In any event, why would any small haulier or driver want them? All they would do would be to drive rates downwards, same as every increase in capacity has done.
OMG, now you’ve done it, prepare yourself Harry
[/quote]
Carryfast likes sausages 
Wheel Nut:
newmercman:
Harry Monk:
Carryfast:
Just put a 45 foot drawbar trailer on the back of this,with the aerodyne cab,and you’d probably have the best of all worlds enough to satisfy the mechanics,economists and the humanitarians.
hankstruckpictures.com/pix/t … railer.jpg
Yes, but the problem I can see is that the road network isn’t suited to it. It could possibly work running between motorway-connected depots but that’s about it. They are more suited to larger countries with long stretches of open road.
In any event, why would any small haulier or driver want them? All they would do would be to drive rates downwards, same as every increase in capacity has done.
OMG, now you’ve done it, prepare yourself Harry
Carryfast likes sausages
[/quote]
That explains a lot Malc, not allowed scissors you see although I did hear it was chipolatas not full size sausages
BTW did you know that the scissor was invented by Leonardo Da Vinci 
You’d have thought with all his brains and foresight he would’ve sorted it so that standpipe down the road from his place had hot water
Harry Monk:
Carryfast:
Just put a 45 foot drawbar trailer on the back of this,with the aerodyne cab,and you’d probably have the best of all worlds enough to satisfy the mechanics,economists and the humanitarians.
hankstruckpictures.com/pix/t … railer.jpg
Yes, but the problem I can see is that the road network isn’t suited to it. It could possibly work running between motorway-connected depots but that’s about it. They are more suited to larger countries with long stretches of open road.
In any event, why would any small haulier or driver want them? All they would do would be to drive rates downwards, same as every increase in capacity has done.
As Einstein said everything is relative.In real terms profitability would have gone up in line with capacity/efficiency not down.The problem is that costs and fuel taxation have increased faster and at a far larger rate than the artificially limited efficiency levels have been allowed to and we’ve now got a suicidal economic policy which let’s east european operators compete with west european ones.The relevant comparison would be a 65 tonner now,running under the same fuel and other costs (in real terms in line with inflation not political taxation increases) as when we used 32 tonners,in an economic environment without the east european competition which distorts all economic comparisons because of the head on crash which took place when the two types of economies were stupidly thrown together.But as we’ve been discussing elsewhere on here,with drivers who actually are driving those types of drawbar outfits,they are as easy,if not easier,to handle as the current spec artic outfits including in urban environments.It’s always been a case of more payload on the truck means more revenue not less.But profitability is another matter in the present climate.But you won’t increase profitability by reducing efficiency or every operator would be downplating their 40 and 44 tonners to 32 tonnes.
Turning Circle
Articulated vehicles with an overall length exceeding 15.5 metres; articulated vehicles with an overall length of 15.5 metres or less where both the tractor and semi-trailer were first used after 31 May 1998 and all goods vehicles defined as heavy motor cars first used after 31 May 1998 must be able to turn within concentric circles with radii of 12.5 metres and 5.3 metres.
A concession is allowed for car transporters so that any protrusion of the forepeak (for instance any part of the trailer forward of the kingpin) will be ignored.
The following vehicles are exempt;
1.any vehicle with an overall length not over 15.5 metres and first used before 31 May 1998
2.an articulated vehicle, the semi-trailer of which was manufactured before 1 April 1990 (and which has not been modified to increase its length since then)
3.a low loader - defined as a semi-trailer normally used to carry engineering equipment and constructed so that the major part of the load platform does not extend over or between the wheels and the upper surface is below the top of the tyres
4.a vehicle constructed and normally used for exceptionally long indivisible loads
5.a stepframe low loader - defined as a semi-trailer (not a low loader) constructed and normally used for engineering equipment and constructed so that the upper surface of the major part of the load platform is less than one metre above the ground
6.a vehicle having four or more axles where the distance between the foremost and rearmost axles exceeds 6.4 metres
Vehicles first used from 1 June 1998 which are fitted with a lift axle must now meet the turning circle requirements both with and without all the wheels in contact with the ground.
An articulated vehicle is deemed to meet the turning circle requirement if the distance from the kingpin (or front
kingpin) to the centre line of the non-steering bogie does not exceed 8.135 metres for a 2.55 metre wide vehicle.
courtesy Transportfriends
Wheel Nut:
newmercman:
OMG, now you’ve done it, prepare yourself Harry
Carryfast likes sausages
Yes, you see the point is, if you worked in a sausage factory, blah blah blah
Driveroneuk:
Vehicles first used from 1 June 1998 which are fitted with a lift axle must now meet the turning circle requirements both with and without all the wheels in contact with the ground.
An articulated vehicle is deemed to meet the turning circle requirement if the distance from the kingpin (or front kingpin) to the centre line of the non-steering bogie does not exceed 8.135 metres for a 2.55 metre wide vehicle.
Thanks, that answers that question, so Harry was correct with his 1998 thing, but would it make a difference if the axle was up or down? The point of articulation is still in the same place.
newmercman:
Wheel Nut:
newmercman:
Harry Monk:
Carryfast:
Just put a 45 foot drawbar trailer on the back of this,with the aerodyne cab,and you’d probably have the best of all worlds enough to satisfy the mechanics,economists and the humanitarians.
hankstruckpictures.com/pix/t … railer.jpg
Yes, but the problem I can see is that the road network isn’t suited to it. It could possibly work running between motorway-connected depots but that’s about it. They are more suited to larger countries with long stretches of open road.
In any event, why would any small haulier or driver want them? All they would do would be to drive rates downwards, same as every increase in capacity has done.
OMG, now you’ve done it, prepare yourself Harry
Carryfast likes sausages
That explains a lot Malc, not allowed scissors you see although I did hear it was chipolatas not full size sausages
BTW did you know that the scissor was invented by Leonardo Da Vinci You’d have thought with all his brains and foresight he would’ve sorted it so that standpipe down the road from his place had hot water
[/quote]
Leonardo Da Vinci also invented the helicopter but no one ever saw one built to his design actually zb fly .But if he’d have designed a truck instead you can bet that it would have been a euro spec 6x2 artic.
newmercman:
Didn’t want to steal your thunder Malc…Honest
The common denominator here is Phillips I once saw a DeRooy outfit, a 2500 Daf wagon and drag chassis, but it had a one piece body that IIRC was over 50’ long, the body was mounted on two 5th wheels, the one on the prime mover fixed, the one on the trailer a sliding affair, that thing had 20’ bits of chassis poking out when it turned and it also had the back of the cab shaved and a piece of ply as a rear wall that started at the back of the doors, with the big old flat steering wheel in those Dafs I would not even be able to get in the cab 
I remember that bloody monstrosity, the chassis would go round the roundabouts while the body collected all the street furniture
I gather it turned up in Dover and the man from the ministry met it and immediately sent it back from whence it came 
Driveroneuk:
Turning Circle
Articulated vehicles with an overall length exceeding 15.5 metres; articulated vehicles with an overall length of 15.5 metres or less where both the tractor and semi-trailer were first used after 31 May 1998 and all goods vehicles defined as heavy motor cars first used after 31 May 1998 must be able to turn within concentric circles with radii of 12.5 metres and 5.3 metres.
A concession is allowed for car transporters so that any protrusion of the forepeak (for instance any part of the trailer forward of the kingpin) will be ignored.
The following vehicles are exempt;
1.any vehicle with an overall length not over 15.5 metres and first used before 31 May 1998
2.an articulated vehicle, the semi-trailer of which was manufactured before 1 April 1990 (and which has not been modified to increase its length since then)
3.a low loader - defined as a semi-trailer normally used to carry engineering equipment and constructed so that the major part of the load platform does not extend over or between the wheels and the upper surface is below the top of the tyres
4.a vehicle constructed and normally used for exceptionally long indivisible loads
5.a stepframe low loader - defined as a semi-trailer (not a low loader) constructed and normally used for engineering equipment and constructed so that the upper surface of the major part of the load platform is less than one metre above the ground
6.a vehicle having four or more axles where the distance between the foremost and rearmost axles exceeds 6.4 metres
Vehicles first used from 1 June 1998 which are fitted with a lift axle must now meet the turning circle requirements both with and without all the wheels in contact with the ground.
An articulated vehicle is deemed to meet the turning circle requirement if the distance from the kingpin (or front
kingpin) to the centre line of the non-steering bogie does not exceed 8.135 metres for a 2.55 metre wide vehicle.
courtesy Transportfriends
That’s why Leonardo Da Vinci’s modern day lot are trying to build a semi trailer where the overhangs are almost as long as the overall length of the artic outfit.
For me the biggest problem with mid lift, most of which are non-steering is that the front pair turn, the back pair on a differential follow the line, but the two in the middle want to go on the way they were pointed, low speed entry into Silvey’s yesterday and the front wanted to go towards the kerb. If all lift axles were made steering axles, with the weight penalty which is imposed, that would be my preference.
newmercman:
Driveroneuk:
An articulated vehicle is deemed to meet the turning circle requirement if the distance from the kingpin (or front kingpin) to the centre line of the non-steering bogie does not exceed 8.135 metres for a 2.55 metre wide vehicle.
Thanks, that answers that question, so Harry was correct with his 1998 thing, but would it make a difference if the axle was up or down? The point of articulation is still in the same place.
Just as it would be if we coupled a 45 foot trailer onto a 6x4 yank conventional tractor unit.
bigdennis:
For me the biggest problem with mid lift, most of which are non-steering is that the front pair turn, the back pair on a differential follow the line, but the two in the middle want to go on the way they were pointed, low speed entry into Silvey’s yesterday and the front wanted to go towards the kerb. If all lift axles were made steering axles, with the weight penalty which is imposed, that would be my preference.
Silvey’s, that’s the one at J17 on the M4? If so, that place is lethal, I’ve had understeer there in a 4x2 with super singles on the front, there was a car coming up so I shot across lively and nearly ended up in the cafe, more to do with bad road surface than axle configuration (or in my case, speed )
But you’re right about handling, a positively steered mid lift will corner like it’s on rails
Crazyfast, a 6x4 yank with any trailer would be undriveable in the UK, trust me, I know about these things, you may get away with it in a swb Volvo, but a ‘proper’ yank tank would not be any fun at all
Driveroneuk:
Vehicles first used from 1 June 1998 which are fitted with a lift axle must now meet the turning circle requirements both with and without all the wheels in contact with the ground.
Yes. Like I said in the first place.
