60 tonne, 82' 10" road trains outside your local store

[Scuffers]

jayfrancis said:

Well I don't profess to know all the laws of physics.

But I know this. Whatever weight you have over your drive axle is going to be halved if you spread it over 2 drive axles. It's the weight that gives traction and if you halve it the wheels will spin even more. The non driving axle on single drive trucks can be lifted to increase weight on the drive axle hence more traction. There are some situations though when any truck will get stuck.

true enough to a point.

the point being that having an un-driven 3rd axle rather blows that argument out the window, as you now have a loaded axle taking weight from the driven one and needing to be pushed though the snow.

also, two tyres with half the weight on them have more grip than 1 with all the weight.

[handpaper]

Super Slo Mo said:

OP, you should write for the daily mail, with that sensationalist claptrap as your opening gambit.

The fact is, a single truck pulling two trailers is both shorter and lighter than 2 individual artics pulling the same load. They wouldn't get used on multi-drop deliveries (ie to your local convenience store, it's difficult enough for a standard artic as it is), but for inter-depot trunks, much like the double deck trailers do (which don't do store deliveries either).

Motorway congestion would reduce (which is a good thing, surely), haulage costs would drop somewhat too. There's be no difference in braking performance or road damage since the weight per axle wouldn't change.

I really don't see why the small minded have a problem with this. Fewer trucks, less cost to us the consumer, less congestion. What's not to like?

Actually, Tesco, Asda, Wilkinsons, Co-operative, B&Q and Pets at Home (and probably a good few more) all use double decker trailers for store deliveries. It's not a problem really - we just have to pay close attention to bridge heights

With regard to fuel economy, much of the effort in moving an artic at speed is expended in overcoming air resistance, so longer vehicles could offer significant savings, particularly over double-deckers.

[jayfrancis]

Scuffers said:

true enough to a point.

the point being that having an un-driven 3rd axle rather blows that argument out the window, as you now have a loaded axle taking weight from the driven one and needing to be pushed though the snow.

also, two tyres with half the weight on them have more grip than 1 with all the weight.

Read what I wrote again. The non driving third axle can be lifted off the ground. This can be done for various reasons. It can be for light or empty running, to avoid tyre scrub as they can be unsteered or in the instance we are debating to increase traction on the driven axle.

[Scuffers]

jayfrancis said:

Read what I wrote again. The non driving third axle can be lifted off the ground. This can be done for various reasons. It can be for light or empty running, to avoid tyre scrub as they can be unsteered or in the instance we are debating to increase traction on the driven axle.

at which point, the last sentence I posted covers it, like I said, you can't argue with the laws of physics.

[GC8]

jayfrancis said:

All very interesting. I was just making the point that single drive trucks are better than double drive trucks in those sort of conditions. Do you think a truck with double drive axles would fair any better in those conditions?

With diff locks and cross locks, yes: it certainly would. What you said may be perfectly correct when talking about driving exclusively on the road, but dual purpose vehicles (asphalt/aggregate tippers for example) do require dual drve and theyd be hobbled without it.

Posters suggesting that these over-weight combinations will be used for anything other than approved route trunking, deliveries to their local Tesco Mtro for example, are foolish.

The only issue that I can see, other than route closure; is that of recovery.

[jayfrancis]

Scuffers said:

at which point, the last sentence I posted covers it, like I said, you can't argue with the laws of physics.

I think you can. I just did and you agreed.

The more weight you can push down on one set of wheels the better it will grip. Fact.

Do you understand the difference between single and double drive?

[Nickyboy]

jayfrancis said:

I think you can. I just did and you agreed.

The more weight you can push down on one set of wheels the better it will grip. Fact.

Do you understand the difference between single and double drive?

There is a reason double drive is used in industries such as waste haulage, heavy haulage etc, its called traction. Twice the amount of driven wheels means twice the grip. You can have all the weight you like but you only have a small cross section of tyre for it to grip. Add another driven axle and you have twice the grip.

Take this clip for example

http://www.youtube.com/watch?v=pPE2lsSNK_8&pla...

Double drive wrecker tows a stuck single drive artic up the hill. Wouldn't have a cat in hells chance on its own and that's towing a reefer with a bloody great fridge unit above the driven axle.

Anyway, there's more chance of seeing these big trucks on the road now the EU want a Europe wide 14" height restriction which would mean the end for double deck trailers and contoured trailers to help with drag etc.

[jayfrancis]

GC8 said:

With diff locks and cross locks, yes: it certainly would. What you said may be perfectly correct when talking about driving exclusively on the road, but dual purpose vehicles (asphalt/aggregate tippers for example) do require dual drve and theyd be hobbled without it.

Posters suggesting that these over-weight combinations will be used for anything other than approved route trunking, deliveries to their local Tesco Mtro for example, are foolish.

The only issue that I can see, other than route closure; is that of recovery.

Ah someone who knows what there talking about.

I thought, like you that a double drive with cross and diff locks would be pretty well unstopable but after reading a very long thread on the trucknet forum most drivers agreed that if the going got slippery you would be better off with a single drive axle and either a tag or pusher axle. The thread was very long and contributiors included many quarry men, bulk refuse drivers etc and drivers from both sides of the atlantic. 99% of the time either will be fine but a double drive truck is less efficent, heavier and less manoverable and you're just a likely to get bogged down.

[Scuffers]

jayfrancis said:

I think you can. I just did and you agreed.

The more weight you can push down on one set of wheels the better it will grip. Fact.

Do you understand the difference between single and double drive?

sorry? at what point did I mention single drive?

My point is that 3 axle prime movers should have both axles driven, not the 'bodge' third axle setup that was introduced when we (stupidly) moved from 32tonne limits under the guise of 'spreading the load'

As for B-doubles on UK roads, every time the argument for heavier trucks comes up, the same old 'it will mean less trucks on the road' bks is spouted, it was not true then and won't be now.

B-Doubles (etc) make perfect scene in Aus, where they have huge mileages on straight roads though the middle of nowhere, but they are next to useless in urban environments.

[jayfrancis]

Getting back on topic I'd personally like us to follow what most European countries do. i.e 40 tonnes max on 5 axles and 14 foot height limit. This will protect jobs within the industry and keep things much simpler.

[Rollcage]

Road trains won't do smaller store deliveries as you could not practically unload them without a loading dock, which only the large superstores will have.

[jayfrancis]

Scuffers said:

sorry? at what point did I mention single drive?

My point is that 3 axle prime movers should have both axles driven, not the 'bodge' third axle setup that was introduced when we (stupidly) moved from 32tonne limits under the guise of 'spreading the load'

As for B-doubles on UK roads, every time the argument for heavier trucks comes up, the same old 'it will mean less trucks on the road' bks is spouted, it was not true then and won't be now.

B-Doubles (etc) make perfect scene in Aus, where they have huge mileages on straight roads though the middle of nowhere, but they are next to useless in urban environments.

So you think that all three axle prime movers should have both axles driven?


Absolute nonsense! Give me one reason for needing double drive on a normal tractor.

Double drives are much less efficent, use more fuel, harder to manovoure and cause more damage to the roads. There's 4 reasons why single drive is better.

Have you driven anything bigger than a car?

[GC8]

I would have supposed that a double drive would be more durable on the road, as the torque would be split over two differentials, in theory. With 500+BHP tractor units the torque will be phenomenal.

[jayfrancis]

Scuffers, take a read of this if you got a hour os so to kill and get the views of the people who do the job and use the equipment. You'll need to go in a few pages before the double drive debate begins.

http://www.trucknetuk.com/phpBB/viewtopic.php?f=2&...

Then you can come back and tell me about the laws of physics.

Edited by jayfrancis on Tuesday 1st February 22:38

[heebeegeetee]

Super Slo Mo said:

OP, you should write for the daily mail, with that sensationalist claptrap as your opening gambit.

That OP could not have come from anywhere other than the DM, i refuse to believe that anyone else could publish such alarmist claptrap.

I've been saying for years that PH expresses the same opinions as the DM but that OP is completely ridiculous.

[db]

jayfrancis said:

Scuffers, take a read of this if you got a hour os so to kill and get the views of the people who do the job and use the equipment. http://www.trucknetuk.com/phpBB/viewtopic.php?f=2&...

Edited by jayfrancis on Tuesday 1st February 22:38

my favourite quote from your chosen site

"Well, you see I don't actually know anything at all and just rely on advice given by people who do "

[poo at Paul's]

jayfrancis said:

Well I don't profess to know all the laws of physics.

But I know this. Whatever weight you have over your drive axle is going to be halved if you spread it over 2 drive axles. It's the weight that gives traction and if you halve it the wheels will spin even more. The non driving axle on single drive trucks can be lifted to increase weight on the drive axle hence more traction. There are some situations though when any truck will get stuck.

http://www.youtube.com/watch?v=P-FVBJw6En4&fea...

So does that all mean that a 2wd car has better traction than a 4wd version?

[streaky]

heebeegeetee said:

Super Slo Mo said:

OP, you should write for the daily mail, with that sensationalist claptrap as your opening gambit.

That OP could not have come from anywhere other than the DM, i refuse to believe that anyone else could publish such alarmist claptrap.

I've been saying for years that PH expresses the same opinions as the DM but that OP is completely ridiculous.

2005 - The 'Grauniad', and other papers;
2007 - The Daily Telegraph, and other papers;
2009 - The Times, and other papers;
2011 - email feed regarding EU proposals.

I don't take the Daily Mail.

A shame that the rest of you are not as widely read; it rather makes my point about history.

Streaky

[heebeegeetee]

streaky said:

heebeegeetee said:

Super Slo Mo said:

OP, you should write for the daily mail, with that sensationalist claptrap as your opening gambit.

That OP could not have come from anywhere other than the DM, i refuse to believe that anyone else could publish such alarmist claptrap.

I've been saying for years that PH expresses the same opinions as the DM but that OP is completely ridiculous.

2005 - The 'Grauniad', and other papers;
2007 - The Daily Telegraph, and other papers;
2009 - The Times, and other papers;
2011 - email feed regarding EU proposals.

I don't take the Daily Mail.

A shame that the rest of you are not as widely read; it rather makes my point about history.

Streaky

And did all those newspapers state that 2 to 3 of these 60 tonners will be arriving outside our convenience stores every day?

Why would anyone be alarmed by these vehicles, apart from ban-everything numpties? Why would fewer lorries cause operation stacks to be longer?

The only expense will be incurred by our respective governments who have all taken backhanders from the construction sector and have refused to build roads to the standards of the rest of Europe and will continue to refuse to build to forthcoming changes in regs.

Edited by heebeegeetee on Wednesday 2nd February 07:36

[jayfrancis]

poo at Paul's said:

So does that all mean that a 2wd car has better traction than a 4wd version?

But we're not discussing cars here. Trucks and cars are chalk and cheese.

Can you imagine the difference between a 2wd 911 with all the weight over the drive axle and an empty rwd Ford Fransit with no weight over the axle on a slippery surface? If you can you might just see what I'm getting at.