Saviem:
Evening all, well after a long day "harvesting " the HAY, I am conferonted by this…
ERF had a major problem with springing, (and vehicle stability) , therefore they located the springs outwards…as did most of the Europeans!
ERF had abysmilall stability prior to this, (short wheelbase, plus higher centre of gravity with an artic)… remember prior to 64, (Barbara Castle…everything was rigid…not artic)!
They tried to respond to a changing market…but Atkinson were in front of them…(but so where SOMUAO)…and who were they!!!
Cheerio for now.
I thought we were just interested in the facts of development here?.
ERF had no ‘major problems’ with vehicle stability - no more than any other manufacturer did at this time anyway. As UK legal weights were raised, the old chassis reached the limits of it’s design - as did every other manufacturers. A new design was tabled - in front of some, behind others.
Most 4x2 tractors on UK roads were running a circa 9’ 6" wheelbase at this time. Most had a 52" table deck height, and all had a very similar centre of gravity, including the European makes. Moving the rear springs outboard of the chassis rails greatly improves roll stability, but has quite a small effect on actual centre of gravity.
How exactly do you see that Atkinson were in front?. They had an excellent product all through the 1960’s, but all their senior engineers jumped ship to ERF around 1970, so ERF benefited from all their testing and design knowledge. This set Atkinson Vehicles back years in terms of manufacturer development, and some would argue they never again regained the reputation they once held within the market.
ERF:
…ERF had no ‘major problems’ with vehicle stability - no more than any other manufacturer did at this time anyway. As UK legal weights were raised, the old chassis reached the limits of it’s design - as did every other manufacturers. A new design was tabled - in front of some, behind others.
Most 4x2 tractors on UK roads were running a circa 9’ 6" wheelbase at this time. Most had a 52" table deck height, and all had a very similar centre of gravity, including the European makes. Moving the rear springs outboard of the chassis rails greatly improves roll stability, but has quite a small effect on actual centre of gravity…
Very interesting input, Mr. ERF. Most of the “technical” discussion on these forums concerns engines and gearboxes. The chassis of a lorry may just be, in principle, a crude ladder affair, but some work better than others.
Were anti-roll bars not popular in the 1960s? These would have improved the “stability” of the vehicle, without having to mess about with the spring attachment.
ERF:
…ERF had no ‘major problems’ with vehicle stability - no more than any other manufacturer did at this time anyway. As UK legal weights were raised, the old chassis reached the limits of it’s design - as did every other manufacturers. A new design was tabled - in front of some, behind others.
Most 4x2 tractors on UK roads were running a circa 9’ 6" wheelbase at this time. Most had a 52" table deck height, and all had a very similar centre of gravity, including the European makes. Moving the rear springs outboard of the chassis rails greatly improves roll stability, but has quite a small effect on actual centre of gravity…
Very interesting input, Mr. ERF. Most of the “technical” discussion on these forums concerns engines and gearboxes. The chassis of a lorry may just be, in principle, a crude ladder affair, but some work better than others.
Were anti-roll bars not popular in the 1960s? These would have improved the “stability” of the vehicle, without having to mess about with the spring attachment.
A roll bar isn’t there to/won’t solve the same problem as a chassis to axle attachment that’s too far in board.The former is all about controlling movement between the the chassis and axles in roll which affects the way the wagon handles from the driver’s point of view.However the latter is about fulcrum and leverage affects of the chassis as delivered at the wheels.IE sideways force on the body gets translated into a lifting effect at the wheels on the opposite side to that which the the body is leaning and the wheels on the side of the lean acting as the fulcrum point.The closer that the chassis/axle attachment point is to those wheels on the side of the lean the less the leverage effect at the fulcrum point ( wheels ) will be.Therefore less lifting effect on the opposite side.I’d guess that stiffening the roll resistance between body and axle while leaving that attachment point further inboard away from the wheels would actually make matters worse not better.
Carryfast:
A roll bar isn’t there to/won’t solve the same problem as a chassis to axle attachment that’s too far in board.The former is all about controlling movement between the the chassis and axles in roll which affects the way the wagon handles from the driver’s point of view.However the latter is about fulcrum and leverage affects of the chassis as delivered at the wheels.IE sideways force on the body gets translated into a lifting effect at the wheels on the opposite side to that which the the body is leaning and the wheels on the side of the lean acting as the fulcrum point.The closer that the chassis/axle attachment point is to those wheels on the side of the lean the less the leverage effect at the fulcrum point ( wheels ) will be.Therefore less lifting effect on the opposite side.I’d guess that stiffening the roll resistance between body and axle while leaving that attachment point further inboard away from the wheels would actually make matters worse not better.
^ Considering the geometry I’m referring to and what happens when you increase the roll resistance between chassis and axles ( IE you just transfer the movement directly to the axles in a similar way as using solid suspension would ) maybe some actual reasoning as to which bit I’ve got wrong would be interesting.
So are you saying that delivering a sideways force,to the the vertical part of the left hand side of an L shape,won’t translate to a lifting force from the left at the base of the L shape assuming it’s right hand end is an anchored fulcrum point and that lifting force won’t increase with the length of the base of the L relative to the vertical part.
Yes that’s correct, but as usual you’re only focusing on one part of an equation. You still have the load exerting a downward force and you’re completely forgetting about center of gravity. It’s the center of gravity passing a certain point that will lift a wheel, taking the springs further towards the wheels will lower the center of gravity and allow much higher roll angles without going to the point of no return.
Stiffening things up will help at low speeds, but when the centrifugal forces overcome the downward force of the load it will fall over.
newmercman:
Yes that’s correct, but as usual you’re only focusing on one part of an equation. You still have the load exerting a downward force and you’re completely forgetting about center of gravity. It’s the center of gravity passing a certain point that will lift a wheel, taking the springs further towards the wheels will lower the center of gravity and allow much higher roll angles without going to the point of no return.
Stiffening things up will help at low speeds, but when the centrifugal forces overcome the downward force of the load it will fall over.
The centre of gravity and the load are effectively as close as makes no difference in all cases.IE you don’t change the centre of gravity ( body and load height ) by shifting the chassis to axle attachment points nearer to the wheel and the body and the load is the load.In the case of shifting the chassis to axle attachments nearer to the wheels,just I said you cut the amount of torque acting around the fulcrum made by the wheels on the side that’s leaning and therefore the amount of corresponding lifting force acting on the opposite side.
IE in the case of an L shaped lever the torque figure around the fulcrum,being the wheels in this case at the end of the base of the L,is based on the sum of the length of both the base of the L and the vertical side of it.In which case shortening the length of the base of the L reduces that torque figure hence the amount of lift at the opposite side hence you’ve increased the thing’s capacity to accept either a higher centre of gravity or more centrifugal force.As for roll bars they obviously stiffen up the resistance to roll between chassis and axle at the expense of sending more of the rolling forces/angles to the axles/wheels.
In which case the worst of all worlds would be a longer distance between the wheels and chassis to axle attachments together with a stiffer roll resistance set up.IE the thing would have less tolerance to rolling either through centrifugal force or height of the centre of gravity or combination of both.Hence the correct idea of shifting the attachments outward.
Pat Kennett added to this equation the ‘pendulum’ effect. I’m not sure how this impacts upon the immediate discussion in hand, but it would be interesting to know whether or not the position of suspension (outboard or inboard) would make any difference to the pendulum effect. I reproduce his short piece on the subject (from Better Driving, published by T&D) below. Robert
Now, may we get back to the specifics of ERF chassis design, without boring the life out of those who might have actual information on the subject, please?
robert1952:
Pat Kennett added to this equation the ‘pendulum’ effect. I’m not sure how this impacts upon the immediate discussion in hand, but it would be interesting to know whether or not the position of suspension (outboard or inboard) would make any difference to the pendulum effect. I reproduce his short piece on the subject (from Better Driving, published by T&D) below. Robert
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There was a lot of good information going around in those better days.I can remember a very interesting article related to the issue of slow speed roll overs whereas now drivers seem to be taught that so long as they go slow enough then nothing can go wrong.In general cutting the pendulum effect is as much,if not more,about what is done at the wheel by pausing in the straight ahead position for as long as possible between changes of lock from left to right,than the accelerator.
Now, may we get back to the specifics of ERF chassis design, without boring the life out of those who might have actual information on the subject, please?
The difference being that in the case of cars with their combination of lighter weight and low centre of gravity a stiffer roll set up will result in exchanging roll between body and wheels for mostly more lateral G loading at the wheels.In the case of a truck it’s more a case that a stiffer set up in terms of roll between chassis and axles will result in more of a vertical loading at the wheels.When you combine that with a long distance between the wheels and the chassis to axle attachments you’re obviously going to produce more lifting tendencies on the unloaded side under roll conditions.
Well here’s an opportunity to segue into another topic that is both specific to the ERF NGC and general to ERFs: the issue of 13-speed Fullers. I recently posted an article by Pat Kennett on my ‘Lorries with 13-speed Fuller gearboxes’ thread, which explains why in some makes of lorry the splitter is actuated by the clutch and in other makes it isn’t necessary (ie clutchless split-shifts). Briefly, if the splitter switch is connected directly to the servo you can make clutchless changes, but if the splitter switch is routed via the clutch servo to the transmission servo you need to dip the clutch to actuate the change. It’s all clearly described in the article, which I’ve reproduced below.
However, I’ve only ever driven older ERFs with 9-speed Fullers or 12-speed Twin-splitters so I don’t know which route ERF used with it’s '70s 13-speed Fuller 'boxes. Does anyone know whether ERF NGCs with 13-speed Fullers, or indeed the LHD B-series units that followed them, had direct or indirect actuation? Robert
3300John:
Hiya Robert…my 13 speed right hand drive big cam ■■■■■■■ 290… B series you could drive all day long without using the clutch.
don’t know if that,s any use to you…i know its about opposite everything you asked.
John
John, you’ve told me precisely what I wanted to hear! If the B-series had a direct connection 13-speeder, then there’s a good chance that the NGC did too. Gary Corbishley’s has a 13-speed 'box so perhaps he can tell us. Fingers crossed. Cheers! Robert
Jazzandy:
Sorry to use this thread for a message but need to contact En-Tour-Age urgently with the following :-
Hi there En-Tour-Age,
Wonder if you can help me. In the early 70’s I used to have my Mack R600 truck serviced at Van Hove in Brussels before they moved to Kobbegem. I am writing a thread called ‘My First Continental Job’ and I am stuck for the address of their original premises. It was in one of the suburbs but if you can locate it for me I would be very grateful!
Andy
Jazzandy…I am afraid I can only confirm the message from Mandator but I asked some colleagues on more info, even a sight
of the buildings from Van Hove, which might illustrate your magnificient story a lot! A humble suggestion…print the novel and
check where good pictures or maps (on situations/locations) are available and you could publish your genuine story!
