hello allan,im not trying to be rude im just stateing fact.now as far as im aware "just winding LSV valves in "is the most irrisponceible thing ive ever heard of.this is a factor in a lot of accidents due to overbraking.LSV should be checked in three conditions.im sure you,ll know this.now before my TIME we had anti jack knife plates,but what we did,nt have was A,LSV,S and B,TRAILER CONTROL VALVES WITH BUILT IN PREDOMENANCE.(a trailer dosnt make a unit jack knife,locking rear axle on a unit does). also if its an old unit unladen you can expect 3 bar empty and between 8 and 9 bar at the chambres if its loaded .its proportional braking,the 50% i quoted was effort ,nothing else.then we move to present day,ABS thing of the past,EBS is the norm now.were not waiting for air to move now,its done electronically-can data bus.quicker than the blink of an eye.individual wheel braking.total safety.loaded or empty the braking distance shouldnt differ but brake effort will get greater.it has to or the vehicle wouldnt be safe.and as you say the other 200%which actually isnt,is taken in too account with increased air pressure ,in turn more effort.and im sorry if ive come over rude .
when towing, remember the extra length will affect overtaking and manoeuvring. The extra weight will also affect the braking and acceleration.
Sound Advice, Taken from the latest edition of the Highway code, I dont think we can argue with that can we?
Allan.
ps cant realy make a lot of sense from your last post Seth.
Sound Advice, Taken from the latest edition of the Highway code, I dont think we can argue with that can we?
Allan.
ps cant realy make a lot of sense from your last post Seth.
thats funny Allan,you should do .you sound like your up to speed on it all.brake pressures,wieghts and stuff.you call me misleading .ive said the facts how you interprete them is down to you.i let certain people on here waffle on in their little bubble.by the way im at a loss as to what you do for a living.thanks seth
VEHICLE WEIGHT BRAKING DISTANCE (m)
30 MPH 45 MPH
DAF Crew Cab (Laden) 11.6 Tonnes 15.09 34.62
Picasso 1.3 Tonnes (ABS) 7.26 18.00
Mondeo 1.4 tonnes (no ABS) 7.14 25.36 (19.7
and you quote John L :
But let us first consider the size of brake mechanisms. In essence if a vehicle is designed to have an all up mass of 1T then brakes of an appropriate surface area will be fitted. If the vehicle is designed for 2T then the brakes will require twice the surface area to achieve the same rate of retardation. The same principal applies all the way up to 44Tonners. Thus in theory it should be possible for a 44T to stop in the same distance as a 1T car.
Safety Advice
The advice provided in the Highway Code recommends that drivers give large goods vehicles (LGV) more room in which to stop. The issue is how much room do they need?
Answer: Experimental Demonstration
The braking distance of a range of vehicle types was compared both at 30 and 45 mph. This illustrated that LGVs can need up to three times the distance in which to stop when compared to a car.
However, a higher level of retardation may not be welcomed by drivers hauling 25 tonnes of steel rods positioned one metre away from their back. They will always obey Newton's Laws and will want to keep going at the pre braking speed. That in itself causes health and safety problems.
So there you have it: increase the mass, increase the stoping distance, Simple Newtons law.
Allan.
30 MPH 45 MPH
DAF Crew Cab (Laden) 11.6 Tonnes 15.09 34.62
Picasso 1.3 Tonnes (ABS) 7.26 18.00
Mondeo 1.4 tonnes (no ABS) 7.14 25.36 (19.7
and you quote John L :
But let us first consider the size of brake mechanisms. In essence if a vehicle is designed to have an all up mass of 1T then brakes of an appropriate surface area will be fitted. If the vehicle is designed for 2T then the brakes will require twice the surface area to achieve the same rate of retardation. The same principal applies all the way up to 44Tonners. Thus in theory it should be possible for a 44T to stop in the same distance as a 1T car.
Safety Advice
The advice provided in the Highway Code recommends that drivers give large goods vehicles (LGV) more room in which to stop. The issue is how much room do they need?
Answer: Experimental Demonstration
The braking distance of a range of vehicle types was compared both at 30 and 45 mph. This illustrated that LGVs can need up to three times the distance in which to stop when compared to a car.
However, a higher level of retardation may not be welcomed by drivers hauling 25 tonnes of steel rods positioned one metre away from their back. They will always obey Newton's Laws and will want to keep going at the pre braking speed. That in itself causes health and safety problems.
So there you have it: increase the mass, increase the stoping distance, Simple Newtons law.
Allan.
There you are Seth, the facts, and not miss leading ones, or can you argue against Rospa?
Allan.
Allan.
The general principle of heavier vehicles needing more room to stop was supported in subsequent test conducted at the Army's driver training facility at Leconfield.
and finaly John L
So a partially loaded vehicle will have over sensitive brakes and a reduced road contact area that will prevent maximum braking efficiency from being achieved, the result is evident in longer stopping distances, and witnessed by the number of skid marks made by unladen trailers when approaching junctions.
Iveco tractor and trailer Unladen* 17.70
Iveco tractor and trailer Laden* 42 tonnes (ABS) 27.00
Seat medium family saloon* 8.50
So as you can see John it takes almost a further 10mtrs to stop the laden Iveco tractor and Trailer not vis versa.
Sorry to have gone on so much. Allan
and finaly John L
So a partially loaded vehicle will have over sensitive brakes and a reduced road contact area that will prevent maximum braking efficiency from being achieved, the result is evident in longer stopping distances, and witnessed by the number of skid marks made by unladen trailers when approaching junctions.
Iveco tractor and trailer Unladen* 17.70
Iveco tractor and trailer Laden* 42 tonnes (ABS) 27.00
Seat medium family saloon* 8.50
So as you can see John it takes almost a further 10mtrs to stop the laden Iveco tractor and Trailer not vis versa.
Sorry to have gone on so much. Allan
- Mar 14, 2005
- 18,980
- 4,204
- 50,935
Hello Allan,
I deliberately did not refer to LCV's and ABS because they should both enhance a system rather than detract. ABS especially should only come into play if the driving situation requires emergency braking. That is then a different issue and calls into question the drivers ability to read the road conditions.
Now lets consider what this thread is rally trying to establish. On the one hand there is the perception that cars with caravans, and HGVs need a longer distance to stop than a solo car or an unloaded HGV. This validity of this view is claimed because the Highway code and other interested organisations suggest it is wise to give laden vehicles greater room for manoeuvres such as braking. it is an advisory statement, if it were necessary than it would be worded differently. The advice is not wrong, but it may not be necessary.
The other view to which I subscribe is that the loading of a vehicle can actually improve braking performance. Though in fact it more likely improves the interaction of the tyre and road allowing improved grip.
There is room for both views and they are not mutually destructive. There is nothing wrong in allowing greater manoeuvring room for a laden vehicle. If nothing else it is a courtesy.
I deliberately did not refer to LCV's and ABS because they should both enhance a system rather than detract. ABS especially should only come into play if the driving situation requires emergency braking. That is then a different issue and calls into question the drivers ability to read the road conditions.
Now lets consider what this thread is rally trying to establish. On the one hand there is the perception that cars with caravans, and HGVs need a longer distance to stop than a solo car or an unloaded HGV. This validity of this view is claimed because the Highway code and other interested organisations suggest it is wise to give laden vehicles greater room for manoeuvres such as braking. it is an advisory statement, if it were necessary than it would be worded differently. The advice is not wrong, but it may not be necessary.
The other view to which I subscribe is that the loading of a vehicle can actually improve braking performance. Though in fact it more likely improves the interaction of the tyre and road allowing improved grip.
There is room for both views and they are not mutually destructive. There is nothing wrong in allowing greater manoeuvring room for a laden vehicle. If nothing else it is a courtesy.
It is a proven fact that braking distance is actually shorter when towing a trailer than when the car is solo (on condition that both the car's brakes and those of the caravan are properly adjusted and maintained (Lutz)
I asked originally who had proven this fact, and when, as I find it very misleading and dangerous to make such a sweeping statement, but nobody has given me the proof to back up this theory, so all I have done is to reinforce Newton's theory beyond a shadow of a doubt and given the hard facts that are not disputable:simple increase mass increase the stopping distance and the energy to do it, not wishing to be offensive but it just seems that some people never know when to lie down, even when faced with solid evidence from Rospa.
I asked originally who had proven this fact, and when, as I find it very misleading and dangerous to make such a sweeping statement, but nobody has given me the proof to back up this theory, so all I have done is to reinforce Newton's theory beyond a shadow of a doubt and given the hard facts that are not disputable:simple increase mass increase the stopping distance and the energy to do it, not wishing to be offensive but it just seems that some people never know when to lie down, even when faced with solid evidence from Rospa.
Some years ago one the the caravan mags tested stopping distances of cars with ABS and cars without, both towing and solo. The shortest stopping distance was achieved by the car with ABS towing a caravan.
Allan, sorry to have to post this for a third time but I have seen the test results Lutz is refering to and I see a post from Richard S confirming he has also seen them.
Brian (",)
Some years ago one the the caravan mags tested stopping distances of cars with ABS and cars without, both towing and solo. The shortest stopping distance was achieved by the car with ABS towing a caravan.
Allan, sorry to have to post this for a third time but I have seen the test results Lutz is refering to and I see a post from Richard S confirming he has also seen them.
Brian (",)
Allan, sorry to have to post this for a third time but I have seen the test results Lutz is refering to and I see a post from Richard S confirming he has also seen them.
Brian (",)
Facts please,under what conditions, etc to back your theory,if you are going to have a debate then please pre arm yourself with all the relevent facts, not third hand information that no one seems able to substantiate.
I have posted my facts as proven by Rospa, and if needs be there is a whole welth of information that I could post on the subject, but I wont, as far as I am cocerned this subject is closed.
I have posted my facts as proven by Rospa, and if needs be there is a whole welth of information that I could post on the subject, but I wont, as far as I am cocerned this subject is closed.
Not my theory and I'm not having a debate I,m just saying that a magazine carried out a test and the results were as I,and two others,have stated .
"Not my theory and I'm not having a debate(thought that's what forums were for) I,m just saying that a magazine carried out a test and the results were as I,and two others,have stated"
1, what magazine? Can't be that difficult, three of you have read the article!
2, what test, and under what conditions?
3, what exactly were the results?.
4, If you are going to make a "statement" you must have the facts readily available to prove your point.
I have proven my point, with concrete evidence, please do likewise. It is not rocket science, just the law of physics.
I don't doubt that some sort of test was reported on, (most probably under track conditions) ,but I would doubt very much that they would advocate using there findings as a general rule of thumb on a public highway, so please let's let common sense prevail and take it as fact, and as I have proven, that if you increase the load you increase the stopping distance, and if we all apply that rule we will be that bit safer when we tow our caravans.
Allan.
1, what magazine? Can't be that difficult, three of you have read the article!
2, what test, and under what conditions?
3, what exactly were the results?.
4, If you are going to make a "statement" you must have the facts readily available to prove your point.
I have proven my point, with concrete evidence, please do likewise. It is not rocket science, just the law of physics.
I don't doubt that some sort of test was reported on, (most probably under track conditions) ,but I would doubt very much that they would advocate using there findings as a general rule of thumb on a public highway, so please let's let common sense prevail and take it as fact, and as I have proven, that if you increase the load you increase the stopping distance, and if we all apply that rule we will be that bit safer when we tow our caravans.
Allan.
I have no doubt that when Lutz returns home he will be able to give details of when and where the article was published.
- Mar 14, 2005
- 10,093
- 909
- 40,935
Until I can lay my hands on the report, here are the details from memory:
1. Towcar equipped with ABS and laden to its GVW
2. Caravan laden to its MTPLM (Brakes did not lock. They only lock when unladen because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition)
3. Dry road surface with good grip
1. Towcar equipped with ABS and laden to its GVW
2. Caravan laden to its MTPLM (Brakes did not lock. They only lock when unladen because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition)
3. Dry road surface with good grip
because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition)
Very true Lutz, but Newtons law can.
Very true Lutz, but Newtons law can.
Just to add another note. Because caravan brakes are not equipped with ABS (yet), you will find that their performance is normally "good enough to lock the wheels even on a dry road surface during an emergency brake and you can't expect more than that"
2. Caravan laden to its MTPLM (Brakes did not lock. They only lock when unladen because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition)
Contradiction in your statement there Lutz.
2. Caravan laden to its MTPLM (Brakes did not lock. They only lock when unladen because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition)
Contradiction in your statement there Lutz.
because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition)
if thats not Contradiction what is? Or do you have a little word with the caravan & tell it what state it is in............Lol
Allan.
if thats not Contradiction what is? Or do you have a little word with the caravan & tell it what state it is in............Lol
Allan.
- Mar 14, 2005
- 10,093
- 909
- 40,935
It should stand to reason that the heavier the van, the less likely the brakes will lock up and optimal braking will alwys be achieved just before they lock up. Therefore, braking performance should ideally cater for a compromise situation. In the case of ABS, this is done automatically.
The same goes for the car. ABS automatically reduces the braking performance on the rear axle and increases that at the front as there is a weight transfer from back to front under braking. Otherwise, the rear brakes would always lock up first. The noseweight is a partial offset to this weight transfer, allowing the rear brakes to do more work.
The same goes for the car. ABS automatically reduces the braking performance on the rear axle and increases that at the front as there is a weight transfer from back to front under braking. Otherwise, the rear brakes would always lock up first. The noseweight is a partial offset to this weight transfer, allowing the rear brakes to do more work.
- Mar 14, 2005
- 10,093
- 909
- 40,935
Because you can't have a 'little word with the caravan', as you put it, the brakes will be designed to be just a little too powerful when the caravan is empty (i.e. brake lock occurs) and just short of locking when the caravan is fully laden. If caravans had their own ABS or load sensitive braking, one could even automatically adjust their braking system performance accordingly.
"No contradiction because, with an ideal setup, the braking performance will be such that the brakes will just start to lock when the caravan is empty and just not lock when the caravan is laden".
"because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition")
"good enough to lock the wheels even on a dry road surface during an emergency brake and you can't expect more than that"
"The same goes for the car. ABS automatically reduces the braking performance on the rear axle and increases that at the front? as there is a weight transfer from back to front under braking. Otherwise, the rear brakes would always lock up first.
Confusing this with EBD
Stay with the subject matter, increased weight increased stopping distance as proven beyond doubt by rospa.
Clasic case of the hole geting biger!
Allan.
"because for lack of load proportional brake distribution on the caravan, caravan brakes are unable to distinguish between the laden and unladen condition")
"good enough to lock the wheels even on a dry road surface during an emergency brake and you can't expect more than that"
"The same goes for the car. ABS automatically reduces the braking performance on the rear axle and increases that at the front? as there is a weight transfer from back to front under braking. Otherwise, the rear brakes would always lock up first.
Confusing this with EBD
Stay with the subject matter, increased weight increased stopping distance as proven beyond doubt by rospa.
Clasic case of the hole geting biger!
Allan.
- Mar 14, 2005
- 10,093
- 909
- 40,935
No, no confusion with EBD. That is something completely different. That effectively increases pedal pressure in the event of an emergency. I'm talking about pure load proportioning of braking performance.
Although the caravan brakes, due to lack of load proportioning, cannot be absolutely optimal for all conditions, the improvement that the added noseweight gives to the rear brakes of the car more than compensates for this shortcoming.
Although the caravan brakes, due to lack of load proportioning, cannot be absolutely optimal for all conditions, the improvement that the added noseweight gives to the rear brakes of the car more than compensates for this shortcoming.
You keep going around in circles Lutz, look at the word: Anti Lock Braking System:Sensors monitor the wheels, when they see no movement, pulses the brake on and off,to reduce the possibility of a skid. But as previously stated stay with the subject matter, and supply the proof to back up your statement of a shorter stopping distance towing a caravan, than opposed to a solo car.
Allan.
Allan.
Facebook
Twitter