Noseweight advice
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where was the phrase "shove it" used. I have been towing for only 5 months and I know that I need to weigh the nose every time I tow, before I go to and return from site. everybody should know what the max is for their vehicle and for their van. I make sure that the weights are as near to accurate as poss even if that takes an extra 30 mins before I leave because its for my and my wife's safety and all the other road users.
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only changes (decreases) as the hitch is raised and increases as the hitch is lowered,
You are being a bit too 'cavalier' for my liking here with your terminology here and jumping to a conclusion which is correct but misses out a lot of physics/maths. In effect you are describing the effect on the towball and car not what actually happened to the nose weight.
The actual nose weight (static as you call it) is caused by the turning moment of the end of the hitch around the CoM of the van and (like any moment) is the product of the vertical force there (weight) multiplied by the perpendicular distance to that force. So when the van is horizontal this causes the maximum moment and hence nose weight. If the hitch is raised or lowered then the horizontal distance is reduced (by the cosine of that angle) and hence the nose weight decreases and decreases the same amount for the same angle above raised or lowered. This is the ‘fact’ as proved using maths and physics. This is what happens when there is no car (Try it with your van using the jockey wheel and bathroom scales)
However when connected to a tow ball, when the van/tow ball is raised it pulls the back of the car up and hence the perceived nose weight as ‘felt by the car’ decreases. When the towball is lowered and the van is nose down the van pushes down on the back of the car and the car ‘feels’ extra nose weight and it increases.
So you are correct but you are describing the effect of the nose weight on the car, not what actually happens to the nose weight.
In effect (pun intended) we are just looking at it from two different viewpoints (mathematician v engineers?)
PS hope this hasn't upset your day LL
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before I go to and return from site
what do you do or take out on site that would affect the nose weight?
BTW very commendable and you can never be too safe so not any criticism at all , I haven't seen many people, actually can't think of any checking nose weight when they leave a site
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lol
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I'm afraid I don't follow your reasoning. Noseweight is the vertical load applied to the towball on the towing vehicle. The 'perceived' noseweight, as you call it, is the actual noseweight. It is that which determines whether the integrity of the towbar and the underbody structure of the towing vehicle are up to the job that they are called upon to do.
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The closest I've seen to nose weight being checked was at Moreton-in-Marsh a few years ago, a little fella trying to lift the A frame/hitch of his caravan. I asked if he'd calibrated his back recently ..... it went way over his head
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I must admit doing the same. I measure the noseweight accurately now and again just to get the feel of what it should be and from then on if it feels right by lifting the hitch by hand, it's good enough by me. I would think that I'm able to be within ±5kg and that's about as accurate as some gauges on the market.
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I would have thought a nose weight gauge would be cheaper than the osteopaths bills.
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well I have checked my reasoning with other competent physicists and they agree, I assure you it's correct. You are just jumping to the end result that's all, a correct one but without the full story. Suggest you look here: https://caravanchronicles.com/guides/understanding-the-dynamics-of-towing/
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but all you are doing is supporting the van, did you notice a difference btw as you lower and raise through the horizontal as you predict it would ? or did it feel the same? Simple Newtonian physics says it must be the same. Is this some war against Newton? I know you Germans think that Leibniz invented Calculus but this is taking things too far
the van when pointing upward is not trying to raise you as it would when connected to a towball is it? Think about it if it's nose up the hitch must take tow ball with it and take some weight off the car's tyres? QED again
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yes you correct, not the play on words but the way nose weight is interpreted. Is it part of a bigger system, or does it exist by itself. Both.
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Within reasonable limits, the difference in noseweight between noseup and nosedown on a longish caravan is typically not large and only just noticeable by hand, but in the case of my short tarpaulin trailer, if I raise the hitch high enough, the noseweight actually reduces to such an extent that it turns negative as the CoM moves from ahead of the axle to just behind. The trailer will then remain nose up until physically pulled down again when the noseweight returns to its normal value.
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well the nose weight cannot, cannot disappear, the hitch exists , it has a mass, and therefore it is affected by gravity, now what you are saying is that the effect of the nose weight on the tow ball might be zero but it will still be there supported somewhere else. In the same way that tension in a tow bar might be zero overall (with a +T in the direction of travel and -T the opposite) when travelling at a constant speed but taking the tension on the car and trailer separately the tensions still exist.
Or if you're like me you stand on the bathroom scales and flinch with horror, what do you do? lean and push up on the on the sink and what happens to the reading ? It goes down, I could actually push harder and get a zero reading! Has my weight gone? No of course not, it merely has been supported somewhere else. Same idea as your example above
But if you have found a way of making a mass become weightless get in touch with NASA
I think we look at things in different ways, you look at the end result, I look at individual forces.
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Of course the noseweight can't disappear. The total weight of the trailer remains constant. It is the sum of the noseweight and the axle load. Therefore, if the hitch is raised so high that the trailer remains nose up due to the CoM being at or behind the axle, all the load is transmitted through the axle and none through the hitch. The noseweight at that point is zero and the hitch actually needs to be pulled down to bring it to towball height.
In other words, as the noseweight goes down, the axle load goes up.
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So you retract your previous statement?
the noseweight actually reduces to such an extent that it turns negative
(To turn from positive to negative it has to go through zero)
again it is the effect of the noseweight that appears zero not the noseweight itself. For me you are not being precise enough and while I understand what you are trying to say, it could be misleading to others to think that they could make their noseweight 'dissapear'
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No, i'm not retracting any statement. I need to hold the hitch down (negative noseweight) in order to stop the back of the trailer touching the ground. Once the back is actually touching the ground I can obviously release the hitch and then the noseweight is zero.
To put it another way, when hitched to the car, the total weight of the trailer is the axle load plus the noseweight acting on the towball. When the unhitched and the nose raised so high that it stays there, the total weight of the trailer is the axle load plus whatever the back of the trailer exerts on touching the ground (and no noseweight). Just before the back of the trailer is touching the ground the noseweight is negative because it is acting upwards.
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once again you cannot change the laws physics, laws of physics....
you know how the song goes?
Here is an idea of what you are saying in a different format. A heavy chap (possibly me) sits on a see saw. A very light baby sits at the other end (please no H&S comments) what happens? The baby is held up in the air just like your caravan. Now the weight of the man and see saw is taken on the pivot and the man touching the floor. According to you the baby has now zero weight? The weight of the baby is zero? really?
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But the baby and the heavy chap are both part of the total weight of the see saw. You need to physically pull the end of the see saw where the baby is sitting down in order to get the see saw level again and that is the noseweight. As long as you leave the baby in mid air no force is being applied at the baby's end and therefore there is no noseweight.
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I think its now a play on words and interpretation, but interesting nonetheless.
