Nose weight and pitching

[Buckman]

Nose weight is not very accurate even using bathroom scales. It does not matter if it is a couple of kg out either side. When traveling, the nose weight could fluctuate between zero and plus 200kg depending on the state of the road.

However it has been recommended to go for the maximum nose weight allowed by the towbar or the maximum 100kg for the caravan tow hitch..

 

[Beardy]

We are new to caravanning, having bought our 2017 Bailey Pegasus Genoa 4 just a few weeks ago. Our tow car is a VW Tiguan 2.0 diesel. The target nose weight according to Towsafe is between 63 to 89 kg (5% - 7%) but on our first short trip last week I was only able to get up to just under 70kg. It was my first time towing and I did not feel secure with the drive - I think the van was pitching - tugging and pushing at the car. Is that a normal feeling or do I need to sort the nose weight out?

If you search out my introduction post from a few weeks ago I had a very similar experience to you. It almost felt like the car was slightly 'kangarooing' at low speeds on uneven roads. It was rock solid at 50-60 mph on the motorway. Being new to caravan towing like yourself I wasn't sure if this was normal. Increasing the nose weight from 75 to 90kg made it slightly better, but in my case my hitch damper was shot. If you chock the wheels and release the handbrake you should be able to compress the hitch damper. It should move very slowly and it takes a lot of effort. When you release it it should extend very slowly (mine sprung back instantly). Having replaced the damper I can still feel the caravan pushing and pulling the car very slightly, but it's nothing like it was. I've read that you can feel something similar if the brakes aren't correctly adjusted.

 

[ProfJohnL]

Nose weight is not very accurate even using bathroom scales. It does not matter if it is a couple of kg out either side. When traveling, the nose weight could fluctuate between zero and plus 200kg depending on the state of the road.

However it has been recommended to go for the maximum nose weight allowed by the towbar or the maximum 100kg for the caravan tow hitch..

Both the caravan and car manufacturers know about the effects of towing on the the actual dynamic loads that can be developed on the hitch, and they have taken them into account when specifying the capability of the hitch and towbar systems.

It is simply not possible for the normal trailer owner to measure the actual dynamic loads, so the the industry suggest a maximum static load which can be measured with reasonable accuracy. The value has been chosen so that it should not exceed to safety margins when under normal towing conditions.

The heavier the static nose load is the more of that safety margin headroom is eroded and there will be more wear and tear on things like the panel work the tow bar is attached to. The effect of vibrations is to multiply the force any mass produces on it support structures, so if you double the nose load it will produce twice the impact loading that any vibrations cause on the assembly.

As far as I know there isn't any formal recommendation to work a hitch as close to its maximum allowed. Please feel free to post evidence of it. I know there are a small number of caravanners who swear by it , but they are not the majority.

The formal recommendation is to aim for between 5 and 7% and as we know from posts on this and other forums, many caravans have difficulty getting up to this percent, either because of lower towbar limits or the ability to trim the loading of the trailer.

 

[Lutz]

I cannot believe that a 10kg variation in noseweight either way is going to affect the behaviour of the caravan appreciably when it's towed, I have towed my 1800kg caravan from where it's stored to home before it's loaded up. In that condition that it probably has no more than 25kg on the hook and yet it's only marginally worse to tow. It certainly doesn't pitch any more than when the noseweight is set up properly. There is only a slight sensation of yawing movement.

 

[Hutch]

I cannot believe that a 10kg variation in noseweight either way is going to affect the behaviour of the caravan appreciably when it's towed, I have towed my 1800kg caravan from where it's stored to home before it's loaded up. In that condition that it probably has no more than 25kg on the hook and yet it's only marginally worse to tow. It certainly doesn't pitch any more than when the noseweight is set up properly. There is only a slight sensation of yawing movement.

I would tend to slightly disagree with you. When in the upper limits of the Alko tow hitch of 100 kg. Then when around the 80 kg weight, I can certainly feel a difference in towing my 1645kg Coachman . Depending on how my wife has loaded the fridge I will move the nose weight to be heavier on the way out when on the way home I will lighten the nose load as the van will have a different towing characteristic.
Also the roads will change your towing. As against the length of your outfit. The worst road for me is the A68 from Edinburgh to Otterburn. Totally pitching and yawing, due to the road and the size of my outfit.

 

[RogerL]

Both the caravan and car manufacturers know about the effects of towing on the the actual dynamic loads that can be developed on the hitch, and they have taken them into account when specifying the capability of the hitch and towbar systems.

It is simply not possible for the normal trailer owner to measure the actual dynamic loads, so the the industry suggest a maximum static load which can be measured with reasonable accuracy. The value has been chosen so that it should not exceed to safety margins when under normal towing conditions.

The heavier the static nose load is the more of that safety margin is eroded and there will be more wear and tear on things like the panel work the tow bar is attached to. The effect of vibrations is to multiply the force any mass produces on it support structures, so if you double the nose load it will produce twice the impact loading that any vibrations cause on the assembly.

As far as I know there isn't any formal recommendation to work a hitch as close to its maximum allowed. Please feel free to post evidence of it. I know there are a small number of caravanners who swear by it , but they are not the majority.

The formal recommendation is to aim for between 5 and 7% and as we know from posts on this and other forums, many caravans have difficulty getting up to this percent, either becasue of lower towbar limits or the ability to trim the loading of the trailer.

The "formal" recommendation only came about because the hitch restriction on most UK caravans and UK/EU cars means that very few can go above 7% anyway - it's not based on scientific or technical research.

Provided that none of the limits are exceeded, there's no reason to suggest that lower noseweights provide a "better" margin.

Anecdotally most caravanners have issues reducing their noseweight down within limits but a few (of us) have difficulties getting the noseweight up to an acceptable level.

 

[trevormonty]

Hi we have a Bailey Phoenix 420 which is a small van.
Due to its design. we have to load everything up front on or near the center drawer. awning chairs clothes, etc and we make sure we have the heater unit filled with water, we can fine-tune with water ballast in the water barrel to get to around75kg nose weight, Without this lot the van tips up when using the motor mover
we also tow with a Tiguan 2.00 diesel which gives a good controlled tow.
hope this helps a littleM

My first experience towing caravan was hire 420. Was dog to tow and never forgot it was there, any slight undulations in road eg joins on bridge and it would pitch up and down. On return to rental place discovered they placed rocks and spare 28kg battery in nose to make sure it had enough down mass. Never weight but judging by how far my suspension dropped on hook up suspect it was well over cars 75kg limit. We bought older shorter slightly lighter ( 1000 vs 1150) van day after returning rental. Down mass considerably less, result was lot more pleasant towing experience. I've not weigh down mass but suspect its around 50kg and never felt need to go heavier.

420 was nice van but lack of front locker to stow all setup stuff was big negative. Putting wet and dirt ground sheets under bed isn't ideal. Could us gas locker if only running one cylinder.

ProfJohn. Good point on waterheater, I typically empty it to reduce payload for long trips but not shorter ones. Only downside to emptying it is that it uses first 10L of water hog to prime system.

 

[ProfJohnL]

...

Provided that none of the limits are exceeded, there's no reason to suggest that lower noseweights provide a "better" margin.

...

Work anything closer to its limit and the margin of safety has been eroded.

 

[Dustydog]

The heavier the static nose load is the more of that safety margin is eroded and there will be more wear and tear on things like the panel work the tow bar is attached to. The effect of vibrations is to multiply the force any mass produces on it support structures, so if you double the nose load it will produce twice the impact loading that any vibrations cause on the assembly.

Surely as in bridge design and aircraft the safety margin is always calculated at the maximum permissible load? Any reference to lower loads may confuse people’s understanding of the design tolerances.
I must admit to not noticing ”vibrations “, . I assume correctly loaded such fsctors should not arise as we are within tolerance? I am sure Hutch wouldn’t say his choppers are at risk being run at their approved maximum performances?

As far as I know there isn't any formal recommendation to work a hitch as close to its maximum allowed. Please feel free to post evidence of it. I know there are a small number of caravanners who swear by it , but they are not the majority.

Experience is a great thing and I for one go with it. I suspect the old lags on here (apologies now) have over many years experimented with nose loads staying within the prescribed limits. My experience says closer to the maximum the better! But I have to ask why would I go lower? What’s the benefit?

Prof’s last post crossed.
In design surely safety margin starts at the maximum tested allowable limit. Not at some lower figure which obviously is more relaxing but not within the design parameters?

 

[RogerL]

Work anything closer to its limit and the margin of safety has been eroded.

Limits are determined by engineers with "adequate" margin of safety - more isn't needed.

By your logic people should be advised to drive at 50 mph in 70 limits!

 

[Lutz]

I would tend to slightly disagree with you. When in the upper limits of the Alko tow hitch of 100 kg. Then when around the 80 kg weight, I can certainly feel a difference in towing my 1645kg Coachman . Depending on how my wife has loaded the fridge I will move the nose weight to be heavier on the way out when on the way home I will lighten the nose load as the van will have a different towing characteristic.
Also the roads will change your towing. As against the length of your outfit. The worst road for me is the A68 from Edinburgh to Otterburn. Totally pitching and yawing, due to the road and the size of my outfit.

Obviously I can also detect the difference between towing with 25kg noseweight instead of at the 80kg limit, but I just wanted to say that although it's undeniably not as good at 25kg it would be wrong to say that it's unmanageable.
As far as noticing a difference in the way the caravan handles in way the fridge is loaded I find that rather far-fetched.
I would agree with you, however, that road conditions do play a big part.

 

[otherclive]

I would tend to slightly disagree with you. When in the upper limits of the Alko tow hitch of 100 kg. Then when around the 80 kg weight, I can certainly feel a difference in towing my 1645kg Coachman . Depending on how my wife has loaded the fridge I will move the nose weight to be heavier on the way out when on the way home I will lighten the nose load as the van will have a different towing characteristic.
Also the roads will change your towing. As against the length of your outfit. The worst road for me is the A68 from Edinburgh to Otterburn. Totally pitching and yawing, due to the road and the size of my outfit.

We travelled a chunck of the A68 down to Otterburn then a few miles south before turning east for Alnwick. Not a caravanning road, but a good drivers road and for bikes too. Sweeping bends and lovely country.

 

[ProfJohnL]

I have revised my post number 28 which seems to have upset a number of contributors.

I never intended to imply the design of the towbar fixings were going to be compromised by using a static nose load at its specified limit, just that less load will cause less wear and tear than more nose load. And by extension you should never exceed the maximum specified static nose load when towing, as the g forces multiplication will increase the effect of any overload, and that does eat into the designed safety margins.

 

[Sam Vimes]

We travelled a chunck of the A68 down to Otterburn then a few miles south before turning east for Alnwick. Not a caravanning road, but a good drivers road and for bikes too. Sweeping bends and lovely country.

Alnwick - one of our first caravan trips. No Sat Nav in those days and the co-pilot wasn't too good at reading maps (still isn't + left and right issues). Should have turned off before Alnwick but instead had to go through the centre - and if you know Alnwick it has a very narrow archway in the centre. Just about cleared it.

 

[trevormonty]

Alnwick - one of our first caravan trips. No Sat Nav in those days and the co-pilot wasn't too good at reading maps (still isn't + left and right issues). Should have turned off before Alnwick but instead had to go through the centre - and if you know Alnwick it has a very narrow archway in the centre. Just about cleared it.

Just about as in didn't or did?.

 

[Sam Vimes]

Just about as in didn't or did?.

Did.