Noseweights (again?) !!!

[KeithJ]

I have just downsized from a Bailey Pageant Burgundy S6 to a Lunar Quasar 464.
The Bailey was able to take gas cylinders, spare wheel and various other things in tha gas locker with never a problem with the nose weight. In fact I often wondered why others apparently had such difficulty.
The Lunar is a different story. I have one Calor light (nearly full) and one Camping Gaz 907 (nearly empty), and very little else in the locker and the nose weight is 100kg! (This represents 8% of the MPTLM of the 'van and is 10kg above the max for the car.) This is with the van loaded except for clothes, bedding and food. I will load some clothes and bedding at the back of the van, but since the fridge and wardrobe are slightly forward of the axle I don't expect this to improve the situation.
Looking at the layout of the van, two things appear to contribute to the problem - neither of which I can do anything about.
1. The makers have sighted the hot water heater right at the very front (this weights 7kg empty)
2. The mover is in front of the axle (this weighs 35kg).
I have accepted I will have to carry quite a few items in the car boot - this is no problem, but these items have not been included in the weights I have quoted.
I would appreciate any helpful suggestions/advice.

 

[ProfJohnL]

Hello Keith,

In relation to the mover, whilst it may weigh 35Kg, but its so relatievly close to the axle, the additional nose load it creates is most likely to be less than 4Kg,and probably nearer 2Kg.

Sling your spare wheel under the rear of the caravan, don't take spare gas cylinders, it all helps.

I fully appreciate it does not help but its inflence is far less than any item located nearer the hitch. The caravan designers could do more to help in these situations,but that is a matter for you to take up with them.

 

[Surfer]

What did you use to measure nsoeweight?

 

[Mel]

We had exactly the same problem with our first Swift (noseweight c120kg when "empty") but found that putting something heavy just behind the axle balanced it up nicely. The full size awning with steel poles generally did the job, but if we weren't taking this then the Cadac did just as well. Obviously you have to watch the overall payload but we generally travelled quite frugally. Avoid the temptation to load all the heavy stuff right at the back of the van; it will sort the noseweight but at the cost of stability.
mel

 

[ProfJohnL]

Hello Mel,

The advice not load at the end is good sense, but sometimes it may be necessary, and it wont always result in a stability problem. Its a questions of degree, and for that reason it is not necesarilly a no-no.

Some caravans are offered with different layouts; where the only difference is an end bathroom o bedrom etc. Each of these have differnt end loads due to their construction, adn thecan all tow quite happily.

So no end loading is another of the caravanning traditions that have been perpetuated by continual dogmatic repretition with stories of foreboding, yet in practice there is more latitude than most give it credit for.

 

[JTQ]

In relation to the mover, whilst it may weigh 35Kg, but its so relatievly close to the axle, the additional nose load it creates is most likely to be less than 4Kg,and probably nearer 2Kg.

With respect Professor but surely that statement can only have been made as a casually considered assumption?
The underlying facts I suggest dictate that the effect of relocating the mover will result in far bigger benefits to the OP and others than what you are stating.

10 years ago I needed to do the arithmetic and found I benefited by nearly 8 kgs and that was with a long van where such benefits are smaller than with shorter vans.

Your statement has prompted me to recalculate things. My mover is a Powrtouch HD.

Turning moment of the mover about the caravan’s wheel axle equals: -

Estimated mover weight X estimated position of mover relative to the axle.

38 kgs x 49 cm = 1862 kgcm

[This figure I suggest is likely to be “similar” whatever the van mover combination as wheel size, mover’s weight and where the mover centre of gravity would be are fairly “similar”. Note “similar” not precisely the same]

The towball reaction to balance this turning moment is directly related to the distance from the axle to the towball. The reaction being a downward force where the mover is in front of the axle and negative where it is behind the axle means the overall difference in repositioning the mover from forward to aft is twice the reaction.

With my van an extremely long “A” framed, 7.9metre German van that axle to towball distance is 478cm.

So the difference in towball force in choosing an aft rather than forward position for the mover is :

1862 kgcm divided by 478 cm multiplied by 2 = 7.79 kg

My van is abnormally long and so the benefits in placing the mover aft of the axle will be less than for many.

If we assume a metre odd shorter van with this axle to ball distance half a metre less than mine the figures become:

1862 / (478-50) X 2 = 8.7 kg

 

[KeithJ]

Thanks all
Prof John - I have removed the spare gas cylinder (nearly empty Camping Gaz). That will save a couple of kilos, but the spare wheel is already at the back on an Alko carrier. When Itravel abroad I usually take a full and an empty Camping Gaz and no Calor, so that will also help.
Surfer - I initially weighed the nose on one of those telescopic measures - only calibrated to 95kg, but it went off the scale. So I took it to a weighbridge and weighed the whole van first (1200kg) then just put the nose wheel on (100kg). I know this is not the best way, but the operator had lorries waiting and wanted to get rid of me ASAP! He wasn't at all chatty!
Mel - The MTPLM is 1240kg and I already have 1200, so putting the awning in the van is a non starter. I have to put it in the car.
It seems that re-siting the mover behind the axle would help quite a lot, but this would involve removing the spare wheel carrier and then where would I put the spare wheel? On the Bailey I did this and the spare wheel went in the gas locker but then the extra weight at the front needs to be viewed against resiting the mover to the back!!! On the Bailey the noseweight was not a problem so it worked well. I am not so sure it would with the Lunar, and it would be expensive to ask the dealer to re-site the mover.
I will keep chipping away to see what else I can move, but it is not easy.
One more thought - I wonder what increments the weighbridge works to - they seem to be very round figres.

 

[JTQ]

It seems that re-siting the mover behind the axle would help quite a lot, but this would involve removing the spare wheel carrier and then where would I put the spare wheel?

Keith, some of the mover makers do a kit to relocated the spare wheel a little further aft than normal; which give additional noseweight savings.
I saw a van with brackets to do this but that was a bit of a "pigs breakfast" and looked if it could have been a home-made effort.

 

[Sproket]

It seems that re-siting the mover behind the axle would help quite a lot, but this would involve removing the spare wheel carrier and then where would I put the spare wheel?

Keith, some of the mover makers do a kit to relocated the spare wheel a little further aft than normal; which give additional noseweight savings.
I saw a van with brackets to do this but that was a bit of a "pigs breakfast" and looked if it could have been a home-made effort.

Could this be the one ?

ALKO Spare Wheel Carrier Moving System (WEB/AWC)

When the installation of the Powrtouch is required to be behind the caravan wheels or fitting the All Wheel Drive Powrtouch (Model 6) the under slung ALKO spare carrier will interfere with the Powrtouch Mover. We can supply and fit a Powrwheel Limited designed kit that allows the ALKO spare wheel carrier to be re-sited. This requires no drilling of the ALKO Chassis. The kit can be also be fitted to BPW chassis but the BPW spare wheel carrier will have to be replaced with and ALKO carrier.

 

[ProfJohnL]

Hello JTQ

Yes you are correct, I did make a failry quick assumtion, I estimated that the ratio between the distance from the movers CoG to the axle was approx 1 tenth of the hitch to axle so the relative weights would also share a 10:1 ratio. I was conscious that it depends on the geometry of the caravan design, but as a guide it seemed reasonable.

Thus on the basis of 10:1 a mover weighs about 35Kg, the net effect at the tow hitch would be about 3.5Kg. To allow for some variations in design I gave some variability to the estimate.

My estimate actually concurs with reasonably well with your own specific calculation.

So the addition of a mover will have that degree of effect on the nose weight. The nose weight can increase of decrease by the same amount depending on where the mover is fitted:

If it's in front of the axle then the nose weight will increase, and if it's aft of the axle the nose weight will decrease.

It shows the principle very clearly that heavy items near the axle will have less of an effect on the nose weight. By the same token it also shows how lighter objects can have a more significant effect on the nose weight if loacted near the extremes of the caravan.

It would certainly help the OP if the mover could be relocated behind the axle, though as he points out it may compromise the spare wheel. Perhaps Sproket's pointers to the spare wheel adapter may help.

On many occasions I have carried the spare wheel on the floor inside the caravan It makes a good ballast item for helping to trim the nose weight. I have often found placing it in the door way is sufficient. A relative does the same but he has made a box which it sits in, and then he uses the box as door step.- handy if you need to change the wheel, handy for when you get on site, and a good sized step that doesn't sink into soft ground.

Alternatively the wheel could be carried in the car. thus saving payload in the caravan.

 

[ProfJohnL]

Temporary edit

 

[otherclive]

I too am now in the habit of carrying the spare wheel in the van. It locates securely between the cooker and Truma heater. I started this when abroad to avoid having to extract the wheel into the traffic stream, but now do it as a matter of course. When on site I use a security chain to secure it to the chassis. If I should get a puncture it makes it so much easier to jack up the van remove the defective wheel and fit the spare given that even a puncture on an A or B road could be in a spot where it's not possible to pulll the spare wheel carrier out.