Caravan ball weights

Captain · Veteran Member

Caravan ball weights

outlaw40 · Guru

Wow ! thats overthinking to the next level. your theory could be applied to any part of the caravan or tow vehicle , but thats not how it works . the weights are static weight calculations so when you are stopped. on a lighter note a mental image of a scallie running alongside of you on the highway trying to stick the scales under your wheels just entered my mind .

Olive Oil · Senior Member

Water tank levels would have a major affect on ball weight. Levels are constantly changing on any trip.

Peter_n_Margaret · Guru

The design criteria for a tow bar require that it is capable of a down load of 50% of the maximum tow rating - that is 1.75T for a 3.5T rated tow bar.
It must also withstand that same load in a transverse (sideways) direction and a load of 1.5 times the tow rating (5.25T for a tow rating of 3.5T) in a longitudinal direction.
Cheers,
Peter

iana · Guru

I think Captain old chap you are so right, while the van and towing vehicle are in motion the tow ball weight is for ever changing.

The way I see it, tow ball weight is not an absolute rule, the rule really is center of gravity. And you want the center of gravity to be forward of a line drawn up from the pivot point about the vans wheels. The further forward the G of G is from that vertical line (within reason), the better the stability of the van is. As the C of G moves back to the centerline of the pivot point from the wheels the less stable the van becomes, and if the C of G moves behind, the van is unstable.

Measuring the ball weight is just an indication of where the C of G is. When you go up a hill the C of G will move back, and vis versa when going down hill. Bumps are just little hills.

The maximum ball weight is that number stamped on the tow bar compliance plate, the tow bar has been tested and certified to be able to handle the load and stresses on it for that figure.

Whenarewethere · Guru

The ball weight would be the starting point. As you drive over undulating surfaces the ball weight increases & decreases.

I don't tow but the specs for my car, it has a massive tow ball weight of up to 350kg, 2000kg for on road towing, but only 750kg for off road towing.

Common sense is tie & bolt everything in place like cars on a ship. Take it easy with your rig over challenging surfaces. Go a bit slower & let the tyres down a bit of doing a lot of rough roads.

Half full tanks of water would be a big issue with the water shifting over every bump & braking. Multiple smaller tanks would be better where you can empty 1 tank at a time.

BW · Senior Member

Mine being only a small rig , I would not have anything in the caravan tank and only carried water bottles, usually putting them in places to even the weight. the tank being on the front side of van wheels , added to the weight on the tow ball. Also turfed the great big stove and bought a twin burner took a big slab of weight off.

Craig1 · Guru

" on a lighter note a mental image of a scallie running alongside of you on the highway trying to stick the scales under your wheels just entered my mind "

What a great fate for the older scallies ! Not sure about the new ones

-- Edited by Craig1 on Sunday 21st of April 2019 08:08:18 PM

swamp · Senior Member

Hi
Some ball weight specs are reduced when going offroad by some car makers .

Peter_n_Margaret · Guru

All towing limits are also reduced for the 50mm ball rating of 3.5T if the tug has a GVM of more than 5T (from memory) on a sliding scale.
BW, I assume that you are aware of that?
Cheers,
Peter

yobarr · Guru

Peter_n_Margaret wrote:
All towing limits are also reduced for the 50mm ball rating of 3.5T if the tug has a GVM of more than 5T (from memory) on a sliding scale.
BW, I assume that you are aware of that?
Cheers,
Peter

Hi Peter...As usual,you are correct,this time with your 5 tonne GVM figure.It is a reducing scale,where a vehicle with a GVM of 6500kg is limited to towing a 2972kg ATM trailer if a 50mm ball is used.Cheers.

Noelpolar · Veteran Member

FWIW..... when talking "shock loadings" brought about by causeways or wash aways etc ones is probally operating outside the rating intent of the vehicles standard ratings .By that I mean if ones was towing in a "off road" way....some ratings might be reduced by say 50% for this type of use... so 250kg ball weight max might need to be 125kg max.