Tow Ball Nose Weights.
Not sure if this the right place to ask question, so the mod may move it. I am aware of 85% ratio and 7% recommendations for towing.
How much tolerance is there in loading thereof ?
Is it an offence to exceed the recommendation of the manufacturer ?
What effect does having no load in the car make, compared with the loading of the rear with awning, camping gear and two, or three, well proportioned rear passengers ?
I assume all is ok, until the rear axle max load is reached.
The reason for asking, is thoughts concerning bike racks. It seems that I can carry more weight on my rear door panel using a strap on rack, because there is no recommended loading of that part of the car, than on a towbar rack.
For a number of obvious reasons, I would prefer a towbar fitting. Lifting onto a roof rack is a realistic option.
Rgds
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If I've read your post right:
Firstly the nose weight will vary with the make of car and van. Cars have differing nose weight capabilities, one of our cars had 75kg, another had 90Kg, what does your car say?
Also the 85% isn't a rule but a guideline based on your experience. 85% is usually set for new towers.
As far as I am aware it is only illegal to exceed the max train weight, again this is in your car handbook. Lutz is the expert on this. You could also call the club's technical helpline
The nose weight in the downward force by the caravan on the tow hitch. The weight you would have to pull if you rtied lifting the van by the hitch. Having more weight in the car boot (awning or people) or a bike rack attached to the rear door (saris type?) will only affect the car's rear suspension and not affect the caravan's force on the hitch. If however your bike rack is on the tow bar then the tow bar will have more weight (force) on it and that will affect the nose weight.
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The 7% noseweight recommendation originated at a time when there were no plated limits and the owner had nothing better to go by. Nowadays, with caravans getting, on the whole, heavier, but the plated towbar limits remaining fairly modest, 7% is often unachievable. For example, my previous car had a 2000kg towload limit but only allowed 80kg noseweight, making 4%. I towed an 1800kg caravan with it and that is still only 4.4%. That being the case, it is always wise to set the noseweight at or just a fraction below the plated limit, whatever it is.
4% is the legal limit that the manufacturer must provide, but there is no minimum value that the owner must set his outfit to, except in Germany where the maximum is at the same time required if one wishes to tow at 100km/h (subject to further constraints which I won't go into here).
The 85% weight ratio recommendation is based on a basically empty car and any additional payload in the car is obviously going to have a favourable effect of reducing the actual weight ratio.
The only legal limits are the plated limits which are:
1. The gross train weight
2. The gross vehicle weight (or MTPLM) of both car and caravan
3. The maximum permitted axle loads of both car and caravan
Exceeding the manufacturer's towload limit or the plated noseweight limit is not, in itself, an offence, unless exceeded by an amount which obviously represents a dangerous condition, but it would jeopardise warranty coverage.
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I would have thought exceeding the towballs limit would be illegal, but knowingly or recklessly doing this could invalidate your insurance.
The idea of carrying bikes on a rack at the back of the car could be problematic as the additional weight could take you over the rear axle limit.
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There are two car loadings to consider regarding tow ball.
First the tow ball is limited by the tow bar plated to show maximum. It is illegal to exceed this.
Secondly the plated maximum rear axle weight of the car. It is illegal to exceed this.
Caravan nose weight is also limited, but that's a separate matter.
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Thanks for your replies, I apologise for my badly worded question, that lead to sound advice, not really relevant to my query ;-) . Having read your replies and reread my question, I can see the error of my ways !
my query revolves around having a towbar mounted bike rack, when loaded would be 10kg over towball recommended 60kg use. Ie 70 kg on a 60kg ball. Not on the caravan A frame, nor whilst towing a caravan, but on the car towball.
I accept that the towball / towbar would be overloaded. However as the car rear seats would be empty, it is unlikely the rear axle would be overloaded.
Mounting the bikes on the towball, would be a safer solution (to my way of thinking) than having the bikes on a webbing on a rear hatch setup you see on cars.
The latter have no weight recommendations other than the Chinese manufacturing instructions which are vague to the extreme.
So I was wondering how much the rules could be bent regarding the towball. If stopped , the rear axle weight could be measured, but unlikely to any where near the max rear axle load.
Rgds
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"I accept that the towball / towbar would be overloaded. However as the car rear seats would be empty, it is unlikely the rear axle would be overloaded."
That's irrelevant, The nose weight has been calculated to allow a safe margin for the stresses that are on the fixings that attach the tow bar to the car. That will vary a lot as you drive and the caravan reacts to the road surface but has been allowed for. It is what it is.
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Perhaps you can point out which law states that it is illegal to exceed the plated towbar limit. I know it would affect manufacturer's liability and warranty coverage, but it is new to me that any law specifically refers to exceeding the towbar's plated limit. Of course, if the load is so excessive that it obviously indicates a dangerous loading condition then that would be covered by general provisions within legislation, but not specifically for the towbar.
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OK still not sure, are you saying you want to mount a bike rack on your tow ball? without a caravan present just a bike rack? If that is correct you have no problem at all. It is the caravan pressing down on the to ball that 'generates' the 60kg When it says the tow ball recommends 60Kg, this is the max or optimum limit it can have or support, the max weight on the tow ball. If you just have a bike rack only (and no caravan) then provided the bike rack and bikes weight less than 60kg you are fine.
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As an aside, I have been looking at my query from another perspective.
There are a number of small cars, that do not have type approval for towbars in the UK, but are type approved to tow trailers in parts of the EU. So you can have a EU (and Austrialiian) registered car, Aygo , VW Up, etc and , believe it or not, some Smart car variants, that can tow up to 500kg, and if visiting the UK, presumably legally towing in this country.
This seems to indicate that cars are manufactured, to take a towing bracket, but not utilised in some countries when certificates are approved.
To add further confusion, reputed towbar manufactuers such as Thule, Brink, make towbars for these cars, but not for towing. These bars are mounted as towbars, but have a tow hitch which is a ball, that a cycle rack can be fitted, but not a trailer.
These bars are freely available from most towbar companies.
So where the legality of mounting a. "" Not "" a tow bar" lies, is open to question. As far as some insurance companies are concerned, there are no problems with insurance, subject to a copy of the towbars, for bikes, manufacturers's certificate being presented.
rgds
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