85% rule
- Thread starter will2
- Start date
First of all, to make it quite clear, this is not a rule but only a recommendation.
The way it is calculated is as follows:
The max. laden weight of the caravan (its MTPLM) should ideally not be more than 85% of the kerbweight of the towcar. You can usually find details of the MTPLM and a rough indication of the kerbweight in the respective owner's handbook and/or brochures.
However, be careful, you must also stay within the maximum permissible towload that the car manufacturer specifies. In a few cases, this is less than 85% of its kerbweight, in which case it is the lower of the two figures that counts.
Legally and insurancewise, it is always the manufacturer's specification that limits what you may tow. The spec may allow you to go over 85% but when towing something big and boxy like a caravan, even an experienced caravanner should never go over 100%, even if the manufacturer's spec permits a higher towload. Towloads over 100%, where permitted, are only appropriate for low loader trailers.
The way it is calculated is as follows:
The max. laden weight of the caravan (its MTPLM) should ideally not be more than 85% of the kerbweight of the towcar. You can usually find details of the MTPLM and a rough indication of the kerbweight in the respective owner's handbook and/or brochures.
However, be careful, you must also stay within the maximum permissible towload that the car manufacturer specifies. In a few cases, this is less than 85% of its kerbweight, in which case it is the lower of the two figures that counts.
Legally and insurancewise, it is always the manufacturer's specification that limits what you may tow. The spec may allow you to go over 85% but when towing something big and boxy like a caravan, even an experienced caravanner should never go over 100%, even if the manufacturer's spec permits a higher towload. Towloads over 100%, where permitted, are only appropriate for low loader trailers.
Hello Will,
The 85% figure is not a rule it is only a guideline suggested by the caravan fraternity - for towing caravans - it has no basis in law and is not suggested for other types of trailers.
In simple terms it is the actual Mass (weight) of the caravan as a percentage of the kerb mass(weight)of the tow car.
Hopefully you will understand that it makes sense to keep the mass of the caravan as low as possible, to help towards and easy to handle outfit, and 85% is a reasonable target, though I must add a cautionary note: simply adhering to 85% does not guarantee a good outfit - that depends an many other variables, the actual vehicle, how the caravan is packed for weight distribution, Condition of tyres suspension of both car and caravan, and most importantly driving habits.
There are certain legal limits that must comply with. I suggest you view the web pages of the NTTA:
http://www.ntta.co.uk/faq/default.htm
although my answer may seem daunting, by taking the points one step at a time there is every likelihood that you will find you can achieve all that is necessary to have a safe and enjoyable experience
The 85% figure is not a rule it is only a guideline suggested by the caravan fraternity - for towing caravans - it has no basis in law and is not suggested for other types of trailers.
In simple terms it is the actual Mass (weight) of the caravan as a percentage of the kerb mass(weight)of the tow car.
Hopefully you will understand that it makes sense to keep the mass of the caravan as low as possible, to help towards and easy to handle outfit, and 85% is a reasonable target, though I must add a cautionary note: simply adhering to 85% does not guarantee a good outfit - that depends an many other variables, the actual vehicle, how the caravan is packed for weight distribution, Condition of tyres suspension of both car and caravan, and most importantly driving habits.
There are certain legal limits that must comply with. I suggest you view the web pages of the NTTA:
http://www.ntta.co.uk/faq/default.htm
although my answer may seem daunting, by taking the points one step at a time there is every likelihood that you will find you can achieve all that is necessary to have a safe and enjoyable experience
Quote, "Towloads over 100%, where permitted, are only appropriate for low loader trailers" unquote, this is NOT true whatsoever. If you view the pages of NTTA as John L suggests this will confirm that your statement is 100% incorrect!
Robin, my statement does NOT conflict with the information given by the NTTA if you passed your driving test before the 1st January 1997 or if you have subsequently obtained a category B&E licence.
Lutz
I agree with what you say but the towed weight in the formula is not the MTPLM it is the actual towed weight (which hopefully should be less than the MTPLM) so if you can keep the additional weight in the van low you will achieve a lower ratio.
For a bit of extra security it does not hurt to use the MTPLM though.
I agree with what you say but the towed weight in the formula is not the MTPLM it is the actual towed weight (which hopefully should be less than the MTPLM) so if you can keep the additional weight in the van low you will achieve a lower ratio.
For a bit of extra security it does not hurt to use the MTPLM though.
Lutz, Your original posting, considering that will is quite new to caravanning, I don't think was explicit enough. However, you have now clarified the fine line between before and after 01st January 1997 and added that B+E is a absolute legal necessity to exceed trailer / combined vehicle weights. It is surprising the amount of people that are oblivious to this fact. I actually mentioned this to a particular caravan site owner this year and he said that he had never heard of any changes with regard to B+E and thought that everyone got it on their licence automatically!
To my knowledge, it is, and always has been, standard practice to use the MTPLM to calculate weight ratios as this represents the worst possible case. It is also the basis for one of the criteria in determining whether a category B licence is adequate or a B&E is required.
Likewise, one does not use the actual weight of the car when towing but its kerbweight. Obviously, actual weight ratios will be much lower.
It would not be logical to use the actual weight of the caravan and compare that with the kerbweight of the car. A ratio calculated on that basis is rather meaningless as it cannot be compared with any other published data.
Likewise, one does not use the actual weight of the car when towing but its kerbweight. Obviously, actual weight ratios will be much lower.
It would not be logical to use the actual weight of the caravan and compare that with the kerbweight of the car. A ratio calculated on that basis is rather meaningless as it cannot be compared with any other published data.
Lutz
I can not cut and paste this, it is from the CC site
http://www.caravanclub.co.uk/NR/rdonlyres/801876BF-A519-46FF-BC4F-F2DF284BD52C/0/TopTwentyCaravanningQuestionsAnswered.pdf
Another lovely TLA - ALW = Actual Laden Weight as opposed to BLW = Bin Laden Weight = not very much at the moment apparently!
I only know this because I had to work it out as I knew I was over 85% when I used the criteria you are using.
I can not cut and paste this, it is from the CC site
http://www.caravanclub.co.uk/NR/rdonlyres/801876BF-A519-46FF-BC4F-F2DF284BD52C/0/TopTwentyCaravanningQuestionsAnswered.pdf
Another lovely TLA - ALW = Actual Laden Weight as opposed to BLW = Bin Laden Weight = not very much at the moment apparently!
I only know this because I had to work it out as I knew I was over 85% when I used the criteria you are using.
I don't know if anyone has ever done any experimenting to determine the effects of towing above or below 85% with any given outfit. I think it's a figure which has been pulled out of the air. What I can tell you is that I tow a 2t 'van with a Grand Cherokee and it is as solid as a rock, even in unexpected situations. I recently had the displeasure of towing my 'van with a LR Discovery though, and it was the most frightening tow I've ever made, so I don't think weight ratio is the whole story by a long way.
Garry, I read the page from the CC site that you refer to and they do, indeed, talk about actual laden weight of the caravan but, for the following reasons, it doesn't make sense to me:-
a) the figures wouldn't be comparable with other published data, and
b) if one is going to use actual weight of the caravan, it would only be logical to use the actual weight of the car, too, and
c) the law regarding licence requirements does say that, for a category B licence, the MAM (maximum allowable mass - not the actual weight) of the trailer may not exceed the unladen mass of the towing vehicle.
a) the figures wouldn't be comparable with other published data, and
b) if one is going to use actual weight of the caravan, it would only be logical to use the actual weight of the car, too, and
c) the law regarding licence requirements does say that, for a category B licence, the MAM (maximum allowable mass - not the actual weight) of the trailer may not exceed the unladen mass of the towing vehicle.
I'll firstly endorse what John and Lutz have said. the 85% is a mythical guide to a supposed safe tow for a novice tower.
You realy don't have to worry about that. You can tow right upto the max tow capacity of your car without major worries so long as the caravan is loaded with the heavy items low down and over the axle, and the nose weight is correct. Usually the nose weight (weight placed on the tow hitch by the caravan when coupled to the car) is about 75Kgs, but this is defined by what is stated by the manufacturer of the caravan and what your car manufacturer has defined. You have to use the lower figure of the two as your hitch weight.
A simple set of bathroom scales with a piece of 20mm plywood placed on top for strength and then zero'd, and placed under the jockey wheel will allow you to measure the nose weight easily without expense. (
You realy don't have to worry about that. You can tow right upto the max tow capacity of your car without major worries so long as the caravan is loaded with the heavy items low down and over the axle, and the nose weight is correct. Usually the nose weight (weight placed on the tow hitch by the caravan when coupled to the car) is about 75Kgs, but this is defined by what is stated by the manufacturer of the caravan and what your car manufacturer has defined. You have to use the lower figure of the two as your hitch weight.
A simple set of bathroom scales with a piece of 20mm plywood placed on top for strength and then zero'd, and placed under the jockey wheel will allow you to measure the nose weight easily without expense. (
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