working out the 85% rule

[MonkeyHanger]

As i have stated on another thread im after a new tug for my bailey pageant provence which has an MTPLM of 1401kgs and i have been looking at the vauxhall vectra 1.9CDTi in the brochure it has the hatch with a kerbweight of 1459 and a max tow of 1600kgs which of these figures do i go by is it the kerbweight or the tow weight X 85%.

On the other hand i would like the estate vectra 1.9CDTi which has a kerbweight of 1556kgs nearly 100kgs heavier than the hatch but a max tow weight of 1500kgs a 100kgs less than the hatch

im confussed please help me

 

[sparkes]

We all get confused by this when its all new to us

From you figures

saloon is at 96% and the estate is at 90% Both are a little high but if you are experienced and happy with the power then it should not be a problem

 

[Lutz]

Yes, I agree with Steve and would just like to add that one always uses the kerbweight of the towcar to calculate the weight ratio. Bear in mind that the published kerbweights (in your case, the 1459kg quoted for the hatch and 1556kg for the estate) are only guideline figures. The actual kerbweights are invariably higher, so the weight ratio will certainly be more favourable than the 96% and 90% respectively, that Steve worked out for you.

Nevertheless, I would go for the estate, especially as it appears that you prefer it anyway.

 

[WatsonJohnG]

The problem I find with my Nissan X-Trail Columbia 2.2 diesel is finding the correct kerbweight.

Nissan give 1525-1650 for the range but do not specify which is what !!

My friend asked for a Towsure outfit match and it quoted 1525kg for the above vehicle whereas What Car Mag give the same vehicle as 1650kg.

Perhaps Lutz would know a reliable source of accurate figures

 

[WatsonJohnG]

"The 85% Rule" should be regarded as "rule of thumb" or starting point rather than set in concrete RULE

 

[ProfJohnL]

"The 85% Rule" should be regarded as "rule of thumb" or starting point rather than set in concrete RULE

I don't think any one actually quote the 85% as a RULE in this thread, perhaps we are begining to win the education war on this point!

 

[WatsonJohnG]

"The 85% Rule" should be regarded as "rule of thumb" or starting point rather than set in concrete RULE

Hopefully but it was titled "working out the 85% rule"

 

[hughdavies]

The problem with this guideline (not rule) is the way it is calculated. It takes the max weight of the van and the min weight of the car, this does not hapen in real life nobody goes caravaning in an emty car and by deliberatly putting all the heavy stuff in the car the van will not be at its max. My own outfit:- car 1550k van 1700k =110% Actual:- car loaded 1750k van 1550 = 88%.So take some time to work it out, best way is to use a weighbridge.

 

[MonkeyHanger]

Thanks everybody i do know that its not actually a rule as i did a lot of research before buying the caravan as its our first we used to have a tent then a trailer tent before the van itook my time and bought plenty of reading material before getting the van and i know its used as a guide line mainly for safety purposes.

once again thanks

 

[WatsonJohnG]

Hi Andrew I wasn't splitting hairs etc but other people reading the postings can get the wrong idea and often do.

Just felt that it was worth making the point in case....

 

[Steve L]

Look, why not just go with fact.

The car manufacturer will of quoted a max trailer towing capacity for your car,that is what they secify after many hours of deliberation and trials is the maximum safe tow capacity for insurance purposes.

Next, on your VIN plate there is a Max Gross train weight. Normally the largest of all the weights quoted. That is the maximum weight that your car plus caravan and all luggage/occupants can legally weigh on the highway.

Then the tow bar manufacturer will specify the down load (hitch weight) again a maximum for the tow hitch. Also the caravan manufacturer will specify their hitch weight. Use the smaller of the two as your max hitch weight.

Forget all the bull about 85% of the kerb weight giving a safe tow situation.

Go with fact as stated by the manufacturers as when you are stopped and checked by the boys in blue with the men from the ministry in tow, they only want facts not theoretical jargon.

No matter how good a solicitor is in court all the judge will want to know is wether or not the vehicle was towing above the manufacturers spec for either the car or caravan. They are not motoring officinardo's and wouldn't know a wheel nut from a spark plug about cars, all they know is law.

I know from experience of towing a trailer with a 3500Kg truck that, you need a tachograph in the truck but so long as the trailer weighs less than 1000Kgs un-laden you don't need an operators licensce. But 99.9% of the coppers didn't and boy oh boy, did they get stropy when I showed them the letter from the department of transport stating that.

Yep, I was stopped and charged so many times for not having an operators licensce that I had to get official guidance from the Dept of transport.

 

[WatsonJohnG]

Very true Steve.

The 85% guide is not a bad starting point and I was having the same conversation with my friend when the dealers outfit matching came up with 1525kg for the X Trail.(What Car gave 1626kg for a lower spec model)

Nissan say 2000kg max tow weight which is well over the prudent limit on the road.

I have emailed Nissan for the weight of my specific model and they promise a reply within 24 hours.

Mind you they promise to reply to a letter in 4 days but several weeks and 2 letters later I am still awaitng a reply from Customer Care (or should that be careless!)

I remember you making the point about your dealings with the police before.

 

[WatsonJohnG]

Reply from Nissan to Email says that my car kw is between 1525kg and 1650 kg or in other words it was too much trouble to be model specific.

Manufacturing tolerances of 125 kg seem a tad on the high side!

Also reply to letter about mis-fire (now fixed).

Very nicely worded and included voucher.

 

[Lutz]

I think a lot of owners are expecting too much from the car manufacturers in supplying really accurate kerbweight figures for their particular car. Short of weighing each car as it leaves the factory, there is no way one can achieve anything better than about

 

[RogerL]

The "EC Certificate of Conformity" shows the exact kerbweight of the individual vehicle, as built, ie with factory-fit options but not dealer-fit items.

This document is provided in the handbook pack for many vehicles and is available, on demand, for any new vehicle built in the EC or officially imported into the EC (ie excluding used vehicles and personal imports from outside the EC).

Sadly most buyers of new vehicles lose or ignore this useful document.

 

[Val & Frank]

Hello Roger,

Just looking out this EU Certificate of Conformity,but would the boys in blue not work off theUK Registration Certificate ?? On mine it states the following information

note F1 Max permissible mass 2850kg

note G Mass in Service 2265kg

note O Technical Permissible Maximum Towable Mass of The Trailer

note O1 braked 2800kg

note O2 unbraked 750kg

So F1 minus G = 585kg the maximum weight that can be added to the car. Van nose weight is 100kg so 585kg - 100kg nose weight transfered to the car. I can add another 485kg to the car. Seeing as the wife won't let me out on my own, I need to minus her weight 54kg from the 485kg giving me a grand total of 431kg maximum I can carry in the Car !!!

Now is that the way anyone else would work out the Car Loading or am I doing it all wrong ????

ps I have no problem being told I'm wrong, after 38 years of marriage it has happened a lot before !!!!

Val & Frank

 

[WatsonJohnG]

Thanks for your comments Lutz but Nissan quote a difference of 125kg which is the weight difference for all the diesel range.

In answer to my request they just quoted what it says in the brochure for the range which is less than helpfull.

My friend is considering buying an X-Trail at the moment but Nissan could lose the sale because they can't be bothered to give weights for individual models whereas Land Rover etc will give these figures.

I was hoping that there was a source that had the figures on record.

Frank In my Reg document G is left blank !

 

[RogerL]

Frank,

There's no weight information on registration documents for cars although it may be present for motorhomes derived from commercial vehicles.

The police would generally use the weights on the VIN plate but this information may be incomplete (some cars, such as my Vauxhall Astra, have a higher max weight and/or higher rear axle max weight when towing).

Your calculation seems correct but check the notes at the end of the EC Certificate of Conformity to see if there are any variations in max weights when towing.

The Gross Train Weight shown both on the VIN plate and the certificate is an absolute maximum without exceptions.

 

[Val & Frank]

Hi Roger,

I have a Toyota 4x4 LC4 it's an 06 model. I have checked all the documentation that came with the car and, can't find any EU Certificate of Conformity.

What I did find was a plate on the car which states

CAUTION

The Gross Train Weight of this Vehicle Exceeds 3500kg and in Certain Circumstances a Tachograph may be Required when Towing a Trailer.

On the Vin Plate it shows 4 weights

2850kg On the Registration this is F1 Max permissible mass

5650kg F1 + technical permissible max towable mass of trailer

1-1290kg ??

2-1800kg ??

1- and -2 Not sure of

regards

Val & Frank

 

[Val & Frank]

Hi Roger,

I have a Toyota 4x4 LC4 it's an 06 model. I have checked all the documentation that came with the car and, can't find any EU Certificate of Conformity.

What I did find was a plate on the car which states

CAUTION

The Gross Train Weight of this Vehicle Exceeds 3500kg and in Certain Circumstances a Tachograph may be Required when Towing a Trailer.

On the Vin Plate it shows 4 weights

2850kg On the Registration this is F1 Max permissible mass

5650kg F1 + technical permissible max towable mass of trailer

1-1290kg ??

2-1800kg ??

1- and -2 Not sure of

regards

Val & Frank

1- and 2- maybe axle weights 1290kg and 1800kg ?????

Val & Frank

 

[RogerL]

Frank,

Contact the dealer / importer / Toyota GB for the certificate. There may be a charge. You don't "need" the document, it's just useful.

You only need a tachograph if you operate professionally and tow during that time. As a private individual you don't need to be concerned with tachos.

From your VIN plate, 2850 is the max gross weight of your Toyota, 5650 is the max gross train weight, "1" is max front axle load and "2" is max rear axle load. Adding "1" and "2" together may well exceed the max gross weight, as in your case. This is to allow some variation in position of payload, but the max gross weight can't be exceeded.

 

[Lutz]

It is a fact that few car manufacturers weigh each car as it leaves the production line. Hence, even any kerbweight quoted in a certificate of conformity will have a tolerance (I believe it is 5% but I'm not sure, but even that would be 70kg for a 1400kg car).

Where only one figure is quoted in brochures, this is generally for the lightest spec car with the minimum of factory-fitted options. It is often based on the sum of the calculated theorectical weights of each component part as stored in the manufacturer's datbase. I have yet to come across any vehicle which has an actual kerbweight less than the published one. When one takes into account the large number of options that are sometimes available, a range of over 200kg within the same model range is quite reasonable.

 

[WatsonJohnG]

Agreed that over a model range you could expect some variation bur Nissan are quoting to me the published (brochure) range for all the X-Trails for a specific model.

It seems unlikely that "identical" Nissan X-Trail Columbia 2.2 diesels would vary by 125Kg

If a comparative test by What Car shows the base diesel model at 1626kg there must be some source that they have used unless they weighbridged it.

In the film "The French Connection" they weighed a vehicle and comparing the weight to the spec sheet decided that it contained a load of drugs.

From what you say that story line was using a lot of artistic licence.

I thought that if anyone would know of the existence of tables of weights it would be you Lutz.

Anyway thanks for the input.

Does anyone else know of a list of kerbweights other than by magaziness.

 

[Glenn_5132962]

I am a mass properties engineer in the aircraft industry. People in my occupation also work in the shipping, space & automotive sectors. It is our job to collate & predict the weight, cg & inertia of every single component within the car/ship/aircraft. These predictions are totalled to provide an estimated weight. It is this figure(s) that go into all the performance calculations done during design. When the car is put into manufacture they physically check weigh the first few off the production line to verify their predictions.

In the case of a car they will have a basic weight for each model & also the weight of additional factory fitted accessories etc. Nissan will know the weight of your vehicle to the nearest 1kg (its just that they can't be bothered to tell you).

So important is this info in car design that companies go out & buy competitor cars for the sole reason of stripping them & weighing each component.

 

[WatsonJohnG]

I am a mass properties engineer in the aircraft industry. People in my occupation also work in the shipping, space & automotive sectors. It is our job to collate & predict the weight, cg & inertia of every single component within the car/ship/aircraft. These predictions are totalled to provide an estimated weight. It is this figure(s) that go into all the performance calculations done during design. When the car is put into manufacture they physically check weigh the first few off the production line to verify their predictions.

In the case of a car they will have a basic weight for each model & also the weight of additional factory fitted accessories etc. Nissan will know the weight of your vehicle to the nearest 1kg (its just that they can't be bothered to tell you).

So important is this info in car design that companies go out & buy competitor cars for the sole reason of stripping them & weighing each component.

Thanks--Precisely my view