Kerbweight lower than Max Tow

[otherclive]

Possibly the guide reference to kerb weight needs to be updated to mass in service, as that is basically the figure you should use.

It's poor practice to change a definition because you never know whether someone is talking about kerbweight according to the old definition or according to the new one.
Mass is service isn't a particularly good choice if you want to be really accurate, either. It will nearly always result in a conservative weight ratio figure because mass in service is the minimum that the car can weigh to make it saleable. It wouldn't include any uplevel factory fitted options that the car may have. Bearing in mind that manufacturers are under no obligation to publish kerbweight figures, the closest one will get to kerbweight, as defined in UK legislation, is the actual weight figure that will only be found in the Certificate of Conformity issued with the car. The only difference between that figure and kerbweight is that it allows 75kg for the driver, which kerbweight doesn't, and only a 90% full fuel tank instead of a 100% full one as per the kerbweight definition.

Can’t recall receiving a Certificate of Conformity either with a new car or newish use cars less 9 months old.

 

[Lutz]

Can’t recall receiving a Certificate of Conformity either with a new car or newish use cars less 9 months old.

A Certificate of Conformity must be issued with every vehicle subject to whole vehicle type approval and that has been in effect for a number of years. One would have to produce it, for example, if the vehicle is to be re-registered in a foreign country. Only the CoC contains all the information required to register the vehicle.

 

[ProfJohnL]

Along with so many other factors involved with outfit matching, Kerbweight has had different definitions over time , and its far from easy to establish with any accuracy for any particular vehicle. MTPLM. is now fudged issue as caravans can have two figures which claim to to be MTPLM on the same caravan. If a calculation uses criteria that have considerable uncertainty the outcome of that calculation is going to be doubly uncertain.

I have found no verifiable information on how the UK industries established the 85% guidance figure, and there are some vehicles where applying the 85% guidance figure would actually exceeds the vehicle towing capacity!

The 85% guidance has become caravanning folk law and a tradition which has elevated the perception of its status to be akin to a law!!

There are caravanners who tell us they wouldn't dare exceed the 85% guidance, yet have openly admitted to speeding!

There are some who believe the 85% figure provides some guarantee of safe towing!

Even well respected forum members have fallen victim to its cult, and have started to give it extra credence by implying it was derived from scientific or academic studies. Please if anyone has any evidence to support that conjecture please let us know.

Although the 85% figure is difficult to support logically, it does stem from the sensible approach of trying to keep the mass of any towed trailer as small as is reasonably possible.

Legally the only limits that must be adhered to in regards towing weights, are the Gross Vehicle Wight ( MAM), the cars Gross Train Weight,(Combined MAM) and the Axle Loads and the maximum nose load. But remember just being legal is no guarantee of safety. Its entirely possible for a vehicle to be fully compliant regards weights, but the load it is carrying is unsafe.

EDIT CORRECTION The Gross Train Weight is NOT the same thing as the Combined MAM

 

[otherclive]

Can’t recall receiving a Certificate of Conformity either with a new car or newish use cars less 9 months old.

A Certificate of Conformity must be issued with every vehicle subject to whole vehicle type approval and that has been in effect for a number of years. One would have to produce it, for example, if the vehicle is to be re-registered in a foreign country. Only the CoC contains all the information required to register the vehicle.

Be that as it may I have never had one with any vehicle. I have received the Owners Manuals, Service Schedules and V5 but no Certifcate of Confirmity. Although I do have one for the caravan.

 

[otherclive]

Taken from Honda UK website. So not all cars are provided with one, but one can be obtained on presentation of the V5 /VIN. My last four cars going back to 2004 have not been provided with a COC. Kia, Volvo,Subaru, Skoda nor has our Nissan either. So it doesn’t seem to be an automatic provision although no doubt if I wished to obtain a COC it can be arranged.

CERTIFICATE OF CONFORMITY
What's a Certificate of Conformity?

A Certificate of Conformity (COC) is granted for a car when it meets a minimum set of regulatory, technical and safety requirements.

You’ll need this certificate if you want to export your car overseas.

If your car was registered after 2001 and was originally registered for the UK market you should be able to apply using your VIN. This can be posted directly to you, free of charge.

Please note if your vehicle has already been issued with a Certificate of Conformity, in order to receive a duplicate certificate there will be a charge of £75 to cover the administrative costs. If you are unsure if the Certificate is a duplicate or not, please request the Certificate and we will be in touch with you if payment is required.

How to get one

To get your COC, email us at certificateofconformity@honda-eu.com including your full VIN number and your address details.

You can expect to receive your certificate within 28 days.

Suzuki UK do not issue them with vehicles but they too have to be applied for from Suzuki. So it doesn’t seem to be an automatic deliverable in UK.

 

[Lutz]

Kerbweight has had different definitions over time , and its far from easy to establish with any accuracy for any particular vehicle.

I am not aware of the legal definition of kerbweight, or kerbside weight as it is officially called, ever having been changed.

Legally the only limits that must be adhered to in regards towing weights, are the Gross Vehicle Wight ( MAM), the cars Gross Train Weight,(Combined MAM) and the Axle Loads and the maximum nose load.

Which piece of legislation makes exceeding the plated noseweight illegal (unless it's so high that it obviously constitutes a danger to other road users, but then the max. rear axle load of the towcar will probably be exceeded anyway)? As far as I know exceeding the noseweight limit would only jeopardise warranty coverage and relieve the manufacturer of product liability.

If I may be a little pedantic here, gross train weight and combined MAM are not one and the same. Gross train weight is the sum of all axle loads. Combined MAM is the sum of the gross vehicle weight of the towcar and the MTPLM of the trailer. Combined MAM is only relevant for Category B driving licence restrictions.

Be that as it may I have never had one with any vehicle. I have received the Owners Manuals, Service Schedules and V5 but no Certifcate of Confirmity. Although I do have one for the caravan.

Is the one that you have for the caravan a type approval certificate of conformity or is it the Certificate of Conformity that the NCC issues to document that certain industry standards are met?

 

[ProfJohnL]

Lutz is correct. I have made a mistake concerning the Gross Train Weight that is NOT the same as Combined MAM.

 

[ProfJohnL]

I delayed my responses to the points that Lutz raised against my posting.

The issue of Kerbweight (Kerb weight ). Its definition has been diluted over time depending on where you read it, and in the eyes of the public it certainly does raise questions of consistency of meaning. Given the context of my posting which was to point out the variations of meaning that have been widely expressed or understood, the value of using it as a criteria for assessing towing ratio's is questionable.

The issue of the S value as a legal limit, is a bit of a grey area. I do recall reading something about being used as legal limit in some document several years ago, but I cannot find the reference at present. Howver the authorities require motor manufacturers to set certain well defined criteria for GVW GTW and axle loads for the purpose of setting criteria for assessing compliance with weight legislation. The EU in its wisdom also required road vehicles and trailer manufacturers to set the S values for couplings, and whilst its not clear if prosecutions have ever taken place for excess caravan nose load over the tow vehicles S value have arisen, the authorities can deem a load in excess of a manufacturers set limit, to be unsafe, so prosecution could occur on that basis. It would seem a bit ridiculous for the authorities to require a criteria to be defined and not have some form of legislation to sanction excesses.

 

[Lutz]

Requiring the manufacturers to specify an 'S' value was, as far as I know, only a means to commit the manufacturers to document a limit up to which they would accept product liability. In Germany it is a requirement to set the noseweight at the maximum allowable level if you wish to tow at 100km/h (among other technical requirements) but, to my knowledge, only there does the S value have any legal significance to the end user.