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Towing Myths

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1 hour ago, matelodave said:

An increase in Mass in Service doesn't necessarily infer a higher GVW or GTW in theory it reduces your payload or even the allowable mass of the trailer

 

That’s sort of my point, the ‘weight’ of the vehicle has increased but it doesn’t make the blindest but if difference to the balance/ capability to tow the same caravan.

 

Its highly unlikely the GTW or GVW is ever increased if the car is actually heavier, it just reduces the available payload.

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3 hours ago, Black Grouse said:

 

Don't you think the weights are stored in a computer - simple to make it very specific to the unique vehicle.

 

When I ordered a top-trim Astra with several major options like automatic and sunroof, the figure on the V5C obviously included them as it was way more than standard cars.

 

No. Options like a sunroof or even a factory-fitted towbar are not necessary to make the car saleable (which is the basis of the definition of Mass in Service) so they won't be included in the Mass in Service. Automatic may be included because it is type approval relevant so it counts as another model.

 

Edited by Lutz

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I got caught out, checked on internet and caravan dealers info as to what car could tow, said 1500 so caravan 1450 laden so within the law, then found log book and rated 1350 seems year before was 1500 and year after 1500 but one we had was not, so car changed.

 

Other car rated towing capacity is zero, we tend to call it a Renault Kangoo however it was modified by a firm called GoWing and that is the manufacturers name on log book.  

 

Alterations before the vehicle is registered are clearly taken into consideration, as to something like a Landrover  where it can have between 1 and 12 seats the weight can alter so much it must be taken as in the trim supplied. The Landrover is saleable with no body, as many vehicles sold as chassis cabs.

 

There is nothing to stop me removing seats and replacing windows with light panels, glass is heavy so the weight of a car derived van is very different to the car, often much lighter.

 

It seems year after our car was bought the vehicle had 7 seats, as a result it was heavier so towing capacity went up, I am sure if you wanted you could apply to have a vehicle reassessed, if some thing is permanently fitted or removed, this is exactly what happens when altered to carry the disabled.    

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Surely the towing limit of a vehicle, which usually, but not always, matches the GTW minus GVW is the governing factor and is set based on a number of factors, not just the weight of the vehicle. There's structural strength, power and power delivery and handling, transmission capability, engine cooling and braking capability that can all be involved in setting such a limit. The various percentages of kerbweight that are recommended for caravanners are arrived at rather less scientifically but are based on a healthy 'safety first' principle with good margins, but aren't  technically provable in the same way.

 

By that I mean pulling a caravan that's over the towcar's towing limit when the limit was set because of a transmission made of plasticine will result in transmission failure. An inexperienced tower running a rig at 95% of the car's kerbweight won't cause mechanical failure and maybe 99.9% of the time will be perfectly fine BUT if things go wrong in poor conditions the driver may not have developed the instincts/skills to control the problem and potentially a heavier ratio can make those problems worse. So it's likely that most inexperienced towers will never face a challenging situation as described but it's surely always best to have a margin on such potentially dangerous situations?

 

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The towload limit specified by the manufacturer is completely independent of the MIRO or kerbweight or actual weight, so we shouldn't get involved in discussing the relevant effect of any factory fitted options on allowable towloads.

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9 hours ago, Lutz said:

 

No. Options like a sunroof or even a factory-fitted towbar are not necessary to make the car saleable (which is the basis of the definition of Mass in Service) so they won't be included in the Mass in Service. Automatic may be included because it is type approval relevant so it counts as another model.

 

 

Vauxhall were wrong then in the past!

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40 minutes ago, Black Grouse said:

 

Vauxhall were wrong then in the past!

 

What do you mean when you say they were wrong? I didn't know that Mass in Service figures were ever published for all model variants.

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19 minutes ago, Lutz said:

 

What do you mean when you say they were wrong? I didn't know that Mass in Service figures were ever published for all model variants.

 

Vauxhall used to publish "kerbweight" in their sales brochure and owners handbook by body type, engine, transmission and trim, the handbook also listing the weights of factory-fit options - the Certificate of Conformity and V5C both displayed "Mass In Service" equal to the addition of factory-fit options to the specific model's kerbweight. In Vauxhall's case, kerbweight + options was numerically equal to Mass In Service.

 

At least 4 of the Vauxhalls I had, complied with the concept of exact figures for Mass In Service - so did my Hyundai Santa Fe - but my VW Touareg didn't, the V5C Mass In Service being the same as shown for the base model in the brochure, ie without the extra weight of sunroof, parking heater or factory-fit towbar.

Edited by Black Grouse

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10 hours ago, Lutz said:

 

No. Options like a sunroof or even a factory-fitted towbar are not necessary to make the car saleable (which is the basis of the definition of Mass in Service) so they won't be included in the Mass in Service. Automatic may be included because it is type approval relevant so it counts as another model.

 

 

If Mass in Service is the weight of the vehicle as it leaves the factory, how can sunroofs towbars and other factory fitted options not be included?

 

Interestingly when you Google "Mass in Service" there is no definition!

 

However if you go to the Gov website it does mention Down Plating

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12 minutes ago, Grandpa Steve said:

 

If Mass in Service is the weight of the vehicle as it leaves the factory, how can sunroofs towbars and other factory fitted options not be included?

 

Interestingly when you Google "Mass in Service" there is no definition!

 

However if you go to the Gov website it does mention Down Plating

 

Here are a few definitions, including that of Mass in Running Order (which is the same as Mass in Service on the V5c), as laid down in Article 2 of EU Directive 1230/2012/EC:

 

(4) ‘mass in running order’ means

(a) in the case of a motor vehicle: the mass of the vehicle, with its fuel tank(s) filled to at least 90 % of its or their capacity/ies, including the mass of the driver, of the fuel and liquids, fitted with the standard equipment in accordance with the manufacturer’s specifications and, when they are fitted, the mass of the bodywork, the cabin, the coupling and the spare wheel(s) as well as the tools;

(b) in the case of a trailer: the mass of the vehicle including the fuel and liquids, fitted with the standard equipment in accordance with the manufacturer’s specifications, and, when they are fitted, the mass of the bodywork, additional coupling(s), the spare wheel(s) and the tools;

 

(5) ‘mass of the optional equipment’ means the mass of the equipment which may be fitted to the vehicle in addition to the standard equipment, in accordance with the manufacturer’s specifications;

 

(6) ‘actual mass of the vehicle’ means the mass in running order plus the mass of the optional equipment fitted to an individual vehicle;

 

It becomes obvious from reading the above that things like sunroofs and factory fitted towbars are not considered as 'standard equipment'. Only the 'actual mass of the vehicle' (Item 6) will include optional extras.

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9 minutes ago, Lutz said:

 

Here are a few definitions, including that of Mass in Running Order (which is the same as Mass in Service on the V5c), as laid down in Article 2 of EU Directive 1230/2012/EC:

 

(4) ‘mass in running order’ means

(a) in the case of a motor vehicle: the mass of the vehicle, with its fuel tank(s) filled to at least 90 % of its or their capacity/ies, including the mass of the driver, of the fuel and liquids, fitted with the standard equipment in accordance with the manufacturer’s specifications and, when they are fitted, the mass of the bodywork, the cabin, the coupling and the spare wheel(s) as well as the tools;

 

(5) ‘mass of the optional equipment’ means the mass of the equipment which may be fitted to the vehicle in addition to the standard equipment, in accordance with the manufacturer’s specifications;

 

(6) ‘actual mass of the vehicle’ means the mass in running order plus the mass of the optional equipment fitted to an individual vehicle;

 

It becomes obvious from reading the above that things like sunroofs and factory fitted towbars are not considered as 'standard equipment'. Only the 'actual mass of the vehicle' (Item 6) will include optional extras.

 

Having read the Directive I cannot see anything that says the Mass in Running Order is the same as Mass in Service!

How can Mass in Running Order be the same as Mass in Service when the Mass in Service is the weight of the car as it leaves the factory, and the Mass in Running Order includes only standard equipment, the driver and 90% of its fluids.

 

As said if you Google either term there is no explanation.

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17 hours ago, Grandpa Steve said:

 

How does that apply to a car where the towbar is specified as a factory fit, thinking about the BMW's & Mercs where the rear cross member is replaced on the production line with a different one that carries the electrically operated tow hitch? 

Good question as the same happens when you have a towbar fitted onto the Jeep.

2 hours ago, Lutz said:

The towload limit specified by the manufacturer is completely independent of the MIRO or kerbweight or actual weight, so we shouldn't get involved in discussing the relevant effect of any factory fitted options on allowable towloads.

Isn't the thread about towing myths and specifically the 85% ratio suggested by the CC.   Altering the MIS by adding a towbar would allow a newbie to stay within the 85% ratio guideline, but with a heavier caravan.   It probably would also affect insurance where they have a clause regarding the kerbweight as the new weight would alter the MIS weight making that clause unenforceable.

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1 hour ago, Durbanite said:

Isn't the thread about towing myths and specifically the 85% ratio suggested by the CC.   Altering the MIS by adding a towbar would allow a newbie to stay within the 85% ratio guideline, but with a heavier caravan.   It probably would also affect insurance where they have a clause regarding the kerbweight as the new weight would alter the MIS weight making that clause unenforceable.

 

A towbar plus all the accompanying electrics is unlikely to weigh more than about 40kg and that's not going to affect the weight ratio by anything worth talking about.

Unlike Mass in Service, kerbweight would be increased by adding the towbar (and any other factory-fitted options), but where does one find the kerbweight documented anywhere? You won't.

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1 hour ago, Durbanite said:

 

Isn't the thread about towing myths and specifically the 85% ratio suggested by the CC.   Altering the MIS by adding a towbar would allow a newbie to stay within the 85% ratio guideline, but with a heavier caravan.   It probably would also affect insurance where they have a clause regarding the kerbweight as the new weight would alter the MIS weight making that clause unenforceable.

Yes, that's how it started. however, it's a little like arguing how many angels fit on the head of a pin! There are so many assumptions and variables, and even then it can only ever be a very rough rule of thumb, as to make the question and any subsequent answer meaningless.

If, and it's a big "if" towing ratio is of any real relevance, in its own right,  from the perspective of stability and safety, then the ratio should be calculated on the basis of actual laden weights. the differences in methods of calculation and definition between MIRO, kerbweight, unladen weight or weight at the kerbside all pale into insignificance compared to the importance of GTW and axle loadings!

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With some vehicles there is the option of adding a second 12v battery which if added to the weight of the towbar etc could increase the kerbweight by up to 50kg again throwing the 85% guideline out the window.

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2 hours ago, Grandpa Steve said:

 

Having read the Directive I cannot see anything that says the Mass in Running Order is the same as Mass in Service!

How can Mass in Running Order be the same as Mass in Service when the Mass in Service is the weight of the car as it leaves the factory, and the Mass in Running Order includes only standard equipment, the driver and 90% of its fluids.

 

As said if you Google either term there is no explanation.

 

I raised the issue with the DfT a couple of years ago and I was told unofficially that someone in their infinite wisdom decided to call it Mass in Service in the V5c, but actually when the vehicle registration book is issued, they use the Mass in Running Order figure that the manufacturer documents in the Certificate of Conformity because there is nothing else that is documented to go by.

1 minute ago, Durbanite said:

With some vehicles there is the option of adding a second 12v battery which if added to the weight of the towbar etc could increase the kerbweight by up to 50kg again throwing the 85% guideline out the window.

 

Even 50kg is not going to make or break an outfit. If the weight ratio goes up to 86 or even 87%, so what? Nobody is going to detect any difference in the way the same outfit handles.

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Interesting - Gov website says:-

 

Unladen weight

The unladen weight of any vehicle is the weight of the vehicle when it’s not carrying any passengers, goods or other items.

It includes the body and all parts normally used with the vehicle or trailer when it’s used on a road.

 

It doesn’t include the weight of:

fuel

batteries in an electric vehicle - unless it’s a mobility scooter or powered wheelchair

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This is the definition of unladen weight, as laid down in Part 1 of The Road Vehicles (Construction and Use) Regulations 1986:

 

Unladen weight

 

the weight of a vehicle or trailer inclusive of the body and all parts (the heavier being taken where alternative bodies or parts are used) which are necessary to or ordinarily used with the vehicle or trailer when working on a road, but exclusive of the weight of water, fuel or accumulators used for the purpose of the supply of power for the propulsion of the vehicle or, as the case may be, of any vehicle by which the trailer is drawn, and of loose tools and loose equipment.

 

Edited by Lutz

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2 hours ago, Lutz said:

This is the definition of unladen weight, as laid down in Part 1 of The Road Vehicles (Construction and Use) Regulations 1986:

 

Unladen weight

 

the weight of a vehicle or trailer inclusive of the body and all parts (the heavier being taken where alternative bodies or parts are used) which are necessary to or ordinarily used with the vehicle or trailer when working on a road, but exclusive of the weight of water, fuel or accumulators used for the purpose of the supply of power for the propulsion of the vehicle or, as the case may be, of any vehicle by which the trailer is drawn, and of loose tools and loose equipment.

 

So it disagrees with the Gov website, but no surprises there!

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