Kerb weight vs max towing weight - braked

Am I correct to assume that the advice now is to tow safely the mtplm of the caravan should be 85% of the mass in service, as kerbweight is difficult to define and mass in service is stated in the V5?

Ken

That is a question that you should direct to those who make the recommendation and not to us laymen in this forum.

Bearing in mind differences in definition between mass in service and kerbweight it would be more appropriate to recommend a weight ratio of 90% if based on mass in service, but that is only my opinion.

Note also that mass in service, as defined in the regulations, is not an actual value for your particular vehicle but rather a generic one applicable to all cars of the same model. It is known to differ from the actual by as much as 150kg.

The closest that one would get to kerbweight is the 'actual mass of the vehicle' shown as item 13.2. in the manufacturer's Certificate of Conformity (not the NCC certificate), but from responses that I have read in other threads and forums, very few certificates seem to have an entry under that number.

There is no law that says the caravan must be lighter than the car.

well you have enlightened me Lutz. Thankyou.

Now this interests me ... because I am thinking of buying the following car:

2013 Vauxhall Insignia 2.0 CDTi ecoFLEX Tech Line 5dr but the BHP is 130

I tried to check it on the match thing but couldn't find a 2013 so went for a 2012 and it was all green ticks apart from the 87% kerb weight ratio but I can live with that then it said:

BHP per ton : 39
The car's engine power is quite low to tow this caravan. It may be sluggish and uncomfortable on hills or at junctions.

But when I go on TOWCAR.INFO I can choose a 2013 Insignia but it doesn't list my swift so I went for the nearest match and it gives 82 % says its an excellent match and then its says:

Mountains

On most motorways inclines (1:20) driving is easily possible in the 3th gear with 50 mph and even full throttle with 60 mph. Hill starts are possible even on steep slopes up to 16%, if the front wheels have sufficient traction. While driving the engine has enough power to drive on every normal road.

So ... my dilemma is ... will it pull comfortably or not?

And as a final question, can the car be legally remapped to give it more BHP?

Thanks

I went to weighbridge with nearly full tank , empty car and stood on weighbridge to get a definitive idea  as EU definition

 I tow with Passat estate near to 92%   weight was 1660 +/- 20 Kg

 log book gives 1572 mass in service plus me at 65Kg seems about right

I use Reich CWC to check van.   interestingly the weight differences between each tyre is about 100kg everything is located down one side of our van 

Tows very well and is economical .Never had any problem

Keep towing speed around  50

Just two short comments:

There is no EU definition of kerbweight, if that is what you mean. The definition covers mass in running order, which is the same as mass in service, but not kerbweight. Kerbweight is only defined in UK Construction and Use Regulations.

Mass in service, or mass in running order, already includes 75kg for the driver and sundry items.

Lutz. the man. question-the 85% recommendation, seeing that they say the cars mass in service ( mine is 2006kg ) does that mean the caravan miro is used or the mtplm. if using the cars weight un-laden so to speak then shouldn't the caravan be the same as in un-laden. just a thought.

No, the weight ratio recommendation is always based on a worst case scenario - the caravan loaded as heavy as possible, towed by the car as light as possible.

Mass in service, by the way, is unlikely to represent the actual weight of your car because by the way mass in service is defined, it corresponds to the weight of the car in its basic form without any factory-fitted options. The difference between mass in service and actual weight can, in extreme cases, be as much as 150kg. So any weight ratio calculated using mass in service will always result in a very conservative figure.

thanks Lutz. I thought that mass in service was with full tank and driver at approx. 75kg and kerbweight was of the production line. took mine to a weigh bridge and with full tank and without me came in at 1970kg, me being a fat b----d adds another 108kg to that =2078kg. plus the wife and load. to me that's more sensible as the car cannot tow without me in it. with a rough guess of wife and load would give me a match of 80%. Or is it better to think as long as the van is lighter than vehicle no problem. cheers.