Kerb weight vs max towing weight - braked

ellie2761

I have a swift challenger 4 berth 530 2003 with an mtplm of 1429kg

I am looking for a new tow car and all these different weights are really confusing me.

I saw a 2011 Skoda Superb estate with a kerb weight of 1494 and a  Max. Towing Weight - Braked of 1800 but when I put this car into the clubs checker its 97%.

I also looked at Insignia Estates they don't list a kerb weight  but they claim their Max. Towing Weight - Braked is 1600-1700 there are loads of models and the clubs checker doesn't have the info on some of them, those I found on a 'range search' don't seem to come close to the magic 85%.

 I don't understand what the max towing weight means. Can anyone explain to me how a car with such a low kerb weight can tow 1800?

Thanks.

Tinwheeler

The max towing weight is a figure set by the manufacturer stating the maximum the car is capable of pulling in certain circumstances. It does not mean it is sensible or safe to tow that weight on the road.

If you stick to around 85% of the car's kerb weight, you won’t go too far wrong. It is only a recommendation, not a rule, so you have some scope for common sense variations. I’ve not yet come across a car that doesn't have the kerb weight stated somewhere in the brochure or website. I suspect it’s a legal requirement that the weight is stated.

 

 

 

Lutz

Max. towing weight and kerbweight are completely independent of each other. The max. towing weight figure is determined by the car manufacturer on the basis of tests. Regulations specify minimum requirements regarding the ability to start a number of times on a 12% gradient  but any self-respecting manufacturer will carry out a lot more than that, including braking and handling tests as well as making sure that engine cooling performance is adequate.

Lutz

Some cars have a max. towing weight less than 85% of its kerbweight, so check first.

Tigi

As per Tinwheeler some heavier SUV`s in particular have a max towing weight far in excess of the 85% of the kerbweight the weight which is normally considered safe for novice towers to work to. The manufacturer gives the max towing limit based on the cars mechanical capabilities e.g. braking clutch engine power etc. Obviously if you are towing a caravan that is well under the max towing weight it is to your advantage from a wear and tear aspect.

ChrisRogers

My 2012 Skoda Octavia Estate 4x4 handbook states 1,495kg, (unloaded weight ready for work!!!!!!), that weight is on the V5C mass in service, tow limit of 1,600kg. My van mtplm is 1,318kg, giving 88% ratio, the C&CC matching service also gives 88%, C&MC matching service gives it 92% ratio. For me it tows very well, very stable, with 75kg noseweight.

The newer model is about 75kg lighter with a 2,000kg tow limit.

Lutz

Just a note:

The V5c mass in service is not exactly the same as kerbweight, but for most intents and purposes it will do. In fact, manufacturers often refer to mass in service as kerbweight, which of course adds to the confusion.

ellie2761

Thanks for the responses, I understand it better now.

I did not find the kerb weight of the Insignia and even google didn't help so I eventually downloaded a car manual which did have it. So now I can try to find a match, and maybe try and find some insignia owners that tow for some advice!

In response to Chris Rogers comment about C&MC vs C&CC matching service I wonder why the percentages are different? My current car comes up at 92% on C&MC because its limited with it being a 7 seater but I want to downsize and I'm really struggling to find something suitable, to get close the magic 85% it appears I have to find a car with a kerb weight of 1650+ and there's not a lot of cars out there to fit my budget.

Lutz

Kerbweight is specific to each and every car. Any published data can therefore only be a rough guide. Besides, manufacturers aren't under any obligation to provide true kerbweight figures, so they are hard to come by. Usually, the figures that you find in brochures, handbooks, websites are based on the mass in service figure, but these can differ from actual kerbweight by up to 150kg, usually on the low side. This means that any weight ratio that you may have calculated based on figures that you have found will at least be on the conservative side.

Lutz

Depending on where the matching service has got its information from, variances of 4% like the one that you have come across are not unusual, bearing in mind that their figures can only be a rough guide anyway. The weights that car manufacturers are legally required to provide do not include kerbweight. Without knowing the actual kerbweight of your particular car, you can't expect anything more accurate.

EasyT

Certainly the kerbweight is not easy to find for our tow car; not shown on plate or documents and the CC checker is well out for ours.

Lutz

Like I said, if you want to know the kerbweight really accurately there's no alternative but to actually weigh the car because you won't find an accurate figure anywhere else.

EasyT

I did find an accurate figure on Towcar.info and also on Caravan Talk but as you say Lutz the only way to be sure is usually to weigh the vehicle as it is difficult to know which of the many values for kerbweight is correct.

Lutz

If you did find an accurate figure which actually corresponded to your particular car you were lucky and it was pure chance. It would be wrong to assume that Towcar.info, in general, have access to any accurate data.

EasyT

Much my thoughts as well. 

If you search the web there are at least as many wrong answers as right ones. 

lornalou1

surely when a car comes of the line it has a kerbweight. then you fit a towbar at say 30/40kg so I would say the weight of the car has now changed and needs to be added to the first kerb weight. I took my car to local builders merchant last week and weighs 1970kg without me in it and a full tank. mass in service states 2006kg and hand book states 1875kg kerb weight. I am the only driver of the car so could add another 108kg to that.(yes I am a fatty) so with the wife as well makes the total 2153kg before loading up for a trip.

Lutz

Yes, of course the car has a kerbweight when it comes off the line, but it's not documented anywhere.

It's rather unusual for the stated mass in service to be greater than kerbweight. There's obviously something wrong there because, taking differences in definition into account, that should never be the case. That the actual weight is more than any quoted kerbweight, however, is only to be expected.

lornalou1

Lutz, I agree. never get the same match with different websites. i'll take the mass in service that's on v5 as correct but even then they don't add the weight of the tow bar but then again not everybody tows.

Lutz

Mass in service not only doesn't include a dealer-fitted towbar but also doesn't include any factory fitted options either, so using the V5c mass in service figure will always give you a conservative result.

EmilysDad

Mercedes' weights/masses must be way out then as just about everything is an option

everard17

Having used our Insignia Estate as a tug for our Lunar Clubman for the last five years I would say it makes an ideal towcar. We have travelled to all four corners and never experienced any problems,it tows our 1500mtpl van with ease.

 

 

KenofKent

Lutz, I am confused. My Freelander 2 has a kerbweight of 1785 kg. My V5 shows a mass in service of 1958. My Swift tech. handbook says not to add the weight of a tow bar to kerbweight when using the 85% formula. Can you advise me what weight I can tow using 85% formula. My vehicle manufacturer states max tow weight is 2000kg, but of course I would never do that.

Thanks, Ken

Lutz

Where did you get the kerbweight figure from? If it is not specific to the particular chassis number of your Freelander then it can be no more than a very rough guide. The only way you are going to get an accurate figure is to have the car weighed, but then, of course it will include the weight of the towbar. I have not come across any car manufacturer that provides actual kerbweight figures for each vehicle as it comes off the line and I know of no other reliable source, so there is no alternative . 

A kerbweight figure less than mass in service is very suspect anyway.

lornalou1

Lutz, I think your the knowledge so here goes. as said earlier can I ask what I will be better using.

1- 2006kg as on the V5 ( mass in service )

2- 1970kg as weighed on a bridge ( without me in it )

3-2200kg approx. with me/wife and load.

Cheers pal.

Lutz

No. 2 (1970kg) is about as close as you are going to get if it was with a full tank of fuel, although the 36kg difference to mass in service, if you use that, is not going to affect the end result appreciably (less than 2% - which is negligible)

lornalou1

Thanks Lutz. that gives me a 91% match with my van if I max to the limit which I try not to so can cope with that.

KenofKent

Thank you Lutz. The kerbweight figure came from a Landrover site but did have a rider that it was the lightest weight. Would I be correct then in matching to 85% of my mass in service.

Ken

Cornersteady

can I ask which weight would legally matter? 

Lutz

In practice none because there is no legal requirement based on kerbweight/mass in service, etc. The trouble is that as far as the definition of kerbweight is concerned, the term is often interpreted differently by convention than in the way it is defined legally, even by the industry.

However, regulations do provide for the need for car manufacturers to document mass in running order (same as mass in service) and, with the introduction of 1230/2012/EU, the actual mass of the vehicle, neither of which correspond 100% to the definition of kerbweight.

Cornersteady

Ok thanks for the reply

lornalou1

so the 85% rule is a bit of a waste of time really as kerbweights are not usually found on the V5 doc now but the mass in service is. I suppose that as long as the van is lighter than the car, legally thats ok. passed test before 97 so total mass is irrelivant.