Kerbweight v 85% ratio

[Dave1007]

Hi
Looking at a towcar with 95% towmatch for my caravan. As an experienced driver my question is if I place the awning in the car will that decrease this ratio?

 

[RogerL]

No, it doesn't alter the "Towing Ratio"

 

[Buckman]

The 85% is only a guideline and not law however it is sensible to keep under 95% of the vehicle's kerbweight. Also some insurance companies restrict towing to a maximum of 95% one being Towergate. With modern cars I would think that up to 95% of the kerbweight of a car is safe, but that is up to each individual to determine for themselves.

 

[Raywood]

The awning will not increase the kerb weight calculation but will certainly help the car control the caravan and with some load allowances being too low help keep you within the caravans MTPLM. Do try to keep it between the axles for the best distribution of the weight.

 

[Woodentop]

85% for clarification is guidance for drivers new to towing. Once you have experience under your belt 100% is acceptable and quite safe.

 

[ProfJohnL]

As others have stated changing the load plan does not change the oft quoted towing ratio. The towing ratio is a very coarse and inaccurate way of comparing outfits and helping to choose cars or caravans. It assumes a worst case scenario of an empty car and a fully laden caravan on which to base the calculation.

Of course every change in the loading scheme does change the effective ratio, and generally most outfits will in reality be better than the calculated ratio.

Domestic drivers should aim to keep the car heavier than any trailer, but must also ensure they do not exceed any of the legal weight limits such as max axle, tow ball and vehicle weight limits.

 

[JezzerB]

Kerbweight-mmm-no car going on holiday is going to be at kerbweight- and if the weight of the car has anything to do with controlling the caravan the heavier the car to the weight of the caravan -should then be better-I'd never put an awning in the caravan for that very reason. However there's far more to it -tyre pressures speed weight distribution all count too. Most on here will know I am a kerbweight denier-I think it a starting point perhaps but just that and dangerously simplistic-very heavy Discoveries topple over-because owners think they have the king tug of the road-and their c of g is high!

 

[Paullus1959]

The 85% towing rule is not enforceable, it's only a guide, nevertheless, a useful guide.
It was introduced donkey's years ago when caravanning started to became popular.
Back then caravans, which were built out of tree wood and heavy and the cars used to tow them, didn't have sophisticated stability control systems. This resulted in many people coming to grief. The 85% ratio was introduced to avoid the tail wagging the dog disaster scenario.

What Is The 85% Towing Rule? Here Are The Facts!

You've heard about the 85% towing rule, but what does it mean, how to work it out and is it legally enforceable? We have the facts!

www.towingcapacity.co.uk

View: https://www.youtube.com/watch?v=4jk9H5AB4lM


I've towed at around 88% ratio and it's absolutely fine in good conditions. However, things sometimes got a bit twitchy on the motorway and dual carriageways where driving conditions were less than ideal e.g.

• windy conditions
• dropping in and out of the the wheel ruts caused by the heavies on multi-lane carriageways. These ruts are just wider than the track of the caravan and tow-car but difficult to stay out of completely.
• undulating road surfaces and adverse camber
• the gust of wind caused when vehicles only the size of a Transit van come past at speed.

I traded that tow car in for my current one that's giving me a 74% ratio and it's far more relaxed. Nevertheless, it still has the odd twitch when conditions are poor despite the Al-Ko ATC, anti-snake hitch and my car's stabillity controls.
There's no way I would feel comfortable at a 100% ratio and travel at 60mph on a motorway or dual carriageway in poor conditions which are sometimes difficult to anticipate, let alone see.
Ultimately, it is inapropriate use of speed for the conditions that is the root cause of towing and driving disasters in general.
This is why some inexperienced drivers may unfortunately come to grief under the new changes in the towing regulations.

 

[JezzerB]

I'm surprised you found 88% twitchy but all outfits are different. We didn't get any twitchy at 113% . In fact so rock solid when yours truly missed a humpback bridge sign severe hard braking and an airborn caravan didn't cause a twitch. Made the driver twitch though!!! And His wife was not a happy bunny!

 

[Paullus1959]

I'm surprised you found 88% twitchy but all outfits are different.

Indeed, your Buccaneer Cruiser is a twin axle whereas my Coachman VIP is single.
Twins are more stable by design.

 

[JezzerB]

Our 113% was a single axle Bailey Pegasus towed by a Dacia duster. Petrol 1.6 4x4. No ATC either. Our Navara tows the Buc. Well under 100% but little difference stability wise.

 

[Hutch]

You can't change the manufacturers kerb weight, but you can change your towing ratio by moving equipment around as Raywood correctly states.

 

[Buckman]

You can't change the manufacturers kerb weight, but you can change your towing ratio by moving equipment around as Raywood correctly states.

I would think that when you have extras added before delivery as part of the order, the manufacturer's kerb weight will change.

 

[RogerL]

I would think that when you have extras added before delivery as part of the order, the manufacturer's kerb weight will change.

Maybe, maybe not - the extra-cost factory-fitted options I ordered on my Touareg are around 150 kg extra weight (panoramic sunroof, diesel cabin heater, long-range fuel tank and electric towbar) but the quoted kerbweight is the same as a standard model.

 

[JTQ]

Maybe, maybe not - the extra-cost factory-fitted options I ordered on my Touareg are around 150 kg extra weight (panoramic sunroof, diesel cabin heater, long-range fuel tank and electric towbar) but the quoted kerbweight is the same as a standard model.

That seem "par for the course", in that quoted kerb weights typically refer to the example on which type approval for the model was based, nothing to do with actual weight of individual client build specification, or even more standard configurations offered for a model, eg "S" "SL, or "Lux" etc. An area where quite significant additional mass can occur.

Though of course for towing dynamics where mass is a factor, that is only affected by real masses not paperwork masses; an aspect that makes matching based on some arbitrary, historic, paper "kerb weight", technically illogical.

Often it is stated as a guide, but often also given more credence than it deserves, or "the best guide available". Sadly if that was the best available then those fronting it are failing us, even a casual technical look at other features of vehicles could add a lot more meaningful value.

 

[RogerL]

That seem "par for the course", in that quoted kerb weights typically refer to the example on which type approval for the model was based, nothing to do with actual weight of individual client build specification, or even more standard configurations offered for a model, eg "S" "SL, or "Lux" etc. An area where quite significant additional mass can occur.

Though of course for towing dynamics where mass is a factor, that is only affected by real masses not paperwork masses; an aspect that makes matching based on some arbitrary, historic, paper "kerb weight", technically illogical.

Often it is stated as a guide, but often also given more credence than it deserves, or "the best guide available". Sadly if that was the best available then those fronting it are failing us, even a casual technical look at other features of vehicles could add a lot more meaningful value.

Like the Towing Ratio, the unladen weight is a "worst case" figure - I just work on the lower the actual ratio the more inherently stable. Nominally my outfit is 65% but with them loaded normally (for us) it's more like 50%.

 

[Lutz]

Maybe, maybe not - the extra-cost factory-fitted options I ordered on my Touareg are around 150 kg extra weight (panoramic sunroof, diesel cabin heater, long-range fuel tank and electric towbar) but the quoted kerbweight is the same as a standard model.

That doesn't make sense. All those items that you mention by definition alter the kerbweight. What they don't do is alter the mass in running order/mass in service.

 

[Raywood]

Agree if you fit extras they do increase the real life kerb weight, but the quoted one will be the theoretical weight that was the car when it left the factory. These will eat into the GVW though and limit the weight you can add by that amount, 150 kg could be a fair bit gone. .

 

[Lutz]

Agree if you fit extras they do increase the real life kerb weight, but the quoted one will be the theoretical weight that was the car when it left the factory. These will eat into the GVW though and limit the weight you can add by that amount, 150 kg could be a fair bit gone. .

Neither a brochure, nor an owner's handbook and not even the V5c quote the actual weight of the vehicle as it left the factory. The only document that states its actual weight is the type approval Certificate of Conformity and that is seldom passed on to the vehicle owner in the UK. (It's needed elsewhere, though, in order to be able to register the vehicle.)

 

[ProfJohnL]

The towing ratio so commonly quoted bears no relation to the real world weights of the outfit. It uses "kerbweight" which is rarely an accurate representation of tow vehicle, not only becasue few cars actually meet their quoted kerbweight, and of course when towing the car will already have some additional load.

Whilst the towing ratio may not be the real world values for an outfit, it is at least one way of making some consistent comparisons between outfits.

another other fundamental issue with the ratio is it takes no account of teh vehicles legal or technical specifications, and it can recommend an outfit that is not actual legal to drive.

 

[Lutz]

Vehicle manufacturers are under no obligation to quote kerbweights and even for those that do, close scrutiny will reveal that although they may call the figures that they quote 'kerbweight' they aren't the kerbweight at all, but often the mass in running order under a different name.

 

[ProfJohnL]

Confusion reigns!,

 

[Hutch]

The forum contributers are getting into the nity grity bits of pedantics again , and are going to scare off a member of the forum, asking a straight forward question.

 

[Parksy]

Hi
Looking at a towcar with 95% towmatch for my caravan. As an experienced driver my question is if I place the awning in the car will that decrease this ratio?

No it won't.
All of the peripheral responses are forum hot air which don't answer your question.

 

[JezzerB]

Simple. Ignore kerb weight now you know it's 95% minimum it's fine. Load the car yes put the awning in it and real time kerb weight increases and you are even better off. Stop worrying it will be fine. Load the car not the caravan is our mantra that never fail oh within legal limits of course.