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Treesparrow

Weights and limits question

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15 minutes ago, beejay said:

 

Looks like a  Utilabrake 9 seat conversion by Martin Walter of Folkestone often, but incorrectly, called Dormobiles which was a motor caravan or camper van..

I worked at Vauxhall when these were produced.  Demonstrated them all over the UK and drove many variations. Once took a milk van conversion with low ratio rear axle from the Luton factory to North Wales (pre motorways!) at 45 mph max.  The bare chassis with just a front scuttle and windscreen was a hairy beast to drive when taking it from factory to bodybuilder for assessment..

 

NB. A four-speed gearbox was optional on later models.

Edit:

Utilabrake = mix of utility and shooting brake.

Dormobile = from 'dormir' French to sleep

 

 

 

Was the Utilabrake what we'd now call a MPV?

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18 hours ago, Grandpa Steve said:

 

Why ???

Because that is the important weight not the fixed figure worst case weight

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1 hour ago, R0G said:

Because that is the important weight not the fixed figure worst case weight

 

You are talking about an arbitrary percentage that has no standing in law, that is put forward as the holy grail of towing legend.

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17 hours ago, chrisn7 said:

You should also check the hitch head itself. Some like ALKO may have a load limit cast into the metalwork.

Indeed, my Shogun has a noseweight limit of 140 Kg but the AL-KO hitch is limited to 100 Kg 

2 hours ago, R0G said:

Because that is the important weight not the fixed figure worst case weight

That 85% figure is just made up, it has no legal or practical significance.

My car empty is (off the top of my head) 2350 Kg, fully laden it's 3030 Kg yet it can legally tow 3500 Kg so 85% has no relevance whatsoever.

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2 hours ago, R0G said:

Because that is the important weight not the fixed figure worst case weight

 

It's never the same between two trips and alters as the car fuel is used up.

 

If that ratio were ever used the different percentages to 85/100% would be used as guidelines.

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44 minutes ago, Black Grouse said:

 

It's never the same between two trips and alters as the car fuel is used up.

 

If that ratio were ever used the different percentages to 85/100% would be used as guidelines.

As you know, there is nothing magical or precise about 85% or 100% they are, at best, a rough rule of thumb and the weight of a tank of fuel is insignificant compared to the weight of the rest of the car and its load.

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What people seem to forget in the discussion of '85%' is the original purpose of the %. It was/is meant to be a guide for novice caravanners seeking to purchase a van that they could be certain would work safely with their towing vehicle and vice versa. Back when it was first promulgated car's often weren't allocated towing limits by manufacturer's so an 'empty' car weight to full caravan ratio was a sensible move. The car's kerbweight was usually published and the caravans MTPLM certainly was, so these were two accessible figures for potential purchasers to use. If you were to use the actual weights they would be guesswork as they altered all the time and the equivalent of 85% KW/MTPLM would be around 70% to 75% Loaded weight/MTPLM.

 

The industry has declined to alter it's advice on the ratio for novice caravanners, probably on  the basis that it can't be seen to be potentially advising an increase of risk.

 

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Posted (edited)

If I tow my cars legal tow limit when its empty I'd be towing @ 149%

 

If I tow my cars legal tow limit when its fully laden I'd be towing @ 115%

 

So in both scenarios nowhere near either 85% or 100%

 

In reality I tow a 2000 Kg caravan which with an empty car would be 85% and with a fully laden car would be 66% so that should keep the worriers happy.

Edited by Borussia 1900

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6 minutes ago, Steamdrivenandy said:

What people seem to forget in the discussion of '85%' is the original purpose of the %. It was/is meant to be a guide for novice caravanners seeking to purchase a van that they could be certain would work safely with their towing vehicle and vice versa. Back when it was first promulgated car's often weren't allocated towing limits by manufacturer's so an 'empty' car weight to full caravan ratio was a sensible move. The car's kerbweight was usually published and the caravans MTPLM certainly was, so these were two accessible figures for potential purchasers to use. If you were to use the actual weights they would be guesswork as they altered all the time and the equivalent of 85% KW/MTPLM would be around 70% to 75% Loaded weight/MTPLM.

 

The industry has declined to alter it's advice on the ratio for novice caravanners, probably on  the basis that it can't be seen to be potentially advising an increase of risk.

 

It would be great for the industry if someone would fund a proper study into whether or not the weight ratio actually mattered, exactly what effect it had and what the critical numbers were. 

Anybody got a spare couple of £Million?

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13 hours ago, marchie1053 said:

If Plod stops you and asks you 'whether you have a licence for this vehicle, sir?', you could confuse him/her by asking whether they mean a licence to drive it or fly it ...

 

Steve

 

Which driver is he asking ?  The one at the front or one of two at the rear :wub:

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12 hours ago, beejay said:

 

Looks like a  Utilabrake 9 seat conversion by Martin Walter of Folkestone often, but incorrectly, called Dormobiles which was a motor caravan or camper van..

I worked at Vauxhall when these were produced.  Demonstrated them all over the UK and drove many variations. Once took a milk van conversion with low ratio rear axle from the Luton factory to North Wales (pre motorways!) at 45 mph max.  The bare chassis with just a front scuttle and windscreen was a hairy beast to drive when taking it from factory to bodybuilder for assessment..

 

 

Looks as though we were at Vauxhall at about the same time. Before I left Luton to work in the Dunstable plant I was involved in pilot build of the CF van.

27 minutes ago, Stevan said:

It would be great for the industry if someone would fund a proper study into whether or not the weight ratio actually mattered, exactly what effect it had and what the critical numbers were. 

Anybody got a spare couple of £Million?

 

I would imagine that some work must have been done in Germany because of their differentiated legal weight ratio limits to allow one to tow at 100km/h (30%, 80%, 100%, 110% 120%), depending on how the trailer is technically equipped.

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3 hours ago, Stevan said:

It would be great for the industry if someone would fund a proper study into whether or not the weight ratio actually mattered, exactly what effect it had and what the critical numbers were. 

Anybody got a spare couple of £Million?

 

Agreed, it would be an interesting study for sure.  I've mentioned before, in the US for example, travel-trailers (caravans) often resemble (and weigh about the same) as some static caravans, although towed by some hefty pick-up or other SUV, the laden weight is often above the tow vehicles kerbweight, BUT they have other influencing factors dictating a safe/stable tow (set-back axles, weight distributing hitches and many more). 

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Posted (edited)
15 minutes ago, GaryB1969 said:

 

Agreed, it would be an interesting study for sure.  I've mentioned before, in the US for example, travel-trailers (caravans) often resemble (and weigh about the same) as some static caravans, although towed by some hefty pick-up or other SUV, the laden weight is often above the tow vehicles kerbweight, BUT they have other influencing factors dictating a safe/stable tow (set-back axles, weight distributing hitches and many more). 

 

The set-back axles increases the noseweight significantly while the weight distribution hitches allow tow vehicles to cope with that extra noseweight - it's that increase in noseweight % that makes high towing ratios acceptable and safe.

 

If only we could get European car makers to use 10% of towing weight as the minimum noseweight instead of the 4% required under Type Approval - ironically many models sold in Europe have much higher noseweight limits when sold in Australia and North America.

Edited by Black Grouse

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11 minutes ago, Black Grouse said:

 

The set-back axles increases the noseweight significantly while the weight distribution hitches allow tow vehicles to cope with that extra noseweight - it's that increase in noseweight % that makes high towing ratios acceptable and safe.

 

If only we could get European car makers to use 10% of towing weight as the minimum noseweight instead of the 4% required under Type Approval - ironically many models sold in Europe have much higher noseweight limits when sold in Australia and North America.

 

European manufacturers have little incentive to increase noseweight limits because any increase would require appropriate structural reinforcement measures which will only add on-cost for all those who will never use their vehicle to tow and increase weight, which is not conducive to low emissions.

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6 hours ago, Borussia 1900 said:

Indeed, my Shogun has a noseweight limit of 140 Kg but the AL-KO hitch is limited to 100 Kg 

 

Where on the hitch would one find this figure limiting you to a maximum of 100kg?

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33 minutes ago, Durbanite said:

Where on the hitch would one find this figure limiting you to a maximum of 100kg?

 

It's in the handbook for the caravan, and for the car it is on the approval label attached to the hitch, describes as the "S" value or Vertical Load

image.png

 

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Posted (edited)
46 minutes ago, Durbanite said:

Where on the hitch would one find this figure limiting you to a maximum of 100kg?

On mine (I'm talking about the caravan hitch, not the towbar) its embossed into the side, it says S 100 Kg. 

 

S= Stutzlast (Noseweight)

Edited by Borussia 1900

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The noseweight limit is also displayed as Axle 0 on the statutory plate and that is the one that that takes precedence over all others.

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2 hours ago, Grandpa Steve said:

It's in the handbook for the caravan, and for the car it is on the approval label attached to the hitch, describes as the "S" value or Vertical Load

Thanks.  I was wondering if it is actually stamped on the hitch as our ALKO hitvh has to be rated for 150kg??

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Posted (edited)
8 minutes ago, Durbanite said:

Thanks.  I was wondering if it is actually stamped on the hitch as our ALKO hitvh has to be rated for 150kg??

It will be on the coupler and also on the Inertia device, on the trailer and on the Towbar of the towing vehicle.

The lowest of all of these is the one to go by.

It's not at all unusual to see a coupler rated for a higher figure than the inertia device.

Edited by Towtug

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Posted (edited)
4 hours ago, GaryB1969 said:

 

Agreed, it would be an interesting study for sure.  I've mentioned before, in the US for example, travel-trailers (caravans) often resemble (and weigh about the same) as some static caravans, although towed by some hefty pick-up or other SUV, the laden weight is often above the tow vehicles kerbweight, BUT they have other influencing factors dictating a safe/stable tow (set-back axles, weight distributing hitches and many more). 

Numerous studies have effectively been done, if you count the fact that every type approved trailer (and those that are IVAd to a degree) are subjected to a General Safety test which checks on the "driveability", that is why sometimes you see some peculiar nose weight limits.  The problem is that it's an inexact science,  with so many variables that unless you standardise layouts and equipment you will never get a meaningful result.

As an example I recently tested a 2500 kg generator on a twin axle chassis behind the new Landcruiser. With a full fuel tank it had 75kg noseweight and towed like a pig on roller skates, with an empty tank the noseweight increased to 130 and it towed even worse.  Coupled it up to a Disco4 same weights and it was no problem. 

Hooked it up behind a Transit pickup and it towed well at the higher noseweight, but badly (crapisnt bad language is it) at anything else.

So unfortunately it looks like to get any meaningful ratio you would need to take all the features of the trailer and  all the features of every towcar combination into account. One manufacturer did create an algorithm for design, which was reasonably accurate  but to do this but it relied on having access to data from the vehicle manufacturer that was just not commercially available.

Edited by Towtug

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1 hour ago, Lutz said:

The noseweight limit is also displayed as Axle 0 on the statutory plate and that is the one that that takes precedence over all others.

 

Is that on the car or the caravan, please be specific!

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Posted (edited)
7 minutes ago, Grandpa Steve said:

 

Is that on the car or the caravan, please be specific!

 

I was referring to the hitch limit which is of course on the caravan itselft's the one on the caravan. The car doesn't have an Axle 0. The definitive noseweight limit for the car will only be found on the type approval plate on the towbar.

Edited by Lutz

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Posted (edited)

Apologises  Durbanite, I was sure mine was 100 Kg (I’m blind as a bat), I’ve just zoomed in and seen it’s actually 150 Kg!!

Happy days, that means I’m now limited to my car’s maximum of 140 Kg

0DBF5670-E1C7-451C-9388-7CE717455AD5.png

Edited by Borussia 1900
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Just been out to check my Lunar - the hitch is 150kg as it has S150 cast in but the VIN plate gives 100kg for axle 0 - maybe Lunar will do an upgrade sticker and raise it to 150?

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