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Do We Place Too Much Emphasis On Kerbweights And Mtplm's?


phil1041
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I have just returned from a week at Incleboro Fields CC site in Norfolk. Before setting off i decided to take my fully loaded outfit to the weighbridge, a very interesting exercise.

 

Now, using the Kerbweight of my vehicle (1714 kg full tank of fuel) and my vans MTPLM (1686kg) this gives a towing ratio of 96%, frowned on by some.

 

The actual weights were, vehicle 2110kg, van 1600kg towing ratio 78%.

 

Now i must say that i do load the car as much as possible as there are only two of us plus the Retreiver who has the whole of the boot, so the back seats are loaded with the awning and frame plus chairs and a tool box etc.

The van was fully laden with food clothes etc sufficient for a one week stay however.

 

So, do we overemphasise the stated weights, surely its the actual weights that really count?

 

Incidentally, the car towed perfectly, sitting at 60mph in 6th on the A1 with no problem returning just over 27mpg according to the computer (not sure how accurate that is however).

 

 

Phil.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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Phil

Sorry dont agree with you.

 

The guidline of the caravan MTPLM to tow vehicle kerbweight is used to give an indication of stability of any particular outfit with a guidance of 85% for an inexperienced tower. The intent is to enable users to choose a suitable car/caravan combination.

 

If you change your parameters then you are not comparing apples with apples and had they chosen to use the vehicle gross weight then the recommendation or the weight ratio would have been considerbly less.

 

Taking your example, your outfit has a certain stability. It does not become more stable by changing the method of calculation. Using the correct method you say it is 96% and calculating on actual weights it is 78%. It is still the same outfit and the stability for any given loading will not change.

Brian

 

PS Although I have used the MTPLM above, the guideline is for the caravan actual weight to be used. However most people load their caravan to the maximum (and sometimes over) so it is simpler to use the MTPLM

Edited by BrianI
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I have just returned from a week at Incleboro Fields CC site in Norfolk. Before setting off i decided to take my fully loaded outfit to the weighbridge, a very interesting exercise.

 

Now, using the Kerbweight of my vehicle (1714 kg full tank of fuel) and my vans MTPLM (1686kg) this gives a towing ratio of 96%, frowned on by some.

 

The actual weights were, vehicle 2110kg, van 1600kg towing ratio 78%.

 

Now i must say that i do load the car as much as possible as there are only two of us plus the Retreiver who has the whole of the boot, so the back seats are loaded with the awning and frame plus chairs and a tool box etc.

The van was fully laden with food clothes etc sufficient for a one week stay however.

 

So, do we overemphasise the stated weights, surely its the actual weights that really count?

 

Incidentally, the car towed perfectly, sitting at 60mph in 6th on the A1 with no problem returning just over 27mpg according to the computer (not sure how accurate that is however).

 

 

Phil.

 

 

 

 

Hi Phil, this subject is becomming an obsession of mine. Firstly I want to use your info, but I am in no way criticising your methods. :)

According to Honda a CR-V 2. 2 i-CTDI SE 5dr( is this yours?) the kerb weight is 1660kg, the max weight is 2160kg and the nose weight is 100kg.

Firstly using the nose weight, if you put what you say you do on your back seat and then stick a 3 - 4 stone dog in the boot you could be seriously affecting you rnose weight limit and therefore exerting to much pressure on the rear axle thus releasing pressure on the front axle therefore lightening your front wheel and steering grip.

 

Second, when you weighed the outfit on the weigh bridge did the car weight include all running weight i. e driver and passenger. I know you said fully loaded, but as a lorry driver who has to use various weigh bridges on a daily basis some have driver in and some insist on driver out. if you were out when you weighed it then assuming you weigh more than 50kg your car would be exceeding its maximum permissable weight and therefore breaking the law.

 

I am interested in this because when you see small 4x4s towing big vans they can sometimes look a bit odd, like a mouse pulling a trailer with an elephant on it :lol:

 

Ultimately it is scenarios like yours which show up the legislation for the farce that it is. Why can't we just have a yes you can or a no you can't. At least then we all know where we stand. Once again I am not criticisng you as it seems that your lay-out gives you a stable unit which obviously makes you feel more comfortable and safer on the road. Happy 'vanning. :D

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I have just returned from a week at Incleboro Fields CC site in Norfolk. Before setting off i decided to take my fully loaded outfit to the weighbridge, a very interesting exercise.

 

Now, using the Kerbweight of my vehicle (1714 kg full tank of fuel) and my vans MTPLM (1686kg) this gives a towing ratio of 96%, frowned on by some.

 

The actual weights were, vehicle 2110kg, van 1600kg towing ratio 78%.

 

Now i must say that i do load the car as much as possible as there are only two of us plus the Retreiver who has the whole of the boot, so the back seats are loaded with the awning and frame plus chairs and a tool box etc.

The van was fully laden with food clothes etc sufficient for a one week stay however.

 

So, do we overemphasise the stated weights, surely its the actual weights that really count?

 

Incidentally, the car towed perfectly, sitting at 60mph in 6th on the A1 with no problem returning just over 27mpg according to the computer (not sure how accurate that is however).

 

 

Phil.

I see where your coming from but in my opinion (and dont take this the wrong way) your asking a lot of a Honda crv which is a compartively small and light weight softroader with 4 wheel drive to tow a big heavy Bailey senator twin axle and while its perfectly legal, if it were me i would want something with a kerbweight of 2 tons and at least 2. 5 diesel 180 bhp .

Also size wise the CRV looks small and not very suitable for towing that size of van however each to there own

 

neil

Edited by neil and lena
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Phil

Sorry dont agree with you.

 

The guidline of the caravan MTPLM to tow vehicle kerbweight is used to give an indication of stability of any particular outfit with a guidance of 85% for an inexperienced tower. The intent is to enable users to choose a suitable car/caravan combination.

 

If you change your parameters then you are not comparing apples with apples and had they chosen to use the vehicle gross weight then the recommendation or the weight ratio would have been considerbly less.

 

Taking your example, your outfit has a certain stability. It does not become more stable by changing the method of calculation. Using the correct method you say it is 96% and calculating on actual weights it is 78%. It is still the same outfit and the stability for any given loading will not change.

Brian

 

 

Brian the op may not be comparing apple with apples but there is a degree of sense in what he says.

Providing the overall outfit is legal I think this is most sensible and would have to disagree with your comment about the loading not changing things.

Had the op done it the other way around and loaded the van to it,s max and stayed within his towing limits I for one would think this to be more unstable than what he has done.

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I've always considered that kerbweight {lightest likelyhood} and MTPLM {heavist likelyhood} are quoted to give a base line to work from.

 

Obviously, hardly anybody tows at these weights so any variance can only be an improvement.

 

Unless everybody is prepared to weigh their van before every journey how can you be sure it's the same weight as the last time?

 

I think too many members are getting paranoid about this.

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Brian the op may not be comparing apple with apples but there is a degree of sense in what he says.

Providing the overall outfit is legal I think this is most sensible and would have to disagree with your comment about the loading not changing things.

Had the op done it the other way around and loaded the van to it,s max and stayed within his towing limits I for one would think this to be more unstable than what he has done.

I was talking about the basic combination stability. How you load it can improve things - Hence my last sentence - It is still the same outfit and the stability for any given loading will not change.

 

Brian

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Hi Phil, this subject is becomming an obsession of mine. Firstly I want to use your info, but I am in no way criticising your methods. :)

According to Honda a CR-V 2. 2 i-CTDI SE 5dr( is this yours?) the kerb weight is 1660kg, the max weight is 2160kg and the nose weight is 100kg.

Firstly using the nose weight, if you put what you say you do on your back seat and then stick a 3 - 4 stone dog in the boot you could be seriously affecting you rnose weight limit and therefore exerting to much pressure on the rear axle thus releasing pressure on the front axle therefore lightening your front wheel and steering grip.

 

Second, when you weighed the outfit on the weigh bridge did the car weight include all running weight i. e driver and passenger. I know you said fully loaded, but as a lorry driver who has to use various weigh bridges on a daily basis some have driver in and some insist on driver out. if you were out when you weighed it then assuming you weigh more than 50kg your car would be exceeding its maximum permissable weight and therefore breaking the law.

 

I am interested in this because when you see small 4x4s towing big vans they can sometimes look a bit odd, like a mouse pulling a trailer with an elephant on it :lol:

 

Ultimately it is scenarios like yours which show up the legislation for the farce that it is. Why can't we just have a yes you can or a no you can't. At least then we all know where we stand. Once again I am not criticisng you as it seems that your lay-out gives you a stable unit which obviously makes you feel more comfortable and safer on the road. Happy 'vanning. :D

 

I used a strip type walking pace weighbridge which weighs each axle in turn, so yes it was fully loaded with all passengers and dog!

 

Re your noseweight point, each axle of the car was weighed and was within its stated maximum allowance.

 

Hope this helps.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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I see where your coming from but in my opinion (and dont take this the wrong way) your asking a lot of a Honda crv which is a compartively small and light weight softroader with 4 wheel drive to tow a big heavy Bailey senator twin axle and while its perfectly legal, if it were me i would want something with a kerbweight of 2 tons and at least 2. 5 diesel 180 bhp .

Also size wise the CRV looks small and not very suitable for towing that size of van however each to there own

 

neil

 

 

Please don't take my reply the wrong way either, but i see you use the old X Trail, lower towing limit and noseweight allowance, with all the goodies you have on your van, have you ever weighed your fully loaded outfit?

 

Phil.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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Please don't take my reply the wrong way either, but i see you use the old X Trail, lower towing limit and noseweight allowance, with all the goodies you have on your van, have you ever weighed your fully loaded outfit?

 

Phil.

Phil i can only give you the figures for my old 07 pageant burgundy with all the extras which i still own as my new 09 pageant has not been delivered and the Burgundy has a max weight of 1420 kg MPTLM (upgraded) and the X-trail empty with 50 litres diesel (90%full) is 1640kg checked on two different local weighbridges, noseweight 100kg and towing capacity 2000 kgs (same as CRV) = 86% match if loaded to capacity and unlike many who have never weighed there outfit i do on every long trip without fail and i keep all the weigh tickets . I also check noseweight as well and it is always about 85-87 kgs well within paremeters .

The truma aircon and the oyster sat take about 38-39 kg out of the payload allowance hence the MPTLM upgrade from 1400-1420kgs to part compensate but should i ever go down the twin axle road i would not want to run at such a high percentage 96% as your self

Edited by neil and lena
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I used a strip type walking pace weighbridge which weighs each axle in turn, so yes it was fully loaded with all passengers and dog!

 

Re your noseweight point, each axle of the car was weighed and was within its stated maximum allowance.

 

Hope this helps.

 

Hi phil1041

 

'weighs each axle in turn' is that one at a time or both together?

I think I'd prefer an all up weight and each axle for certainty.

 

neil

Bailey S5 Pageant Auvergne & Vauxhall Signum CDTI

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Phil i can only give you the figures for my old 07 pageant burgundy with all the extras which i still own as my new 09 pageant has not been delivered and the Burgundy has a max weight of 1420 kg MPTLM (upgraded) and the X-trail empty with 50 litres diesel (90%full) is 1640kg checked on two different local weighbridges, noseweight 100kg and towing capacity 2000 kgs (same as CRV) = 86% match if loaded to capacity and unlike many who have never weighed there outfit i do on every long trip without fail and i keep all the weigh tickets . I also check noseweight as well and it is always about 85-87 kgs well within paremeters .

 

 

Well then i sit corrected, i am sure i read that the 05 X Trail only had a 75kg noseweight limit and a proportionaly lower towing limit (not sure what exactly).

 

How on earth do you keep your van under 1420kg with all those extras fitted? i must be doing something wrong.

 

 

Phil.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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Well then i sit corrected, i am sure i read that the 05 X Trail only had a 75kg noseweight limit and a proportionaly lower towing limit (not sure what exactly).

 

How on earth do you keep your van under 1420kg with all those extras fitted? i must be doing something wrong.

 

 

Phil.

The 2000kg tow weight is correct as is the 100kg noseweight and the extras do not add that much if you read my updated post in fact no more than some motormovers something which i do not and will not fit

Edited by neil and lena
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Hi phil1041

 

'weighs each axle in turn' is that one at a time or both together?

I think I'd prefer an all up weight and each axle for certainty.

 

neil

 

 

Its a dynamic bridge that weighs each axle in turn as you drive over it, it then gives you a gross figure for all axles weighed.

 

 

Phil.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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Phil i can only give you the figures for my old 07 pageant burgundy with all the extras which i still own as my new 09 pageant has not been delivered and the Burgundy has a max weight of 1420 kg MPTLM (upgraded) and the X-trail empty with 50 litres diesel (90%full) is 1640kg checked on two different local weighbridges, noseweight 100kg and towing capacity 2000 kgs (same as CRV) = 86% match if loaded to capacity and unlike many who have never weighed there outfit i do on every long trip without fail and i keep all the weigh tickets . I also check noseweight as well and it is always about 85-87 kgs well within paremeters .

The truma aircon and the oyster sat take about 38-39 kg out of the payload allowance hence the MPTLM upgrade from 1400-1420kgs to part compensate but should i ever go down the twin axle road i would not want to run at such a high percentage 96% as your self

 

 

Sorry i did not see your updated post re the additional weights.

 

With respect however, i am not towing at 96%, but as i have proved 78%, ie the fully laden van is only 78% of the weight of the fully laden car.

 

 

Phil.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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Sorry i did not see your updated post re the additional weights.

 

With respect however, i am not towing at 96%, but as i have proved 78%, ie the fully laden van is only 78% of the weight of the fully laden car.

 

 

Phil.

Well thats debatable as to whether you go buy the loaded figures at the weigh bridge or the Hondas kerweight minus the caravan MPTLM as most people do when calculating there car / caravan weight ratio

Edited by neil and lena
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Well thats debatable as to whether you go buy the loaded figures at the weigh bridge or the Hondas kerweight minus the caravan MPTLM as most people do when calculating there car / caravan weight ratio

 

Then lets debate it further, what is the purpose of the 85% GUIDELINE rule? Safety obviously to stop the tail wagging the dog.

 

The GUIDELINE uses the vans MTPLM and the cars kerbweight presumably because it assumes you are going to fully load your van and put nothing (other than fuel) in your car, or because it cannot know how many passengers you carry etc etc.

 

However, if you go to the trouble as i did, of determining the exact weight of both vehicles, then the true ratio, in my case, has to be 78% surely, so how is this figure debatable?

 

 

Phil.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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Then lets debate it further, what is the purpose of the 85% GUIDELINE rule? Safety obviously to stop the tail wagging the dog.

 

The GUIDELINE uses the vans MTPLM and the cars kerbweight presumably because it assumes you are going to fully load your van and put nothing (other than fuel) in your car, or because it cannot know how many passengers you carry etc etc.

 

However, if you go to the trouble as i did, of determining the exact weight of both vehicles, then the true ratio, in my case, has to be 78% surely, so how is this figure debatable?

 

 

Phil.

ok you are obviously happy with these loaded figures and happy enough to run with these weights however the two main clubs would not view your outfit as being a particularly good towing combination because they calculate the suitability of a car and caravan on the Kerweight of the towcar and the MTPLM of the caravan and do not take the laden weight of the car into the equation .

Now we are all entitled to different opinions but in this instance i and many others would prefer to follow the guidelines of the two main clubs when checking suitability, perhaps in this instance we should agree to disagree

Edited by neil and lena
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Its got to be the actual weight figures that count. Providing you stay within the maximum weights allowed for the car axle gross and train shown on the manufacturers plate normally inside the engine and the caravans maximum axle and gross weights loaded safely. Using you figures there is no problem.

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ok you are obviously happy with these loaded figures and happy enough to run with these weights however the two main clubs would not view your outfit as being a particularly good towing combination because they calculate the suitability of a car and caravan on the Kerweight of the towcar and the MTPLM of the caravan and do not take the laden weight of the car into the equation .

Now we are all entitled to different opinions but in this instance i and many others would prefer to follow the guidelines of the two main clubs when checking suitability, perhaps in this instance we should agree to disagree

 

 

Neil

 

OK we will agree to disagree, but you must admit, its an interesting debate.

 

 

Phil.

Light travels faster than sound, thats why some people appear bright, until you hear them speak.
Mine : Mercedes GLC 250d AMG, Lunar Clubman SB, Rockwood 5th Wheel Trailer, La Manga Spain.

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Sorry i did not see your updated post re the additional weights.

 

With respect however, i am not towing at 96%, but as i have proved 78%, ie the fully laden van is only 78% of the weight of the fully laden car.

 

 

Phil.

When i weighed my outfit before leaving for Spain in january my X-trail loaded with full tank of fuel plus loaded boot and myself + better half came in at 2039 kg (max laden weight 2050kg) and the caravan fully loaded was 1417kg which equates to 69. 5 % if i calculated the car to caravan weight ratio the way you have .

However i dont and go by the MPTLM and the kerbweight of the car and van as advised by the two main clubs but as i said each to there own

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Having towed on many occasions at 200/300% [not caravans] the percent ratio is of no interest to me. I never exceed MTPLM, I never exceed the towing limit of the towcar. As for the noseweight, I never exceed 100Kg which is the limit of the over-run braking mechanism. I suppose that make me irresponsible and dangerous. I don't think so. This argument will never be resolved.

Edited by geriatric
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Neil

 

OK we will agree to disagree, but you must admit, its an interesting debate.

 

Phil.

Hi Phil,

 

I have my own take on this but in principle I think I am with you on this one, if you take the kerb weight as stated in the handbook for the car, you are working on the lightest it could possibly be, if you then take the MPTLM of the caravan, you are working on the heaviest the caravan should be.

 

If those figures fall within 100% but preferably less i. e. 85% then you meet with the "accepted parameters" which are designed to ensure the caravan never weighs more than the car (as you say "Tail wagging dog syndrome").

 

However, if you never exceed the MPTLM of the caravan, the heavier the car over and above the kerb weight, the greater is the car to caravan weight ratio, which if both car and caravan are loaded correctly will increase stability. (Accepting such things as nose weight, axle weight, towing capacity of car etc)

 

What we must never loose track of is that the kerb weight is the kerb weight, a figure from which all things are calculated, however as I found with my car, the true kerb weight ex works with all the factory fitted options can be considerably greater than what it says in the handbook.

 

For mine the book says 1695kg, when i drove it back from the dealers I called and got it weighed - 1740kg

 

Whilst I use the 1695kg for my calculations because that is what the Police or the insurers will look at, I have the comfort of knowing that in reality I have an additional 45kg on my side before I start.

 

Steve

 

 

 

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Its got to be the actual weight figures that count. Providing you stay within the maximum weights allowed for the car axle gross and train shown on the manufacturers plate normally inside the engine and the caravans maximum axle and gross weights loaded safely. Using you figures there is no problem.

I would go with manufacturers plate as the legally defined max towing capacity,indeed some cars do not have this train weight on them and are not designed to tow at all. I asked at the HGV test station about towing weight and they agreed that the manufacturers plate is the one to go by but then stated that in the event of an accident they would look at the stability of the car and caravan combination,there you go even the Ministry think it is a grey area.

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For my two pence worth (now worth one in current climate)

85% rule is there as a guideline, surely? What matters is what you are actually weighing like the op stated.

MPTLM is a worst case heavy scenario providing the payload is fully utilised. . if your van has say a 260kg payload then thats the equivalent to 13 'Holiday' suitcases!! (..and I know how heavy my 20kg holiday case is!) Even considering the 'essential' habitation bit,I believe you would be hard pushed to hit that.

Having changed the car/van last week I was surprised what came out the van during 'changeover' but I reckon the heaviest items were tins of grub, a small cylinder hoover and the gas bottle. ..

 

So for me, no panic over hitting nearly the 95/100% mark when utilising the 'guidelines' as your outfit makes sense in reality, is within its towing limit capability and the overall manuf train weight is not exceeded then reality is better than anything.

 

Interesting debate though. .. I'm with the OP.

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