100% towing

[karl.greenfield]

I'm looking at a new twin axle van which has a MTPLM of 1690kg.

I currently tow a single axle Swift with a MTPLM of 1460kg which my BMW 520d Tourer pulls with ease (170bhp). The kerb weight of the 520 is 1675kg (includes 75kg driver and 90% fuel tank) and can tow 1800kg manufacturer approved with a 90kg nose weight.

During towing I will 95% of the time have a full car (family of four + dog!) and bikes on top.

I've been towing nearly three years with no problems and have heard that a twin axle is more stable and more likely to balance with regards nose weight than a single axle.

I would welcome any comments on this match and if anyone sees it a a real risk or would be quite comfortable with the tow?

 

[Lutz]

It is impossible to make cut and dry comment either way as this is a very grey area where you will find valid arguments both for and against. One thing is for sure, however, and that is the higher the weight ratio demands more due care and concentration when towing and driving will not be as relaxed as with a lower ratio, but there is no percentage above which any risk suddenly becomes unmanageable and there is the threat of certain disaster. For years I used to tow at around 100% and felt quite comfortable with the outfits that I had, but I can just as well understand people who prefer to have a bigger margin that allows for more relaxed driving.

I am assuming that your driving licence allows you to drive what is actually a fraction over 100%.

You mention balance in connection with a twin axle. Note that correct and adequate noseweight is just as important with a twin.

 

[John_374564913]

My only comment on this is that you stated the MTPLM is 1690kg

the kerb weight of the BMW is 1675kg which is about 99%

However I would assume you have a caravan load factor of around 300kg so it is possible you could load some of that into the car assuming you only put in 200kg it would reduce the percentage down too 94% if both my calculations are correct

I know its not much of an improvement around 5% but I would imagine it all helps

PLEASE NOTE I AM NOT AN EXPERIENCED CARAVAN PERSON SO MAYBE SOMEBODY WHO IS WILL COMMENT ON WHAT I HAVE WRITTEN

 

[Lutz]

Not 99%, John, but 101%.

 

[Garfield]

MTPLM is a theoretical number and irrelevant when towing as long as you don't actually go over it, MIRO plus payload ie the actual weight of the caravan is the relevant weight you should consider.

The difference between MIRO and MTPLM (ie the payload) varies considerably from model to model, consider the following scenarios

1600kg car, 150kg payload MIRO 1250kg MTPLM 1600kg actual weight of caravan 1400kg =87.5% but using MTPLM = 100%

Same car and payload MIRO 1450kg MTPLM 1500, actual weight of caravan 1500kg = 94% using MTPLM = 94%

ie the supposedly heavier caravan is actually the lightest

 

[Lutz]

Weight ratio, by convention, is ALWAYS a comparison between the MTPLM of the caravan and the car's kerbweight. Anything else, such as based on actual figures, is totally meaningless as it has no basis for comparison with other outfits.

The criterion for determining whether a Category B driving licence issued after 1st January 1997 covers your needs is also MTPLM versus kerbweight (again, NOT the actual weights).

If the weight ratio based on actual weights is 80%, 90% or any other value, all one can say is "so what?". One cannot deduce anything from such a figure.

 

[karl.greenfield]

Thanks for your responses. The times when I'll be using the full caravan payload (assuming I don't empty it) and reduced (or actual) kerbweight of the car will be when taking for a service once a year.

On trips out there will be +200kg in the car (family, bikes and clothes etc) with maybe 160kg at the end of the journey less fuel which in effect gives about a 92% ratio.

I passed my test back in '88 and am applicable to drive all the relevant classes I think.

 

[mcghee]

towing at 100% is not a big issue. i did it for years with various cars, and sometimes tow well in excess of 100% in the case of plant trailers and car transporting trailers.

you must be aware that the more you tow the more it alters the handling of the towing vehicle, especially on the approach to roundabouts and bends, so your braking must be done plenty in advance.

your bmw has a healthy noseweight limit of 90kgs, which should allow for good stability. i'd make sure the noseweight was always up around that figure.

your statement about twin axles is not strictly accurate though. 90kgs noseweight is 90kgs no matter how many axles you have, and under certain conditions the twin axle can exert a huge momentary noseload, and even a negative noseload, which can be very dangerous.

however, i would have no issue at all with using the outfit you describe.

 

[ProfJohnL]

Mcghee very correctly points out that the actual nose load under dynamic towing conditions can and does change quite dramatically, ven more so with a twin axle because of the interaction of the suspension on both axles.

For the same reason, the interaction of the twin suspension units do affect the nose load measurement, so it is very important you measure it using the correct method.

Car and caravan must be on level horizontal ground.

With car and caravan hitched and loaded as if ready to travel with all luggage driver and passengers, the height of the tow ball must be measured and noted from the ground. (For compliance with EU regulations it should rest between 350 and 420mm ground to the centre of the ball.)

Chock the main wheels and Unhitch the caravan, set your measurement gauge to the same height as previously measured, and lower the hitch onto it. Raise the jockey wheel and all steadies off the ground. The gauge should now read your true nose load.

Most purchased gauges do not allow you to adjusts their height, so a fairly reliable method is to use a set of bathroom scales with a broom stale cut to length with a foot to spread the load on the scales pad.

 

[HenryB1]

I think you need to think carefully why you are looking at a twin axle van. There are disadvantages, higher weight, higher servicing costs, double the number of tyres to replace. Also when fitting wheel clamps, particularly the latest Alko through the wheel clamps you will probably land up having to jack up one of the wheels to aline the clamp. Many insurance companies now insist that twin axle vans have have clamps applied when van is left together with an alarm. You have a dog as I do. I cannot claim the discount for having an alarm and tracker fitted as we occasionally leave dogs for a short while in the van so at that time I cannot activate the alarm. If my insurance company insisted that alarm was set every time I left caravan when on a site this would be a problem. I have towed twin axle trailers, although not caravans, and they are much harder to manover in tight spaces. I also have met two people during my many years caravanning who have rolled twins axle vans because they believed they were more stable and towed vans that were too heavy for their car.

 

[Zafiral]

As you are intending on towing with the car laden ensure that the gross train weight is the sum of the gross vehicle weight and the max tow weight. Some manufacturers will not allow you to tow their max tow weight when the car is laden.

Also the max tow weight could be based on a trailer rather than a caravan which will have less wind resistance. The bikes will increase wind resistance too, so even if you ate within the gross train weight the strain on the running gear will be increased.

 

[jacky3]

hi,

forgive my ignorance here,but!!!!.................am i right in thinking that a dealer should not be selling a caravan to anybody whos cars kerbweight is less than the MTPLM OF THE CARAVAN......enlighten me????

 

[STEPHEN_374226156]

hi,

forgive my ignorance here,but!!!!.................am i right in thinking that a dealer should not be selling a caravan to anybody whos cars kerbweight is less than the MTPLM OF THE CARAVAN......enlighten me????

Wrong it is nothing to do with any vendor providing your tow car allows the weight and your driving license covers you

 

[Parksy]

It's the drivers responsibility to ensure that an outfit is legal and safe.

The dealer can and should offer advice but the legal responsibility rests with the driver and nobody else.

 

[Zafiral]

Klarky, not withstanding the fact is is not the vendors responsibility to ensure an out fit is legal, there is no legal reason why you can't tow at above 100% unless you passed your test after 1997 so why should a dealer refuse to sell a caravan?

 

[paul_5132583]

I have just recently got back into caravanning, after a break of three years, my previous caravan was a twin axle Swift Conqueror 640 saloon Max weight 1500kg from memeory, towed by a Vw Touran Kerb weight with me in it 1725kg's . Which was around the 87% weight of car to caravan ratio. I towed this for two years, and took it to Spain twice.I now tow a Swift Challenger 530se which weighs in at 1300kg's fully laden,Still use the Touran.

My observations are as follows.The first outfit always felt stable, and I never experienced any snaking etc. However it was always at the back of my mind that this was a borderline tow in my mind, you will find many references to towing ratio's here and to be honest I felt that I was always kidding my self that it was'nt really relevant.

On a down hill run, with a cross wind, and an overtaking coach or panel van, slight road camber, the ratio will be very much at the forefront of your thoughts.

I now tow at 75% and although the outfit dose'nt feel any different, the peace of mind that the ratio is stacked in my favour makes me feel better.

This results in relaxed towing. The twin axle was also a ****** to move around, whether you jacked up the front or not.

Personally I will not go back to Twin axles.

Paul.

 

[jacky3]

Klarky, not withstanding the fact is is not the vendors responsibility to ensure an out fit is legal, there is no legal reason why you can't tow at above 100% unless you passed your test after 1997 so why should a dealer refuse to sell a caravan?

so why do they use, and pay to do so,caravan and car outfit matching sites to check the customers car details, if they have no legal obligation on selling an overweight caravan that is legally no good and unlawful to a customer???????????????????.

and why do most reputable dealers refuse to sell a customer a caravan when a mismatch occurs(mismatch being over the 100% of said cars kerbweght)

 

[Lutz]

Klarky, not withstanding the fact is is not the vendors responsibility to ensure an out fit is legal, there is no legal reason why you can't tow at above 100% unless you passed your test after 1997 so why should a dealer refuse to sell a caravan?

I do not know of any dealer selling a (new) caravan that is legally no good or unlawful. It can only become illegal when hitched up to the car, but that's none of the dealer's business.

Unless you passed your driving test after 1st January 1997 and only hold a Category B licence, there is nothing illegal with a weight ratio being over 100%. Whether it is to be recommended is quite another story.

 

[Lutz]

I have just recently got back into caravanning, after a break of three years, my previous caravan was a twin axle Swift Conqueror 640 saloon Max weight 1500kg from memeory, towed by a Vw Touran Kerb weight with me in it 1725kg's . Which was around the 87% weight of car to caravan ratio. I towed this for two years, and took it to Spain twice.I now tow a Swift Challenger 530se which weighs in at 1300kg's fully laden,Still use the Touran.

My observations are as follows.The first outfit always felt stable, and I never experienced any snaking etc. However it was always at the back of my mind that this was a borderline tow in my mind, you will find many references to towing ratio's here and to be honest I felt that I was always kidding my self that it was'nt really relevant.

On a down hill run, with a cross wind, and an overtaking coach or panel van, slight road camber, the ratio will be very much at the forefront of your thoughts.

I now tow at 75% and although the outfit dose'nt feel any different, the peace of mind that the ratio is stacked in my favour makes me feel better.

This results in relaxed towing. The twin axle was also a ****** to move around, whether you jacked up the front or not.

Personally I will not go back to Twin axles.

Paul.

An 87% weight ratio can hardly be described as a borderline tow, at least not as a generalisation.

 

[jacky3]

I do not know of any dealer selling a (new) caravan that is legally no good or unlawful. It can only become illegal when hitched up to the car, but that's none of the dealer's business.

Unless you passed your driving test after 1st January 1997 and only hold a Category B licence, there is nothing illegal with a weight ratio being over 100%. Whether it is to be recommended is quite another story.

so what you are saying, caravan dealers have and do waste thousands of pounds checking sites like towsure to check customers tow car compatability when buying a caravan from them.and whats the point of asking a customer what towcar he has when enquiring on buying a caravan.why do this when its of no consequence to them whether the van is over 100% or not,doesn't make sense.and most reputable caravan dealers most certainly do refuse to sell vans that are more than 100% of the cars kerbweight and thats fact.

 

[Zafiral]

Klarky, the outfit matching sits also carry a wealth of details about cars legal weights for information use, especially for cars no longer on sale is useful, I would be wary of a dealer who did nothave access to this information, but they are not policemen.

As Lutz says, no caravan is illegal, perhaps it's usage is incorrect. Where is the difference in a car manufacturer selling a car capable of 140 mph when the limit is 70?

I am all for a dealer giving information, but for them not to sell a caravan that is over 100% ratio when the match is perfectly legal (especially if the van is nearly empty at the time of sale) is going too far. They can recommend suitability and refuse to physically hitch up, but it would annoy me for them to go beyond that, to me by making me aware of the situation would cover their liability.

 

[Lutz]

I do not know of any dealer selling a (new) caravan that is legally no good or unlawful. It can only become illegal when hitched up to the car, but that's none of the dealer's business.

Unless you passed your driving test after 1st January 1997 and only hold a Category B licence, there is nothing illegal with a weight ratio being over 100%. Whether it is to be recommended is quite another story.

Any matching service that the dealer may offer is purely a guideline for information only. Many of the matching websites have data that is not 100% correct and cannot, therefore, be relied upon without reservation, either. Any result that they come up with will not have any legal significance.

 

[Lutz]

One should also not forget that none of the matching websites can be relied on completely for absolutely accurate information. Any result that they come up with will therefore serve as a guideline only and not carry any legal weight.

 

[jacky3]

Any matching service that the dealer may offer is purely a guideline for information only. Many of the matching websites have data that is not 100% correct and cannot, therefore, be relied upon without reservation, either. Any result that they come up with will not have any legal significance.

agree,but why use it in the first place if its of no significance to them in selling a van?????

 

[Lutz]

Any matching service that the dealer may offer is purely a guideline for information only. Many of the matching websites have data that is not 100% correct and cannot, therefore, be relied upon without reservation, either. Any result that they come up with will not have any legal significance.

You're asking me? That is a question that you must address to the dealers using these matching websites.