MTPLM dilema

[Newtonian]

Hey all, so we are about 6 months into caravaning and have a Adria Altea 542dk which has a mro of 1120 and MTPLM of 1300, but the van has a number of after market things so we have always been cautious to not put a lot in the van while towing. Today I got it weighed pretty empty (apart from hookup cable, wheel lock, water and waste bins) 1260!!!

How can I make the van lighter, I'm assuming motor mover must be 50kg, but the solar panel must be fairly light?

I'll weigh everything I had in the van over the weekend but I can't believe the shipping weight was as low as 1120

 

[IanB1485]

The spare wheel (17kg) can kept in the car whilst travelling and alko underbody wheel carrier (13kg) can IMO be thrown away, keep in safe place until selling the caravan.

 

[Newtonian]

The spare wheel (17kg) can kept in the car whilst travelling and alko underbody wheel carrier (13kg) can IMO be thrown away, keep in safe place until selling the caravan.

The spare wheel wasn't in the caravan when weighing! And we don't have under body carrier either it's 2012 model so usually goes in the front

Unless you know something I don't I want to go look now

 

[otherclive]

I had a French caravan which was stated to have ex works of 750kg and MTPLM of 1000kg. I weighed everything very carefully and trotted off to Brecon for a maiden voyage. Just outside of Brecon is a public weighbridge so I called in to have it weighed. Shock and horror it weighed nearly 1240kg. Spoilt the weekend I can say. Fortunately I had fitted new Kenda trailer specific tyres that were sufficient for the overload. When I got home I stripped out everything apart from one 6kg gas cylinder and the battery and took it to a 5 tonne weighbridge at Longleat. Sure enough it weighed in around 960kg, which left me 40 kg payload.

It transpired that the caravan was produced following the financial crash of 2008. The French maker had been updating the model with additional fittings, a stronger pop top roof etc. In some respects it was a hybrid. Plus the importer had added features attractive to British buyers, like heater, shower, hot water heater, fridge, mini cooker etc. The first owner had added an automated mover. All this had eaten into the payload, so I px’d the caravan, but in its defence it towed beautifully 😱


MRO s can vary by 3-5% which is not insignificant when you have low payloads. Don’t underestimate the solar panel weight measure it and try a find makers specification for weight details. Same with mover.

 

[ProfJohnL]

Sadly you are experiencing some of the realities of caravanning and how tight load margins can be.

This bit may be seen by some a rather contentious by some commenters here on PCF. For some unexplained reason caravans sold in the UK that have been accepted by the NCC often have a label by the entrance door that implies the caravan as a MTPLM which less than statutory MTPLM defined by the EU regulations. The EU MTPLM should be on a plate inside the front locker or attached to the AFrame. You may (or may not depending on the model of caravan) discover your real legal MTPLM is greater than you think.

Many UK manufacturers ( and I don't know about foreign makers) may be prepared to offer an MTPLM upgrade from the artificially low value to be closer or match the official value, and cant help feeling this is money for nothing as there is no mechanical change made to the caravan.

 

[GUMPY]

I have just had mine on the weighbridge, again, it was 1420kg, hitch was 82kg so pretty close to the 1500kg mtplm. This included bedding, cutlery, crockery, TV, hook up cable and water plus waste containers.
The rest, clothes, food, awning, chairs, and all the other paraphernalia we take travels in the car. Apart from clothes it's all packaged or in plastic boxes so easy to pack and unpack
I guess that if you have the room in the car you will be doing the same.
Its a shame that manufacturers don't use decent axle weights (mine is 1500kg) a 1750kg axle would make the van so much easier to use.
Just to add to keep the weight down I have a LifePo4 battery, 15kg saved, and Flogas lite gas bottle another 5kg saved.

 

[Newtonian]

Sadly you are experiencing some of the realities of caravanning and how tight load margins can be.

This bit may be seen by some a rather contentious by some commenters here on PCF. For some unexplained reason caravans sold in the UK that have been accepted by the NCC often have a label by the entrance door that implies the caravan as a MTPLM which less than statutory MTPLM defined by the EU regulations. The EU MTPLM should be on a plate inside the front locker or attached to the AFrame. You may (or may not depending on the model of caravan) discover your real legal MTPLM is greater than you think.

Many UK manufacturers ( and I don't know about foreign makers) may be prepared to offer an MTPLM upgrade from the artificially low value to be closer or match the official value, and cant help feeling this is money for nothing as there is no mechanical change made to the caravan.

The plate says 1300 so that's what I'll use. I have since realised there are other things hidden in the van I forgot to remove. Microwave, mini awning etc. so I'll be weighing everything this weekend and then probably removing the motor mover...it's 12 years old

 

[Lutz]

MRO s can vary by 3-5% which is not insignificant when you have low payloads. Don’t underestimate the solar panel weight measure it and try a find makers specification for weight details. Same with mover.

Don't be misled into thinking that MIRO is the unladen or ex works weight of your caravan. It is not. It is the weight of the caravan that the manufacturer submitted for type approval, and that could have had a different spec. The actual weight could therefore differ by more than 3-5% from the stated MIRO. There was a case on another forum a little while ago where the ex works weight of somebody's caravan was more than 230kg heavier than the quoted MIRO because it had been specified with numerous factory fitted optional extras. I would say that was exceptional, but it does show what can happen.

 

[Woodentop]

Here's a thought for you. When you load the van to, say, about 1440kg when it has an MTPLM of 1450kg (which is usually the rating of the axle), what happens to the extra load when you/family/guests are sitting inside (during a rain storm.) The payload then would be way over the max axle load. I realise it makes no difference from a legal standpoint as it is static, but from an engineering view its a very different matter.

 

[GUMPY]

For me MIRO is some number that is totally irrelevant for day to day operations.
MTPLM is the only one that counts for anything.
Load stuff in the van, weigh it and add or subtract stuff until you have it right.
My first weighbridge venture was best part of 100kg over what it should be. The van weighed well over 1500kg plus the hitch weight.
When I finally sell the van and have emptied all my kit and kaboodle from it I will have one last visit to the weighbridge just to see how far away from the published MIRO the actual unladen weight is.

 

[GUMPY]

Here's a thought for you. When you load the van to, say, about 1440kg when it has an MTPLM of 1450kg (which is usually the rating of the axle), what happens to the extra load when you/family/guests are sitting inside (during a rain storm.) The payload then would be way over the max axle load. I realise it makes no difference from a legal standpoint as it is static, but from an engineering view its a very different matter.

The extra weight is taken by the steadies 🤔

 

[Newtonian]

Here's a thought for you. When you load the van to, say, about 1440kg when it has an MTPLM of 1450kg (which is usually the rating of the axle), what happens to the extra load when you/family/guests are sitting inside (during a rain storm.) The payload then would be way over the max axle load. I realise it makes no difference from a legal standpoint as it is static, but from an engineering view its a very different matter.

I'm confused by your comments, how can a 6 berth caravan only have a mro of 1120 and mtplm of 1300 giving only 180kg of capacity. One person is about 80kg so two adults and 4 kids would leave no room for anything else surely

 

[Lutz]

Here's a thought for you. When you load the van to, say, about 1440kg when it has an MTPLM of 1450kg (which is usually the rating of the axle), what happens to the extra load when you/family/guests are sitting inside (during a rain storm.) The payload then would be way over the max axle load. I realise it makes no difference from a legal standpoint as it is static, but from an engineering view its a very different matter.

When you are pitched the caravan is static. On the other hand, the MTPLM has to take dynamic conditions into account and instantaneous actual loads under dynamic condtions can be many times anything that may be encountered when static.

 

[Lutz]

I'm confused by your comments, how can a 6 berth caravan only have a mro of 1120 and mtplm of 1300 giving only 180kg of capacity. One person is about 80kg so two adults and 4 kids would leave no room for anything else surely

The NCC formula for payload provides 10 kg per berth, 10kg per metre body length plus 50kg to take cooking equipment, plates and leisure battery into account. On that basis, a 6 berth caravan with a declared payload of 180 kg would have a body length of 7m, which doesn't sound unrealistic. The actual weight of the persons in the caravan is irrelevant, as they don't travel inside the caravan while it's being towed.

 

[trevormonty]

I have just had mine on the weighbridge, again, it was 1420kg, hitch was 82kg so pretty close to the 1500kg mtplm. This included bedding, cutlery, crockery, TV, hook up cable and water plus waste containers.
The rest, clothes, food, awning, chairs, and all the other paraphernalia we take travels in the car. Apart from clothes it's all packaged or in plastic boxes so easy to pack and unpack
I guess that if you have the room in the car you will be doing the same.
Its a shame that manufacturers don't use decent axle weights (mine is 1500kg) a 1750kg axle would make the van so much easier to use.
Just to add to keep the weight down I have a LifePo4 battery, 15kg saved, and Flogas lite gas bottle another 5kg saved.

I fitted anderson connectors to my Lifep04 so it only takes second to disconnect and transport in car. Switched to 2 smaller gas bottles, one of which is in roofbox.
Drain HW cylinder that is another 10-15kg saving for most van.

Previous owner replaced factory 5L 5kg HW cylinder with 20l 18kg(empty) one. The 250W solar panel and controller probably counts for 20kg .
I've isolation valves on HW cylinder as we rarely use so don't need to drain it every time. Also saves lot of time, thats quite while to prime water system if tank needs filling.

 

[Lutz]

I fitted anderson connectors to my Lifep04 so it only takes second to disconnect and transport in car. Switched to 2 smaller gas bottles, one of which is in roofbox.

A gas bottle in a roofbox is hardly a safe place to transport it

 

[Newtonian]

The NCC formula for payload provides 10 kg per berth, 10kg per metre body length plus 50kg to take cooking equipment, plates and leisure battery into account. On that basis, a 6 berth caravan with a declared payload of 180 kg would have a body length of 7m, which doesn't sound unrealistic. The actual weight of the persons in the caravan is irrelevant, as they don't travel inside the caravan while it's being towed.

Ok so mtplm is only when towed and the engineers accept that the van will exceed mtplm when static.

Still don't get if I load a van up to 1300kg and the. We all live in the van with 4 people that could be 240 extra kg?

 

[Lutz]

Ok so mtplm is only when towed and the engineers accept that the van will exceed mtplm when static.

Still don't get if I load a van up to 1300kg and the. We all live in the van with 4 people that could be 240 extra kg?

240kg extra is still a lot less than the maximum instantaneous dynamic load that the caravan will be subjected to while it's being towed. I wouldn't be surprised if the peak dynamic load would be in the order of 5000kg or even more if the road conditions are bad,