Payload

[Lonesome-Whizkid]

Yeah, using a spreadsheet is a good way of only having to weigh something once and keeping a note of it. But im confused again about your 61kg allowance, Is that part of your MIRO or are they saying that your payload is 61kg more than what is documented,? affecting the true figure of your MTPLM?? Oh i think i know what you mean, when the caravan rolls off the warehouse before they set the MIRO they take into account what youve listed there? i.e. fresh water, toilet water, gas allowance, water heating, essential fluids? You mentioned that the MIRO has a new way of being set, Is that a recent thing? And am i correct or wrong about my assumption regarding your 61kg allowance? I guess it doesn't matter if I'm confusing myself or anyone else as long as i dont breach that all important MTPLM. I was reading about payload being the cause of noseweight and how to properly pack your caravan, and that if its improperly packed it could suppress your rear suspention of your towing vehicle which in turn would affect your driving breaking steering abilities and also endanger others, So im glad ive got a few good books and the assistance of this forum to help also.

 

[ProfJohnL]

OK Whiz,

Its very laudable to try and understand all the details about towing, but I think you may be beginning to suffering from information overload!

As I stated above its been a few years since the change in the way MIRO is established, and it does leave considerable confusion.

When a caravan leaves the assembly plant it will have an "Ex Works Weight" (This is rarely quoted these days)

To make it capable of being used as a caravan it needs a few things like a gas cylinder, fresh water and hook up cable (List from the NCC Site) These are the Essential Habitation Equipment, and as you find, what the list actually contains varies from model to model. - But each manufacture should be able to tell what their list includes and how much they believe it will weigh.

In theory By adding the Ex Works Weight and the EHE weights you get to the Mass In Running Order or MIRO.

Now this is a fudge, because the weight of the EHE items could be very different, if you choose not to take some of the items, for example in the EHE list Xtrailman quoted, it includes 20.7Kg and 7.6kg for freshwater and heated water, Many caravanners empty their water systems when towing. So that's 30kg approx variance, Many caravanserai's do not take the largest bottles of gas, so there is a another saving, but they have missed out the battery, which is often needed to make some of the habitation equipment function, So the MIRO figure is a bit of joke.

It's safest to go back the the ExWorks weight, and then assume you need to account for everything added over and above the ex works weight.

Regardless of which way you do it you must always make sure the whole caravan does not exceed the MTPLM.

NOSE WEIGHT.
The nose weight of a caravan is created by the position of the caravans centre of mass (CoM or Centre of Gravity CoG) in relation to its main axle. If the CoM is forward of the main axle, then there will be a positive nose weight. And the size of the nose weight is determined by the mass of the caravan and how far forward of the axle the CoM is. So its not true to say the Payload causes the nose weight, but it does affect it, and if you need to adjust the nose weight you do so by repositioning elements of the payload.

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[Lonesome-Whizkid]

I'm starting to understand now. So what your really saying is if a caravan is advertised with a payload of say 200kg. With a bit of smart thinking you could increase it slighly to 230kg taking note that if you take it to a weighbridge once packed up and your not over your MTPLM then your on easy street? Is that right?

 

[ProfJohnL]

I would hesitate to call it "Easy Street" :S but in essence what you write is in my view correct .

 

[colin-yorkshire]

hi Lonesome-Whizkid, I think you are nearly there with your understanding B) you remember your first post when I said caravanning was complex, I think by now you are getting the drift of what I meant :woohoo: I do not wish to confused you further but would add that sometimes life can be made easier by thinking outside the box.