Missing MTPLM

[colin-yorkshire1]

hi Roger, And there in your last statment you have hit the nail squarely on the head, it's the payload calculation that needs to be addressed, why can't the effective user payload of a 2berth be the same as a 4 if the owner requires it.
it is just that simple.

regarding the 85% recommendation while it is true that one could just ignore it (many of us seasoned caravanners do just that),
there is absolutely no doubt that newbies would take account of it when calculating the effective tow weights of their car given that every caravan organisation and press (inc PC magazine) take every oppotunity to mention it, so much so that it is often wrongly refered to as a "rule" as you well know, allthough the method of calculation differs from one source to another the basic premiss is 85% of the cars kerbweight ignoring the recomendation of any particular vehicle manufacturer,
it is therefore obvious that any caravan manufacturer seeking inroads into this market would also take account of it and reduce the MTPLM's of vans in this sector to comply, and as cars are effectively getting lighter with smaller engines, one way to do it is to downgrade the user payloads even further towards the MIRO,
as you said in the 80's vans had huge user payloads in the region of 4 to 5cwt (200/250kg) but had little in the way of equipment.
in a small caravan today you would be lucky to get 100kg as MIRO's have got bigger with all the equipment on board.

so it is not true that van makers would not see the link between the recommendation and the effective MTPLM reductions in their model weights it has to be a factor.

 

[Lutz]

as you said in the 80's vans had huge user payloads in the region of 4 to 5cwt (200/250kg) but had little in the way of equipment.
in a small caravan today you would be lucky to get 100kg as MIRO's have got bigger with all the equipment on board.

With its optionally uprated MTPLM my 2008 caravan has over 400kg payload.

 

[otherclive]

The user payload calculation hasn't changed - it's still based on the same multiple of the caravans interior length in metres plus another multiple of the number of berths. The old method of quoting payloads as essential items plus user payload has simply changed by including essential items in the MIRO, giving an impression of heavier caravans with an impression of lower payloads - but in reality nothing changed.
It is true of course that caravans have been getting heavier, year on year, sincle the early '80s. back then a mid-range 5-berth was 650kg net and 800kg gross - I guess they're double that or more, in terms of net weight.

roger it would be nice if what you say is true but its not. Looking at one maker their total payload for a 4 berth in their range is 160kg yet the interior lengths and external lengths vary by more than .7m. Another maker has a higher payload in the basic model than for its top spec, yet the top spec internal lengthy is greater. Also haven't headroom and width increased which will increase weight. But your formula doesn't make any allowance for this. Increased insulation too will further add weight again not allowed for by the customer, and I suggest in many cases not used as many don't go away in winter.

 

[RogerL]

as you said in the 80's vans had huge user payloads in the region of 4 to 5cwt (200/250kg) but had little in the way of equipment.
in a small caravan today you would be lucky to get 100kg as MIRO's have got bigger with all the equipment on board.

I didn't say that - in the '80s a 5-berth caravan got a 150kg payload but 30kg of that was 2x 7kg butane cylinders, leaving 120kg for everything else - it was also true in the '80s that the net weight variation of 5% could eat into the payload by as much as 32kg in the example I quoted leaving just 88kg user payload for 5 people. Net weight was defined in a different way to MIRO.
Currently, the MIRO variation of 5% is included in the quoted MIRO - I'm looking at buying a 4-berth caravan which has a user payload of 154kg, the minimum for it's length and berths.
So I think that usable payloads have also doubled in the 3 decades my example covered.

 

[RogerL]

The user payload calculation hasn't changed - it's still based on the same multiple of the caravans interior length in metres plus another multiple of the number of berths. The old method of quoting payloads as essential items plus user payload has simply changed by including essential items in the MIRO, giving an impression of heavier caravans with an impression of lower payloads - but in reality nothing changed.
It is true of course that caravans have been getting heavier, year on year, sincle the early '80s. back then a mid-range 5-berth was 650kg net and 800kg gross - I guess they're double that or more, in terms of net weight.

roger it would be nice if what you say is true but its not. Looking at one maker their total payload for a 4 berth in their range is 160kg yet the interior lengths and external lengths vary by more than .7m. Another maker has a higher payload in the basic model than for its top spec, yet the top spec internal lengthy is greater. Also haven't headroom and width increased which will increase weight. But your formula doesn't make any allowance for this. Increased insulation too will further add weight again not allowed for by the customer, and I suggest in many cases not used as many don't go away in winter.

It's not MY formula - it's the formula for the minimum required to meet the EN standard relating to touring caravans.

There hasn't been any increase in insulation, it's still the same thickness - previously UK manufacturers never bothered testing below grade 2 so could only claim grade 2 - now they test down to grade 3 and they pass

 

[Lutz]

I didn't say that - in the '80s a 5-berth caravan got a 150kg payload but 30kg of that was 2x 7kg butane cylinders, leaving 120kg for everything else - it was also true in the '80s that the net weight variation of 5% could eat into the payload by as much as 32kg in the example I quoted leaving just 88kg user payload for 5 people. Net weight was defined in a different way to MIRO.
Currently, the MIRO variation of 5% is included in the quoted MIRO - I'm looking at buying a 4-berth caravan which has a user payload of 154kg, the minimum for it's length and berths.

Until about last year, MIRO was only defined for motor vehicles, not for caravans. Previous to that, MIRO was already a common term for quite some time, but it wasn't defined and, in general, it was interpreted by each manufacturer as he saw fit.

 

[RogerL]

Until about last year, MIRO was only defined for motor vehicles, not for caravans. Previous to that, MIRO was already a common term for quite some time, but it wasn't defined and, in general, it was interpreted by each manufacturer as he saw fit.

Depends what you mean by "defined".
All caravans sold in Europe complied with the relevant EN standard - but additionally the UK's NCC issued a code of practice which included the EN standard requirement and went further than that by including a definition of MIRO which, until last year, excluded gas, battery, water and waste - all mainstream UK caravan manufacturers are members of the NCC and so used the NCC code of practice. So for mainstream UK caravans, MIRO has been "defined" for a long time but the "definition" changed last year.

 

[Lutz]

The EN standard that you refer to didn't come into being until 2008.
I must correct you that MIRO has been "defined" for a long time. Until the EN standard was implemented, every caravan manufacturer had his own definition of unladen weight.

 

[RogerL]

The EN standard that you refer to didn't come into being until 2008.
I must correct you that MIRO has been "defined" for a long time. Until the EN standard was implemented, every caravan manufacturer had his own definition of unladen weight.

Lutz - I'm refering to EN 1645, which was in place in the late '90s, although it was revised for the 2010 model year.
All the UK mainstream caravan makers, ie Bailey, Coachman, Elddis, Lunar and Swift are members of the NCC and adopt the NCC Code of Practice - there is no variation of defintion by manufacturer among the UK mainstream.
The NCC Code of Practice, already in place in the late '90s incorporated EN 1645-1, EN 1645-2 specifically relating to payloads, EN1648-1 and EN721.
Of course other manufacturers could/can sell caravans in the UK even if they didn't comply with the NCC Code of Practice as long as they did/do comply with the relevant EN standards.
Before 2010, European manufacturers may have varied their definition of MIRO but UK manufacturers were consistent.
Other organisations are allowed to define terms, other than in EN standards.

 

[Lutz]

EN 1645-1, as first published in 1998, is entitled "Leisure accommodation vehicles. Caravans. Habitation requirements relating to health and safety" and hence has nothing to do with the definition of MIRO.
MIRO was first defined in EN 1645-2 "Leisure accommodation vehicles. Caravans. User payload" and that was published in 2008. If UK manufacturers had a common understanding prior to that date it was for the unladen weight, not MIRO. The same applies to the definition of the kerbweight of motor vehicles versus their MIRO.

Other organisations are allowed to define terms, other than in EN standards.

Yes, of course, but in order to avoid confusion, they cannot use the same term as in the EN standard and then define it in a different way.

 

[RogerL]

My 2001 caravan is approved by the then current NCC Code of Practice and the accompanying documentation specifies EN 1645 and specifically refers to EN 1645-1 and EN 1645-2.
I believe that both EN 1645-1 and EN 1645-2 were in place in 1998, but certainly by 2001. I think you're referring to the revision of EN 1645-2 in 2008 and ignoring the fact that it did exist before then.
I can't speak about European manufacturers but EN 1645-2 was in place and being complied with by UK mainstream manufacturers from about 1998.
EC regulations don't ban the use of terms used in EN standards - such a ban would be preposterous.

 

[Lutz]

I apologise. Yes, I have rechecked and learned that EN 1645-2 was indeed
first published in 1998 but later replaced by the 2008 version. I don't
know what the differences between the two editions are. However, one
thing is certain; the 1998 version was not implemented by all
Continental manufacturers. They too, continued to use the term unladen weight with its own interpretation until, with the introduction of whole vehicle
type approval, they were they forced to adopt a common standard, and whole
vehicle type approval didn't come into force until well after 1998, even on the Continent.

EC regulations don't ban the use of terms used in EN standards - such a ban would be preposterous.

It would be equally absurd to have one term with two conflicting definitions.

 

[RogerL]

It would be equally absurd to have one term with two conflicting definitions.

Then we best hadn't discuss the definition of "kerbside weight" in the UK - it has at least 2 definitions as well as a different name which means the same !!!

 

[Lutz]

I am only aware of one "definition" if you can call it that. I deliberately use parentheses because UK law doesn't recognise the term 'kerbweight' so one can argue that there is no binding definition, only an industry agreement by convention. This was the weight of the unladen vehicle (which is the legal term) plus all fluids, such as oil, coolant, brake fluid, and a full fuel tank. To my knowledge this definition has never changed.
However, what we now have is MIRO, (also referred to as Mass in Service in the V5c certificate) which is basically the same as kerbweight, but with the tank only 90% full and a 75kg allowance for the driver and sundry specified items.
I know some sources still use the term kerbweight when they are actually referring to MIRO, but this is incorrect as it leads to confusion. Kerbweight is not the same as MIRO.

 

[chrisbee1]

I'm now beginning to question the purpose of the NCC certificate. Just to add to the confusion, the original NCC certificate gave a MTPLM of 1400 kgs which was shown on the body plate so the certificate and the plate matched, now they differ by 80 kgs. The "under gear type approval number" has also changed, quite how a payment does this I don't know. Strangest of all, the new certificate shows the external length to be 146 mm shorter. Better get the hacksaw out.

Just as an aside, were the caravan to be drastically modified, say converted to a flatbed trailer, would the MTPLM of 1420kgs be the limit or the chassis limit of 1500kgs?

 

[colin-yorkshire1]

I would think 1500kg because it would no longer be a caravan and therefore the van makers plate would be obsolete, the problem however would be getting type approval for the modified trailer unless done proffesionally,

 

[Lutz]

As caravan type approval becomes universal, provisions will surely be in place for single vehicle approval, as is already the case for kit cars, etc. The same will apply to vans rebuilt privately as motor homes.

 

[colin-yorkshire1]

As caravan type approval becomes universal, provisions will surely be in place for single vehicle approval, as is already the case for kit cars, etc. The same will apply to vans rebuilt privately as motor homes.

agreed but the type approval with a kit car comes with the kit as the manufacturer of the kit has to do all the design work, the home builder has then to have it tested to make sure it has been built to spefiication, this is not the case with trailers not yet anyway.
but its going that way in future nothing will be home built, thats the point of the legistlation.

 

[Lutz]

I wouldn't see things quite as bleak, Colin. Over here in Germany, where for years, all vehicles have to be type approved and all technical changes involve a retest unless the modification itself has been homologated, there is still the possibility of registering a vehicle which has been completely home built. You just take it to the equivalent of the MOT together with all relevant paperwork (such as data sheets for material used, for example) and they use their engineering judgment in assessing the finished product.

 

[RogerL]

My take on this - new caravans now have to meet EU-wide Whole Vehicle Type Approval regulations - one-off hand-built trailers only have to meet the Construction & Use Regulations of the country it's used in. As UK trailers aren't required to be registered, then that's all that's required here.
In the case of removing a caravan body to use as a basis for a flat-bed trailer, the Alko/BPW parts left will still comply with UK C&U Regs as they did with the body on, but lighting will have to be fitted and the trailer bed will need to meet the C&U Regs as well.

 

[colin-yorkshire1]

yes Lutz I see where you are comming from and considering Germany tends to lead the way in such matters, maybe thats the way it will go.
but at present here in the UK we have a 80% rule, and that is any vehicle re-manufactured (home built) must contain 80% or more of the original donor car, or it has to be re registed on a Q plate (built from parts). the more type approval legistlation rolls out the harder it is to obtain a Q plate, a friend of mine built a trike using parts from a bmw bike home made chasis and a car engine, but could not get it registered as a motor vehicle. however no legistlation "as such" was required for trailers, you could build one from scratch using indispension units, and tow it anywhere, with all the reams of type approval weight restrictions and such I cannot see how in the future this would be possible