Weight upgrade

[Derek Uzzell]

As mentioned on Page 1 of this thread, Steve’s Dethleffs model of motorhome was available built on a Ducato ‘heavy’ (Maxi) chassis with a MTPLM of 4250kg that would have provided a significantly increased payload, but that’s academic in Steve’s case as his vehicle has a Ducato ‘light’ chassis.

 

As Laurence touches on, Steve’s motorhome will have two Certificates of Conformity (CofCs) - a Fiat one and a Dethleffs one, with the latter taking precedence. (If the motorhome had been built on an AL-KO chassis it’s to be expected that it would have 3 CofCs - Fiat, AL-KO and Dethleffs).

 

As has been commented on in the past, the UK’s DVLA and DVSA seem pretty laid back when it comes to allowing motorhome MTPLM and axle-load weight modifications, and (other than changing data on the V5C document) do not require CofC alterations. An additional ‘data-plate’ or ’sticker’ showing the revised weight data appears to be enough and JR Consultancy has provided Steve with the latter. Presumably a ‘sticker’ would be acceptable to non-UK police.

[Brian Kirby]

Laurence - 2018-11-04 6:56 PM.......................It did concern me to read that you were driving with a full tank of water. This is highly inadvisable and your manual probably advises no more than about 20 litres when travelling. Not only does it add unnecessary weight, but depending on the position of the tank and how much is in the tank, you might be generating unnecessary and unwelcome sideways forces when cornering. Maybe I'm being overcautious, but all manufacturers (and insurers) advise against this and its just not worth it.

 

Regards,

I think you are being over cautious, Laurence, but would not wish to try to persuade you into being otherwise. :-)

 

However, my understanding of the reason the manufacturers advise travelling with only 20 litres of water has little to do with safety, but a lot to do with payload. If a typical van has a fresh water tank of about 100 litres capacity, and the manufacturer advises driving with only 20 litres on board, he can justly claim his van provides 80kg more payload than if he gives no such advice. With many 3,500kg vans, were that 80 kg to be deducted from the manufacturer's claimed payload, what remained would be judged unworkable. Even if the remaining payload were not in that "just adequate" category, remaining payload is still 80kg more generous than would otherwise be the case.

 

I am not aware that insurers have commented on this issue (my own has not), and wonder if others have been warned by their insurer not to exceed 20 litres fresh water when driving.

 

I'm also somewhat sceptical as to how the owner is expected to know that the fresh water content of his tank does not exceed 20 litres. I appreciate that many vans have a two position drain valve for the fresh water tank, that is supposed to retain just 20 litres, but since the actual content of the tank will vary depending on how level the van is standing when dumping the excess, and on how accurately the content has been calibrated, I think the resulting "20 litres" can only be an approximation.

 

I have not followed this 20 litre advice, and have invariably started our trips with a full tank, only replenishing when the level falls by 50% (as indicated by the control panel), and have not noted any change in the handling of any of our vans as a consequence. There is a difference between driving the vans when empty and when at their normal "working" weight, but that is due to the extra 650kg of "stuff" that is loaded into the empty van. I have not been able to detect any surge effects from the tank, and would in any case expect these to become more apparent as the water level falls below full. After all, with the tank full there is nowhere much for the water to surge to while, as the water level decreases, there is on the one hand more space for the water to surge into, but on the other hand, less water, and hence weight, doing the surging. In practical terms, I think the one merely cancels out the other.

 

I would add that we have covered about 74,500 miles around Europe, in 4 different vans, generally not on motorways, and have travelled our share of upland and mountain roads, with their numerous bends and hairpins, where one might expect any such adverse driving characteristics to be apparent. I accept that all vans are different, so my experience may well not translate for everyone, but I don't think the wheels would come off were you to drive with your tank filled - providing you stay within all your weight limits and have appropriately inflated tyres.

[Laurence]

Brian,

 

I bow to your experience. I haven't counted the miles we have driven over 35 years and having twice lived on the continent.

 

Each to their own of course, but I certainly wouldn't advise anyone to ignore their manufacturers recommendations without careful thought. I have over 1000kg of loading weight, and you obviously have a large margin as well, but many vans have quite small margins; people do not weigh every item or visit a weighbridge every journey, and may not always appreciate how the kg's add up very quickly. Adding a full tank of water could mean inadvertently exceeding the maximum weight without knowing it. So I would just advise caution and calculation before driving with a full tank.

 

Regards,

[Don636]

Regarding the view that travelling with a full tank of water is inadvisable due to the risk of water sloshing and causing instability. Surely this is nonsense otherwise every vehicle on the road would be subject to such instability from fuel sloshing around in the tank or are they baffled in some way to prevent sloshing? Also I very much doubt that 100l or less of water moving around low down is going to destabilise a tall 3.5T van. What about all these window cleaning vans going around with huge tanks of water sloshing around in the back?

[Derek Uzzell]

When I began motorcaravanning in 1998 it was standard practice for UK motorcaravan manufacturers to quote a motorhome’s Mass In Runniing Order (MIRO) with no fresh-water allowance included. Subsequently a European standard was introduced that demanded that the MIRO figure included (amongst other things) an allowance for fresh-water of 90% of the motorhome’s fresh-water tank capacity. The present situation is that a motorhome manufacturer may specify the MIRO with a zero fresh-water allowance and this 2015 forum discussion refers

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Is-it-just-me-/39893/

 

There can be no argument that if a motorhome has, say, a freshwater tank with a capacity of 120 litres (as my 2015 Rapido 640F has) and that the tank sits on the motorhome’s interior floor (as my Rapido’s tank does) driving the vehicle with the tank full will impact negatively on the motorhome’s acceleration, braking and handling. On the other hand, unless one’s motorhome usage is such that the vehicle will be treated rather like caravan, a policy of only driving with minimal water in the tank will be an irritant.

 

Rapido’s technical documentation describes the 640F model’s fresh-water capacity (in litres) as 120/20 and highlights that their MIRO figure complies with European Directive EC 92/21 and that the allowance for fresh-water within that figure is (according to the motorhome model) 20 litres. But there’s no insistence within the Rapido technical documentation, nor within the Rapido User Manual, that the motorhome owner MUST restrict the fresh-water tank’s contents to 20 litres before driving his/her motorhome, nor (with the 640F model) is there any draining facility to ensure that tank’s contents can be accurately reduced to 20 litres.

 

Like Brian, when I've put water in my motorhome’s fresh-water tank I’ve always filled the tank until it overflows and, whenever I’ve seen other motorcaravanners fill their tanks, that seems to be what they do. It’s possible that some motorcaravanners arrive at a campsite/aire with just a few litres in the fresh-water tank, fill the tank, stay on the campsite/aire for several days and then drain the tank down to minimum before they leave, but I would have thought that procedure would be unusual.

 

Plainly, in Steve’s case, he’s aware that his Dethleffs motorhome’s rear-axle load-limit is such that he’ll need to take care regarding overloading and probably travel with not much water in the fresh-water tank.

[Deneb]

If I'm travelling to a site where I know I can get fresh water, I travel with a minimal amount in my tank, but if I'm wilding, I'll normally set off with a full tank so that I have a guaranteed water supply for a few days in case of any difficulties in finding a tap around my destination, and I tend then to top up to full again whenever I get the opportunity.

 

I also doubt that an underslung tank will have any appreciable effect on stability whatever its water level, but I've always understood that liquid tanker lorries and fire engines have baffled tanks to restrict their contents from excessive movement. On those vehicles, full or empty tanks are the safest driving conditions, it is the partially full tanks that can cause instability due to the movement of the contents.

 

Think of a roundabout, where the tank contents will roll to one side on entry, back to the other side as the vehicle negotiates the roundabout, and then again to the other side on exit, all possibly in quick succession allowing the momentum to build.

[Brock]

Every day articulated tankers come out of the Port of Liverpool carrying up to 35,000 litres of liquid. They bat along the M53 and main roads without looking unstable. My earlier three motorhomes had the water tank under the dinette seat and I could tell by the van's handling how much was in the tank. My last three vans have had tanks by the rear axle for stability with the latter two having some baffles.

 

My guess is that a properly designed and installed water tank - fresh or waste - is safe enough. My current van allows me to limit the content of the fresh water tank to 20l but there is no such device on the waste water tank which is behind the axle [i think]. Perhaps it is simply the need to comply with EU standards for calculating weights which focus manufacturers' attention on fresh water and not include waste water. My cassette toilet holds between 17 and 20l but I haven't seen anything to say it must be empty when driving.

 

 

[Brian Kirby]

Brock - 2018-11-06 11:38 AM...……………. My cassette toilet holds between 17 and 20l but I haven't seen anything to say it must be empty when driving.

If it's a Thetford toilet, have a peep in the Thetford manual! :-)

 

Re fuel/other tankers, my understanding is that all tanker drivers all have to take additional training, designed to ensure they understand, and drive to avert, the surge forces that can come into play when braking/cornering these vehicles.

[Brian Kirby]

Deneb - 2018-11-06 8:59 AM

 

If I'm travelling to a site where I know I can get fresh water, I travel with a minimal amount in my tank, but if I'm wilding, I'll normally set off with a full tank so that I have a guaranteed water supply for a few days in case of any difficulties in finding a tap around my destination, and I tend then to top up to full again whenever I get the opportunity...……………....

Have you weighed your van, fully laden, in both conditions, to be sure that you are not overloading when intending to wild camp. Unless you have, depending on where the tank is located, and the maximum contents of your fresh water tank, it seems you may be at risk, at the least, of overloading the rear axle.

[Derek Uzzell]

Brian Kirby - 2018-11-06 12:51 PM

 

Brock - 2018-11-06 11:38 AM...……………. My cassette toilet holds between 17 and 20l but I haven't seen anything to say it must be empty when driving.

If it's a Thetford toilet, have a peep in the Thetford manual! :-) ...

 

 

Brock’s reference to “between 17 and 20l” strongly suggests that he is referring to a toilet’s cassette, not to a toilet with an integrated flush-tank, as the latter’s capacity varies from 8 litres to 16.5 litres according to the model of toilet.

 

Thetford’s advice for cassette toilets that have their own integrated water reservoir is as follows:

 

"Important Warning Notice!

Please do not travel with water in the flush tank of your toilet. Failure to adhere to this notice may result in water damage to your caravan or motor home.”

 

This warning has nothing to do with the weight of the water in the flush-tank, and there’s no mention in Thetford’s documentation of potential risks if a leisure-vehicle is driven with the cassette full, nor any advice that the cassette must be emptied before the vehicle is driven.

 

To the best of my knowledge motorhome MIRO formulae have never included ‘weight’ figures for waste-water or toilet cassette/tank contents. Logically the weight of the water in a fresh-water tank wiill reduce in step with the weight-increase of the water that transfers to the waste-water tank, and a motorhome owner will normally empty the waste-water and toilet reservoirs completely rather than partially. There is, of course, the possibility that a motorhome’s fresh-water tank, waste-water tank, toilet cassette and fuel tank will all be full when the vehicle is to be driven, but the chance of that actually happening must be pretty small.

[Deneb]

Brian Kirby - 2018-11-06 12:54 PM

Have you weighed your van, fully laden, in both conditions, to be sure that you are not overloading when intending to wild camp. Unless you have, depending on where the tank is located, and the maximum contents of your fresh water tank, it seems you may be at risk, at the least, of overloading the rear axle.

 

Yes Brian, it's tight but do-able. We travel fairly light anyway, as regards things that we take with us. We are both happy to make compromises to achieve the type of touring we prefer, and don't feel the need to load our van to the gunnels with every little home from home luxury! There were for instance options that we deliberately left off of our van when we ordered it, because we didn't feel that the amount of use we would get from them justified the weight penalty, and we could put the saving to better use ;-)

[Brock]

My first three motorhomes had flush tanks but I never remember seeing anything about emptying them before driving. I'd have ignored the advice if it did because a family of four on long distance trips would have needed to flush the toilet.

 

The logic of fresh water:waste water doesn't always work for us. When we stay on site, often we will arrive with around 35l of fresh water. During our stay we will top up but we only dump the waste when we leave for good unless we remember to do it sooner. After going out for the day, we have a habit of driving past the waste point and having "Duh" moments. Allowing for the tea/coffee we drink, we could have 30l of fresh water and 60l of waste water by day 4 on site. Unfortunately logic is not always maintained when people are involved. At work we used to calculate what we called People's B--------- Factor to asses how much people would veer from the logic and mess up. I think my PBF as a motorhomer is a lot higher than most.

 

Lack of logic should be built into the motorhome design although I agree with Derek that the chances of a motorhome having full tanks is pretty small.

[Brian Kirby]

Brock - 2018-11-06 11:38 AM.....................My cassette toilet holds between 17 and 20l but I haven't seen anything to say it must be empty when driving.

Apologies John, you did say "empty" and what I had half remembered from the manual, was this (which I have since checked):

 

"S/CS AND CWE

 

The waste tank must be emptied, at the latest, when the

warning lamp is lit. It is advisable to empty the waste tank

earlier. The warning lamp illuminates when the waste tank

contains in excess of 15 litres. This indicates that a capacity

of 2 litres is left, which will allow approximately 5 uses.

Note! Do not allow the waste tank to become too full.

 

I assume this refers to driving as well as when static, but it is definitely not an instruction to ensure it is empty when driving. I think I had half-remembering the bit about emptying the flush tank (which ours does not have) and had Siamesed that with the above re the cassette. Don't know why, as I've never made a point of emptying the cassette before driving!

[Brian Kirby]

Deneb - 2018-11-06 2:00 PM

 

Brian Kirby - 2018-11-06 12:54 PM

Have you weighed your van, fully laden, in both conditions, to be sure that you are not overloading when intending to wild camp. Unless you have, depending on where the tank is located, and the maximum contents of your fresh water tank, it seems you may be at risk, at the least, of overloading the rear axle.

 

Yes Brian, it's tight but do-able. We travel fairly light anyway, as regards things that we take with us. We are both happy to make compromises to achieve the type of touring we prefer, and don't feel the need to load our van to the gunnels with every little home from home luxury! There were for instance options that we deliberately left off of our van when we ordered it, because we didn't feel that the amount of use we would get from them justified the weight penalty, and we could put the saving to better use ;-)

Wasn't trying to teach Granny to suck eggs :-), but it seemed worth raising the issue in case you hadn't checked.

[Don636]

Although I don't think travelling with a full tank of fresh or grey waste water is a problem other than the effect the extra weight has on fuel consumption, which I am also not bothered about, I can see that having lots of waste water sloshing around in the toilet tank might cause a problem with damage to the the

delicate plastic bits inside so I try not to travel with that container too full but wouldn't loose sleep over it.

[Brian Kirby]

Derek Uzzell - 2018-11-06 8:23 AM.......................Rapido’s technical documentation describes the 640F model’s fresh-water capacity (in litres) as 120/20 and highlights that their MIRO figure complies with European Directive EC 92/21 and that the allowance for fresh-water within that figure is (according to the motorhome model) 20 litres. But there’s no insistence within the Rapido technical documentation, nor within the Rapido User Manual, that the motorhome owner MUST restrict the fresh-water tank’s contents to 20 litres before driving his/her motorhome, nor (with the 640F model) is there any draining facility to ensure that tank’s contents can be accurately reduced to 20 litres. ……………..

I've had a look at 92/21 EEC, and it casts no light. It is primarily concerned with Type Approval. In effect, it merely says that the Mass in Running Order of a vehicle is whatever its manufacturer says it is, but that samples of that vehicle, once type approved, must achieve that weight +/- 5%. As stated in the article instanced in the MMM string linked above, quoting the NCC, it is OK if the manufacturer quotes MIRO with no water in the tank.

 

There is no requirement in that directive for the vehicle to be driven (or not to be driven) with no water on board, just that once the MIRO is stated by the manufacturer the difference between that and the MAM is the available payload, meaning that the owner can carry as much water as s/he wishes, but must ensure that whatever quantity that is, the vehicle does not exceed its MAM. So I agree, that 2016 change to the requirements to omit the obligation to calculate MIRO with the fresh water tank 90% full is regressive.

 

Personally, whenever we've bought a van, the first thing I do is take it to the weighbridge unladen (ie, full fuel, no water, no gas, no other load, and just the jack and wheelbrace) and weigh it. I then know what the gross payload is, and work from there. I maintain a spreadsheet that contains the actual weights of what we carry item by item (built up over time), and allows these to be distributed around the van in relationship to the rear axle. Once this is done, it calculates the loads on both axles, as well as the actual laden weight. I then re-visit the weighbridge in fully laden state to verify the calculations, and adjust if required. Thereafter, I check the axle loads on the spreadsheet from time to time as items are periodically added or removed from the van. I do this with full gas cylinders, full fuel tank, full water tank, and full toilet cassette, so that any change to actual load in use will be downward.

[Don636]

Wow Brian, that is some serious attention to detail. I have weighed my van in full trim twice - once it was 85kg over and the last time it was a few kg under, both times including full fuel and water tanks and both passengers. I believe you are allowed 5% over, which is 175kg so I think I should always be within that but that's not guaranteed as I don't pay that much attention to what I carry or check the weight every time. My view is that I am unlikely to be stopped and checked, quite likely to be OK but if not the van is on a Maxi chassis so can technically carry up to 4250kg without mods, paperwork permitting, so the van is never going to be unsafe. If I am found to be more than 5% overweight the penalty is only £100 and I wouldn't lose any sleep over that.

[david lloyd]

Don636 - 2018-11-06 7:09 PM

. If I am found to be more than 5% overweight the penalty is only £100 and I wouldn't lose any sleep over that.

 

Sadly though, Don636, if that were to happen following an accident you may find yourself uninsured. So it is worth some time and effort to try to remain within the weight limits even if the penalty seems low.

 

David

[Robbo]

Derek Uzzell - 2018-11-04 2:25 PM

 

I’m aware of SVTech’s advice, but Steve’s wish was to uprate his Dethleff’s MTPLM above 3500kg at nil/minimum cost.

 

His motorhome has 16”-diameter (steel) wheels as standard, so its 225/75R 16 tyres would already be adequate for a rear-axle load-limit upgrade. I believe the JR Consultancy exercise has just uprated the Dethleff’s MTPLM from its original 3500kg to 3850kg without changing the original axle-weight limits of 1950kg (front axle) and 2000kg (rear axle). As long as Steve can operate his motorhome without exceeding those maxima, there should be no NEED to uprate the axle-load limits, but as adding a 'semi-air’ kit to a Ducato X290 non-AL-KO chassis motohome like Steve’s Dethleffs is fairly straightforward and reasonably inexpensive (say £400 for the kit) and might well be beneficial in Steve’s case, it’s something to keep in mind. (Adding semi-air to an AL-KO chassis Ducato is more difficult and a good deal dearer.)

 

I've only just read this interesting thread with all it's various twists and turns.

 

Derek's post above, succinctly addresses the problem and solution in one foul sweep - open and shut case in my view.

 

Increase the permissible rear axle load to 2240kg using semi-air bellows on a non AL-CO chassis with 16" wheels and minimal deduction in useable payload for the added equipment.

 

What's not to like, apart from the £400 for the kit and the cost of the paperwork. A small price to pay for a useable motorhome without the worries of being overweight, within reason !!!

 

Hope we receive feedback from Ssnake (Steve) on his thoughts so far.

 

[Don636]

David - I hadn't thought about the insurance angle - point taken and thanks for that.

[Sssnake]

 

 

Hope we receive feedback from Ssnake (Steve) on his thoughts so far.

 

 

Cheers Robbo, see my post below. I’m happy with where I am now at 3850kg MTPLM, axle 1 1850kg, axle 2 2000 kg.

 

 

Than you to all who contributed to this, by way of an update...

 

I used JR Consultancy and have upgraded the MPTLM to 3850kg with no modifications. Cost was £180 and I received all paperwork and a new ‘sticker’ (placed adj to Dethleffs’ one) within a week. My V5 is at DVLA so I’ll probably get that back in April.

 

I went off on holiday last week with a full tank of water and fuel and the total on the weighbridge was 3620kg but I was 60kg over on the rear axle. I dumped three quarters of the fresh water tank and then came easily within all maximum limits. I didn’t have any bikes on the rack though so will need to reconsider what other things we carry in the summer but I’m confident I can balance this.

 

Take care a

[Derek Uzzell]

Sssnake - 2018-11-07 12:16 AM

 

Cheers Robbo, see my post below. I’m happy with where I am now at 3850kg MTPLM, axle 1 1850kg, axle 2 2000 kg...

 

Steve

 

In your posting of 27 September 2018 12:48 AM you said

 

"The Dethleffs ‘plate’ records 3499kg, 1950kg and 2000kg”

 

As 1950kg + 2000kg = 3950kg, it should have been practicable for your Dethleffs's MTPLM to be uprated to 3850kg as a simple paper exercise leaving the maximum axle-weights unchanged, and that’s what I had assumed JR Consultancy would do. But it now appears that, besides the original MTPLM of 3500kg increasing to 3850kg, 100kg has been shaved off the Dethleffs front-axle1950kg figure and 200kg added to the rear-axle 2000kg figure. This would be no bad thing (as it’s apparent that it’s the rear-axle that has the potential to be overloaded, and the 16” tyres can handle a 2200kg axle-load) - it’s just not what I expected. (I assume the JR Consultancy sticker clearly shows the revised axle-loadings as well as the MPTLM 3850kg figure.)

 

I’m sure you will have told your insurance provider about the weight data changes, but I suggest you keep quiet about them if the Ducato side of your motorhome should need under-warranty attention. Fiat won’t authorise this type of modification and, if it’s noticed and an under-warranty claim is made where it could be argued (by Fiat) that the cause of the problem is that the vehicle is being operated beyond its design weight limits, there is the potential for the claim to be rejected.

 

 

[Derek Uzzell]

Don636 - 2018-11-06 7:09 PM

 

...I believe you are allowed 5% over, which is 175kg so I think I should always be within that but that's not guaranteed as I don't pay that much attention to what I carry or check the weight every time...

 

This earlier thread discussed the +5% ‘allowance’

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Motorhome-weights-VOSA-Technical-Officer-s-view/46706/

 

(It’s perhaps worth pointing out that what happens in the UK may not apply abroad.)

[Brian Kirby]

Don636 - 2018-11-06 7:09 PM...……………... My view is that I am unlikely to be stopped and checked, quite likely to be OK but if not the van is on a Maxi chassis so can technically carry up to 4250kg without mods, paperwork permitting, so the van is never going to be unsafe. …………..

At least that should more or less eliminate the risk of rear axle overload (2,400kg max). The front axle will perhaps be a little more vulnerable as, although it's maximum load (2,100kg) is better then the "standard" chassis, due to their relatively long wheelbases many PVCs tend to run heavy at the front.

[Robbo]

Sssnake - 2018-11-07 12:16 AM

 

I’m happy with where I am now at 3850kg MTPLM, axle 1) 1850kg, axle 2) 2000 kg.

 

I used JR Consultancy and have upgraded the MPTLM to 3850kg with no modifications. Cost was £180 and I received all paperwork and a new ‘sticker’ (placed adj to Dethleffs’ one) within a week. My V5 is at DVLA so I’ll probably get that back in April.

 

I went off on holiday last week with a full tank of water and fuel and the total on the weighbridge was 3620kg but I was 60kg over on the rear axle. I dumped three quarters of the fresh water tank and then came easily within all maximum limits. I didn’t have any bikes on the rack though so will need to reconsider what other things we carry in the summer but I’m confident I can balance this.

 

Steve, I admire your optimism and wish you every success in balancing your weights between axles.

 

Bear in mind, the addition of 2 bikes to the bike rack @ 13kg each will add at least 45kg to your rear axle (based on a 2.5m rear overhang and allowance of 0.3m for the rack extension).

 

I'm a bit confused with regard to Derek's recent post referring to a permissible rear axle load of 2200kg. You state that your permissible rear axle load is 2000kg as per your original Dethleff plate.

 

I'm not particularly a fan of paper upgrades. Your recent visit to the weighbridge demonstrates that you now have a van capable of a total workable mass of 3560kg, unless you can transfer 290kg to the front axle. Not easy to achieve with a front lounge layout.

 

I respect your decision, it's your choice :-D