HomeRVwhat it's, what's concerned & how one can get...

what it’s, what’s concerned & how one can get one


In case you weigh your caravan and it’s chubby, what are your choices? Right here’s how one can get a caravan ATM improve and what’s concerned.

Probably the most talked-about topic amongst caravan homeowners is weight compliance, and to many, the entire topic might be downright complicated. With many new {couples}, singles and households entering into caravanning, there has by no means been a extra essential time to ensure you absolutely perceive all the load terminologies and guarantee your rig is compliant.

Let’s take a fast have a look at the terminology

Earlier than we speak about caravan ATM upgrades, let’s take a look in any respect these weight terminologies and acronyms which might be recorded on the caravan compliance plate. These rankings and capacities are there to make sure your caravan is authorized and in a position to be operated safely.

caravan ATM upgrade
Compliance plate on a caravan

Tare Weight (TARE)

Tare weight is the entire dry weight of the caravan because it leaves the manufacturing facility with all equipment fitted, together with empty water tanks and empty gasoline bottles. This doesn’t embody aftermarket gadgets fitted after manufacture by the caravan supplier or a earlier proprietor.

Towball Mass at Tare

The Towball Mass at Tare is measured on the tow hitch with the caravan degree. This weight is added to the wheel weights to calculate the empty caravan’s Tare Weight.

Towball Mass (TBM)

Towball mass measures the load the caravan tow hitch imposes on the tow automobile. Most producers lately don’t specify a most allowable Towball Mass on the caravan compliance plate. If so, the utmost obtain for the caravan tow hitch is then decided by the allowable tow ball obtain of the tow automobile.


Gross Trailer Mass (GTM)

The GTM is the utmost allowable weight that the absolutely loaded caravan imposes on the bottom by its wheels and axles.

Combination Trailer Mass (ATM)

The ATM is the entire weight of the absolutely loaded caravan, unhitched from the tow automobile. The ATM contains the entire weight imposed on every wheel plus the load imposed on the tow hitch. These measurements all have to be taken on the identical time to make sure the result’s right. So TBM + GTM = ATM

Axle Group Loading (AGL)

The AGL information the axle capability of the caravan, which is often decided by the chassis producer or the axle producer.

caravan ATM upgrade
Weighing the van on transportable scales

First issues first – get your caravan weighed

Now that you understand what all of the weights imply, the subsequent factor to do is get your caravan weighed. Do not forget that to be compliant, it’s essential guarantee you might be below all of the compliance rankings: Towball Mass, Gross Trailer Mass, and Combination Trailer Mass. We’ve spoken beforehand to Dave Lewis from Weightcheck, a cell caravan weighing service, and he experiences that over the previous three years, round 45% of the caravans he has weighed have exceeded their ATM. Many others had issues with their TBM or GTM.

As a way to obtain probably the most correct outcomes, Dave factors out an important piece of recommendation:

Weighing the caravan entails measuring the load of every wheel and the tow ball obtain all on the identical time, sure, all on the identical time. First, the caravan have to be on the identical altitude or angle as it’s when hooked up to the tow automobile. The tow ball mass should even be measured with the tow hitch on the identical peak it’s when hooked up to the tow automobile. Something apart from it will imply the measurements, particularly the TBM, is not going to be correct.”

It’s chubby!

Okay, you’ve weighed the caravan and now, to your dismay, you realise that you’ve got an excessive amount of gear. It has exceeded the ATM, GTM, or TBM or possibly all three. So what are your choices to get round this nightmare and guarantee your caravan is compliant?

Firstly, don’t panic. Have a critically good have a look at how one can cut back weight within the caravan. You need to be a tough taskmaster, and we advocate going by each cabinet and drawer and if it’s not completely important {that a} sure merchandise is in there, then take it out.

Open up that entrance boot and type out all these instruments and different stuff all of us take simply in case one thing breaks. Realistically, you in all probability don’t want a few of it. Subsequent, get the toilet scales and weigh all the pieces that comes out, irrespective of how small or insignificant. One in all Dave’s current prospects did precisely this and was in a position to pull 63 kilograms out of the caravan within the blink of a watch.

Getting extra payload

So, you’ve had a cull, and the caravan remains to be over its ATM, so what’s your subsequent possibility? How do you get extra out there payload in your caravan? The reply could also be an ATM improve, which entails rising the payload of the caravan by overriding the unique compliance plate rankings.

The method could be very advanced and thorough and may solely be accomplished by a licenced engineer, who additionally must be an accredited particular person with the related state transport authority. If all goes to plan, a Modification Plate shall be hooked up to the caravan beside the unique compliance plate, with the related paperwork submitted to the State Transport Authority to mirror the brand new ATM on the caravan registration.

caravan ATM upgrade
Anatomy of a chassis

How a caravan ATM improve works

So, let’s have a look at what’s concerned in a caravan ATM improve and the way it works. Most engineers will first provide an evaluation sheet that gives the formwork to determine whether or not an improve is feasible with the caravan in its present state with out the necessity for structural modifications. The main points from the present compliance, specifically the Axle Group Loading, play an vital a part of the evaluation. There are additionally many rankings and sizes of varied caravan parts that can have an effect on the end result. Let’s have a look at a few of them.

  • Tyres: The tyre measurement, load ranking, most strain ranking, and the tyre date code.
  • Rims: The rim measurement, load ranking and sort of building (alloy or metal).
  • Coupling: The make, load ranking, sort (ball or off-road), and the bolt measurement and sort of nuts.
  • Chains: The chain measurement, variety of chains, and markings (Aust. Requirements AS4177)
  • Suspension: Kind of suspension (Leaf/Coil/Torsion/Airbag)
  • Springs: Kind of spring, (Slipper/Rocker/Curler), width, thickness, and variety of leaves
  • Axles: Kind of axle (straight/drop/overlay), form (spherical or sq.), and the load ranking
  • Bearings: Kind, measurement, and cargo ranking
  • Brakes: Brake sort (disc/drum) and measurement (10in/12in)

Required measurements

There are additionally plenty of measurements that have to be taken, which type the premise of the evaluation. These measurements permit the engineer to determine if the caravan’s chassis is robust sufficient to deal with the elevated payload, in addition to guaranteeing it would deal with safely and predictably when being towed. These measurements are entered into a pc program that then calculates the impact the brand new payload has on the tolerances of the present, unmodified chassis.

The measurements embody:

  • Drawbar size
  • Tow hitch as well
  • Wheelbase
  • Chassis overhang
  • Axle unfold
  • Hanger unfold
  • Crossmember size
  • Outrigger size
  • Coupling plate thickness
  • Crossmember measurement
  • Chassis measurement (size x width x thickness)
  • Chassis reinforcement, if relevant
  • Drawbar measurement (size x width x thickness)
  • Drawbar reinforcement, if relevant

If any of the element rankings or measurements don’t meet the rules, the engineer will make suggestions as to what repairs or modifications would have to be carried out, with the intention to proceed with the improve. This may increasingly require work, for example, to bolster the chassis or drawbar or improve or improve the scale of a chassis element akin to brakes or axles to ensure that the evaluation to proceed.

caravan ATM upgrade
The suspension and axles have to be as much as the duty as effectively

The ultimate a part of the evaluation

The ultimate a part of the evaluation is a full inspection of the chassis and caravan that hopefully is not going to present up any defects that make the improve unachievable. It’s worthwhile noting that this might show a bonus as a result of if a fault is found throughout this inspection, it’s doubtless the proprietor was in all probability unaware of it. Dave Lewis just lately referred a buyer with an chubby caravan to an engineer for a possible ATM improve, solely to find that the caravan chassis had a number of hairline cracks and it wanted some pressing restore work. As soon as accomplished, nonetheless, the caravan was in a position to have an ATM improve.

The improve will usually improve the compliance ranking of each the Gross Trailer Mass (GTM) and the Combination Trailer Mass (ATM). The engineer can also counsel that the Towball Mass (TBM) be maintained at a sure weight to ensure that the caravan to be towed safely with the elevated payload.

As soon as the evaluation is full and the engineer is happy the caravan will deal with the elevated payload, they may full all of the related State Division of Transport paperwork and fix a Automobile Modification Plate that specifies the upgraded compliance rankings. These new rankings are then recorded on the caravan’s registration certificates.

And eventually…

Earlier than ordering a caravan ATM improve, the very first thing to do is get your caravan and tow automobile weighed when absolutely loaded. There are six compliance rankings that have to be checked, together with the Gross Mixture Mass, which is the entire weight of the caravan and tow automobile mixed. As an example, in case your rig is below its GCM, however the caravan is over its ATM, then the choice is there to look into an ATM improve. Bear in mind, it’s a completely different story if the caravan is over its ATM and the rig is over its GCM, so it’s essential get the larger image first.

The very best recommendation is to get good recommendation earlier than you determine on a path to comply with.

Phrases by Dave Lewis, Weightcheck, Brisbane.