A lot of people are now familiar with GVM and GCM limitations, but that’s just the tip of the iceberg. Those are the two easiest weight limitations to pass.
However, just because you’ve passed them doesn’t mean you are legal; there’s several other items that need to be considered too and in this post we explain what they are, and how it relates to our own setup after having a mobile caravan weighing company go over our fully loaded setup with a fine tooth comb.
Please note we are towing a reasonably light weight hybrid camper trailer, and using an Isuzu Dmax that is not that excessively modified, and we are still pushing the friendship with weights, as you’ll see below.
If you are towing anything heavier, or using a very modified 4WD you could be close, or well over one or more weight limitation. This renders your towing setup illegal, and your insurance potentially void in the event of an accident.
The results of the mobile weighing service were quite interesting, and it proves how easy it is to have an illegal setup. In fact, we were told that around 60% of setups that are weighed are illegal in one way or another, and that’s pretty scary.
These are people who’ve volunteered to have their setups weighed; what about those who don’t have a clue, or just turn a blind eye?
If you are still struggling with understanding what weights you need to comply with, we wrote a very simple guide that makes it super clear for anyone, and you can get your vehicle figures and follow along. You can read this here – Towing capacity; a simple guide to ensuring you are legal.
When we built our Isuzu Dmax I took it over a weighbridge a couple of times, and ended up with a GVM upgrade as it was pushing the boundaries too much.
Of course, a lot of thought went into weight distribution and whether we’d be legal, and with a light weight tow ball weight I was fairly confident.
The risks of not being under weight are simply not worth the chance though, and with a big 6 week trip planned with as much gear as we’d ever take loaded in, I booked a session with a mobile caravan weighing service.
Changes to our setup
Soft floor to Hybrid
We mentioned the transition earlier, from a 1250kg soft floor camper trailer to a 2200kg Hybrid (at a guess; it can go all the way to 2600kg as needed). Our current setup is below:
The only real concern for us in doing this was the heavier tow ball weight. Ideally you have somewhere around 10% of the trailers weight on the tow ball, and a heavier trailer means a heavier ball weight.
Tow ball weight make a massive difference as well, with the leverage from the distance between your rear axle and tow ball weight.
For example, on many dual cab Utes, a 150kg tow ball weight applies about 216kg of weight to your rear axle. It does this by shifting 66kg of weight off the front axle, to the rear.
If you want to know more about why tow ball weight is so critical, have a read of this; Tow Ball Weight; what is it, and why is it so important?
Upright Fridge, ply and packing changes
Not long before our trip up north we sold our Evakool Fridge and purchased an 85L upright fridge. There were plenty of reasons for doing this, but one of the major ones was a significant decrease in weight.
I would say we comfortably lost about 30kg in weight by doing this. It also takes up far less room in our canopy, and I cut some extra ply out that wasn’t needed to reduce weight even further.
We are also onto our 4th or 5th style of packing the canopy of the Dmax, with the emphasis on putting as much weight as far forward as possible.
The fridge, 50L water tank, 45kg battery, tools, nuts and bolts and anything else that is heavy is on top, or in front of the rear axle to reduce the leverage and risk of chassis damage.
For anyone looking at the above photo and thinking it looks heavily packed, know that nothing backwards of the Stanley tool box is very heavy. We have light weight plywood on the other side, plastic drawers all carrying light weight gear and everything else is empty or weighs nothing.
The red tub has wetsuits/snorkels in it, the bin is empty, the 20L white container is empty and its all just bulky, light weight gear. Anything heavy goes into the Hybrid Camper which has a much greater payload.
Everything heavy is either in front, or over the rear axle.
Long Range Fuel Tank
I always wanted a long range tank, but put it off for fear of being overweight. However, once we started towing the Reconn R2 around our fuel range was dropping to around 400km, which is totally impractical.
You end up filling up at expensive fuel stations in remote places, which increases your chance of dodgy fuel, makes you stop more often and having to deal with jerry cans is just a pain in general.
A few days before departure, ARB in Canning Vale fitted a 140L plastic Frontier fuel tank, which is equivalent to taking 3 jerry cans (which we were doing anyway – 2 in the front of the R2, and one in the rear of the canopy).
I’m told the plastic tank weighs about the same as the factory 76L fuel tank, and being in front of the rear axle I figured it wouldn’t make a huge difference.
We were either going to take 20kg of diesel in the canopy, and 40kg (roughly) right at the front of the Reconn R2 (which would have increased tow ball weight) so this seemed like the lesser evil.
When we built the Dmax, we only had one kid. We’ve now got two, and that means twice as much gear, two car seats (which are pretty heavy) and even less room. Lucky for us they are 12kg and 16kg, so not a huge weight burden just yet!
Rear axle weight woes
The only real concern for us was the rear axle capacity on the Dmax. I was pretty sure we’d be fine for everything else, but a dual cab Ute inherently ends up with a high rear axle weight because of how much storage space is behind the rear axle.
On top of this, the ARB GVM upgrade that we had done lifted the GVM by a few hundred kilograms, but it did not change the rear axle capacity. This means its still at 1870kg, which might seem like a lot but it adds up quickly especially when you consider the leverage effect of tow ball weight.
Getting it weighed
The weight of your setup can change dramatically, and we decided to get it done when it would be at its heaviest; right before a 6 week trip up north with all the gear we choose to take to be comfortable.
This included 340L of water, 2 gas bottles, 88L of frozen food and bait, 76L of fridge space full to the brim, firewood, 140L of diesel, 2 children, 2 adults and every other piece of gear that we need.
Doing the weighing a couple of days prior to departure allowed for everything to be fully packed as we’d normally travel (or as we would travel full time).
This is super important; your weights can change hugely from day to day, so get it done at its heaviest, and then you know you’ll be fine as the weight shifts, or decreases.
How is the mobile weighing done?
There are mobile caravan weighing services in every state of Australia today, or you can go to a weighbridge and do it yourself, but it needs to be done very carefully.
It is so much easier to have someone come to you, and to spend the time needed to get accurate results.
Finding a weigh bridge that is accurate for 4WD’s, flat enough to measure axle weights and allows you enough time to take all of the needed weights is tricky, even if you pay a fee. To do it properly you need to disconnect the trailer and then re-connect it, and you’d be pushing to do it accurately in a hurry.
Beyond this, a lot of people don’t fully understand the weight requirements that you need to meet, and having a professional come and do it all for you is well and truly worth the fee.
In our case, the mobile weighing service came to our house, and we deemed the driveway and garage just suitable to do it without having to move to a larger, third party location.
Firstly, you hook the trailer to the vehicle, and you weigh each trailer wheel. Then, you disconnect the trailer and you weigh the tow ball weight, using tow ball scales.
Please note what is used is not the cheap spring loaded scales that can be hugely inaccurate (even between two identical, new units), but a proper digital loadcell that is regularly calibrated.
From there, you hook the trailer back on, and you weigh all 4 wheels on the vehicle. Overall, this gives you the vehicle weight, or GVM (which includes the tow ball weight), your trailer GTM and ATM, trailer tow ball weight, and the individual wheel loads.
These are then compared to the manufacturer specifications to see if you are under, or over in each weight category. If you are over, you might get an opportunity to juggle a few things around to correct it.
What were the results?
Maximum 3220kg (factory GVM is 2950kg, but we had a GVM upgrade). Weighed in at 3089kg including the tow ball weight. Under by 131kg, or 4.24%.
If you want to know more about the specifics of the Dmax in terms of weight, you can check this out – Isuzu Dmax touring setup weight.
Maximum 5950. Weighed in at 5166kg. Under by 784kg, or 15.17%
Front Axle Weight
Maximum 1350kg. Weighed in at 1317kg. Under by 33kg, or 2.44%
Rear axle weight
Maximum 1870kg. Weighed in at 1772kg. Under by 98kg, or 5.53%. As expected, the rear left is 158kg heavier than the rear right, because of the long range tank, fridge, kitchen and heavy battery in the Dmax. Not ideal, but not the end of the world either.
Maximum 2600kg. 1560kg empty and weighed in at 2209kg including the tow ball weight. Under by 391kg, or 17.7%. Also under the 3500kg towing capacity by 58%. The camper is almost equal from left to right, which is a great result.
For more information on the trailer, check this out – Reconn R2 Hypercamper. Below are a few photos of how it was loaded.
Tow ball weight
Maximum 350kg. Weighed in at 132kg. Under by 218kg, or 265%
Overall, everything passes, but its very tight in a couple of areas.
We are really stoked. I was sure we’d be close to the rear axle capacity, but to know we are under by almost 100kg is absolutely epic given how much gear is on board.
The tow ball weight is only about 5.98% of the trailer weight which is on the lower side, but given it tows fine, and I’m cautious of applying too much leverage onto the chassis for when we are off road, it’s perfect.
If you are getting above the 150kg tow ball weight for real off road use, and don’t have a wagon or seriously strong chassis you could be asking for trouble.
The only caveat for us is we need to monitor the front axle weight, as when you remove the trailer from the mix and are driving around town extra weight is applied to the front axle, and given how close this was we could well be over if we have the rear of the vehicle too light.
If you are close to any weight limits, you could be illegal
This exercise made it so clear that the maximum weights all marry together, and if you are close to one, you are likely to be close, or over on another. For example, you might be under GVM, but if the weights are not distributed perfectly you could easily be over on axle weights.
This is especially the case when you travel, and your weights change. What happens when your water tanks run dry and some weight is transferred elsewhere? It isn’t possible to be at the upper limits of all weight requirements without being over in at least one, as they change on a daily basis.
We are well under our GCM, ATM and Tow ball weight, but close to our GVM and rear axle weight, and very close to our front axle weight. If we had a higher tow ball weight (like most hybrids and caravans do), we’d be closer to our GVM and rear axle weight, and it wouldn’t take much to tip us over the scales.
It makes it so clear that your setup needs to have plenty of spare weight capacity in each area for what you are doing. If you are right on the edge of any weight limitation, you are likely to be illegal in one category (or more).
Hopefully this post has provided some insight into the different weights, and might provide you with some motivation to get your own setup weighed.
A huge thanks to Gary at Caravan Weighing WA, and $200 well spent. Yes, we paid full price for this service.