Chassis ATM UPGRADE SUCCESS NSW 20.6 EXPANDA

Pottsie

New Member
Aug 13, 2016
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Culburra Beach
Hi All,
In August 2016 I purchased a 10 month old Jayco 20.6 Expanda. Its Tare weight was 2615kg and ATM 3090 giving a payload of 475kg. I then started customizing the van by adding the following…… 2nd battery, storage box on A-frame, washing machine, rear bike rack, grey water tank, and underbody protection. These mods effectively consumed over 100kg of the payload.

Aware that we would be pushing the max ATM when loaded up for a trip, my wife and I were careful not to load the van with unnecessary camping equipment etc. A visit to the weighbridge prior to going away confirmed our fears with the van weighing 3260kg, over weight by 170kg.
The water tanks were full so they were drained allowing us to travel, albeit at our max weight.

An ATM upgrade to 3400kg was needed and after getting nowhere with Jayco head office, the following describes how it was successfully achieved.
An engineer licensed with the Roads Authority as a vehicle certifier was required to undertake the process. I had Troy from Finke Engineering Unanderra come look at my van for an assessment. He took measurements and photos so that he could compile a report on what mods may be necessary. The report (attached) indicated that the chassis rails needed stiffening with the addition of welded fish plates (see photos), the draw bar to be fully welded not just stitched welded, and the coil springs upgraded. The stock wheels, tyres, axles etc were deemed to be of sufficient capacity to carry the new ATM of 3400kg.

Aware this was not going to be a cheap exercise I moved forward with the proposed changes.
The welding was carried out by a company recommended by Troy at Finke Engineering and I purchased the stiffer springs from Jayco . When all was completed Troy inspected the work and provided the necessary reports and compliance certificate for me to present to the Roads Authority. I first had to have the van weighed at a registered weighbridge so that a new Tare weight could be recorded on the registration papers. The new tare was 2760kg giving me a 640kg payload, keeping in mind that all the accessories I added at the start were now a portion of the tare weight and not the payload as before.

How much did this cost???? Engineering $1100
Welding $1700
Springs $344
TOTAL $3144

Hopefully somebody finds this info helpful.

Cheers
Pottsie
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  • Finke Report.pdf
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Macca_75

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Aug 3, 2016
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Great write up. I We had our payload upgraded at purchase (2016 20.64.1) without the extra bracing, I would need to check but am assuming still a stich welding and so on.

But having the second battery and everything in your payload is A+

Well done.
 

Pottsie

New Member
Aug 13, 2016
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Culburra Beach
Thanks Mecca. If I purchase a new van in the future I will be sure to do as you did and negotiate sufficient payload in the contract.
Cheers
Pottsie
 

Smergen

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Jun 8, 2014
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That's a really well done and thorough process and I appreciate you sharing it.

Out of interest, what do you tow the big girl with?
 

Drover

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Great report and I found it very interesting, especially the metal work pics ............... with my Ute loaded I wouldn't legally be able to it.
 

Smergen

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Great report and I found it very interesting, especially the metal work pics ............... with my Ute loaded I wouldn't legally be able to it.

Not many could mate. Hence my question as @Pottsie seems very clued on to the world of weights so I'm interested to know the tug boat.
 
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Pottsie

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Aug 13, 2016
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I have a Ford Ranger which means with a GCM of 6000kg I am still doing a balancing act. The only accessory on the car is an ARB alloy Bull bar for our outback travels. We are careful to only take away what we are sure to use and have a few empty cupboards in the van. Last time on the weighbridge I was just under the 6000kg GVM. I figured I could only become lighter from that point as we consumed the beer, wine ,food etc. The only heavy items in the Ute tray were a generator and an Oz Pig.
 

Smergen

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Cheers Pottsie... oh the joys of not having to cart a whole bunch of stuff in your car! With the mods to the Rock Truck just means towing something that big just blows the GCM out of the water for me. Well done on being responsible and all across it. Many aren't.
 

Pottsie

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Aug 13, 2016
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Culburra Beach
Thanks Smergen. Even though the combination tows beautifully I don't like being at the maximum limit. A 200 series with perhaps a GVM upgrade would be the answer, but you have to ask yourself where does it end.
 

Drover

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So long as you are using weigh bridge tickets and not compliance plate fantasy, around the campfire tonight a fella with a 79 series showed me his weigh bridge ticket, GCM was all good but he blew it on GTM for van and GVM for tug by a hundred odd kg on each, checked the compluance plates, I explained to him vehicle weight compliance requires a number of boxes ticked before you pass....GTM, ATM, GCM and GVM must all be ticked, over on any and you fail, if you dig deeper you can tick all of them and fail an axle load.... The bean counters in government don't make it easy....... I reckon 200kg under GCM is good then your not flogging the crap out of your vehicle ......
 

Crusty181

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Feb 7, 2010
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Thanks Smergen. Even though the combination tows beautifully I don't like being at the maximum limit. A 200 series with perhaps a GVM upgrade would be the answer, but you have to ask yourself where does it end.
It ends when order a new any new Landcruiser because you'll be broke. I have personal knowledge of this. Interesting post @Pottsie, I had the ATM of our 20ft'er decreased at the factory to match our then tow vehicle, and now I can tow 3.5t Jayco wont give it back. Im looking to add some ATM to our 20ft'er in the not too distant future, so Ill add my process in due course
 

BJM

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Sep 29, 2018
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I wonder how the engineer decided where /why to put the strengthening plates etc on Pottsies 20.6 Expanda. This apparently only gives around 200kg.extra ATM. which is spread over 4 load bearing wheels with independent suspension and two exterior frame sides of the van chassis.This still does not address torsional stress etc,which maybe worse (new springs) now on the rest of the chassis and suspension frame..I also note the van has the Enduro GT tyres. On my 16.5 2 wheel Journey Outback Poptop these tyres are at their load carrying limit when the van is at max legal towing weight.!! My mate towed his Silverline with a new Ford Ranger trayback. Well overweight when loaded ,plus it was the tail wagging the dog on the road.White knuckle stuff.Sold R and bought 11 year old LC100 now found he is still overweight. A vehicle with a 3.5 towing capacity is the max the vehicle should tow, towing this max weight day in and out will put huge stresses on both tow vehicles and the van.Plus the driver!
 

Crusty181

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Feb 7, 2010
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I wonder how the engineer decided where /why to put the strengthening plates etc on Pottsies 20.6 Expanda. This apparently only gives around 200kg.extra ATM. which is spread over 4 load bearing wheels with independent suspension and two exterior frame sides of the van chassis.This still does not address torsional stress etc,which maybe worse (new springs) now on the rest of the chassis and suspension frame..I also note the van has the Enduro GT tyres. On my 16.5 2 wheel Journey Outback Poptop these tyres are at their load carrying limit when the van is at max legal towing weight.!! My mate towed his Silverline with a new Ford Ranger trayback. Well overweight when loaded ,plus it was the tail wagging the dog on the road.White knuckle stuff.Sold R and bought 11 year old LC100 now found he is still overweight. A vehicle with a 3.5 towing capacity is the max the vehicle should tow, towing this max weight day in and out will put huge stresses on both tow vehicles and the van.Plus the driver!
Hey @BJM are you an engineer, or just say'in. Im looking at going down a similar road, so Im interested in any feedback.
 

BJM

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Just Sayin !! I have rebuilt a few vans over the years.The Jaycos like my 2015 Journey Outback poptop have a floor that is glued and screwed.In some areas of mine on the cross members the glue has let go.I have also seen the ply floors crack.Probably from a twisting action.A redeeming feature of the 4 wheel independent it is much kinder on components than dual straight axle setups. It also has a substantial frame that the trailing arm suspension is attached to. . I just think a great lump of steel plate on the outside of each chassis rail may not really be needed.
 
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Drover

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Most 3.5t tow cap vehicles when loaded can only tow 2.8t anymore and you blow the GCM, I reckon if you need to spend heaps of $$$ upgrading for increase GCM then you have the wrong vehicle, upgrading just means your flogging it, since majority of folks have no idea about weights overloading will continue, the tyres on new vans are usually cheap rubbish fitted for cist and bling.........
 
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Drover

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Hey @Pottsie don't think we are rubbishing your upgrade mate, its really very good and something that shouldn't really be needed if things are built and tagged properly.

One thing I did notice in the pics, you need to upgrade your jack, that scissor Jack is a killer, if you use it on anything other than flat concrete it has a 99% chance of collapsing, cut it up throw it in the bin they shouldn't be used at anytime, get a bottle jack and a nice solid base plate, live longer.

@BJM I have often wondered why they don't hang suspension off its own frame with the van chassis mounted on it, easier to work on and handle flex.............when I replaced the suspension on my 14.44 I found on one of the hangars they had burnt thru the chassis when they welded the hangar on originally, a stressfull thing to find and patch up.
 
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BJM

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Drover.
The JTech independant suspension as on mine and Pottsies is built on a separate frame that is then welded to van cross frames and chassis rails.It is a substantial unit in its own right. Thats why I questioned the need for the side plates.It would need a huge amount of stress to bend the original fittings/components etc.Something else would go first.!!
 
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MDS69

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Drover.
The JTech independant suspension as on mine and Pottsies is built on a separate frame that is then welded to van cross frames and chassis rails.It is a substantial unit in its own right. Thats why I questioned the need for the side plates.It would need a huge amount of stress to bend the original fittings/components etc.Something else would go first.!!

Yes I believe vans with Jtec suspension have a smaller payload due to the extra weight of the suspension system on comparable older vans with a solid axle.
I was surprised by the side plates as I always thought the chassis on OB vans was overkill to begin with. My observation only, no technical knowledge to back that up.
 

Pottsie

New Member
Aug 13, 2016
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Culburra Beach
Don't worry Drover. I am all good with the discussion. As you said most folks don't have a clue about weights and may become more informed by us posting our experiences. The caravan manufacturers could be doing a lot more to build lighter stronger caravans, but that would probably come at a cost..
As BJM mentioned the JTech suspension is solidly constructed and so I also wondered what the side plates were going to achieve in that location. Not being an engineer I accepted the certifiers report and got on with the upgrade.
 

MDS69

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@Pottsie I love your opening post. Your the first person I can recall that has completed this process ( sorry if others have I just don’t remember) and it has been documented well in English in what looks to be a simple step by step process. I am sure you had a lot of road blocks and set backs initially but your outcome gives the rest of us who may want to go down that path some hope.