Rear axle weight on a vdj 79 landcruiser

Most GVM upgrades on this vehicle are to a maximum of 3,780kg. I say most, but there are some, like Lovell's that have an approval to 3,900kg.

The 3,780kg is not a coincidental number, it is the maximum combined axle limitation of the vehicle. Front 1,480kg and rear 2,300kg.

Under a GVM upgrade to 3,900kg the Lovell's kit will enable an increase in the front axle weight to 1,540kg and rear to 2,360kg. My experience with an upgrade to 3,900kg was that you are hard-pressed to get vehicle to maximum GVM without exceeding the rear axle limitation of 2,360kg.

Putting that aside your issue is that your rear axle weight is well above the OEM's limitation and also well above the rear axle weight that might be achieved by one of the GVM upgrade kits that are commercially available.

This leaves you with the prospect of needing to go through an approval process to get the axle weights increased, and this won't be an easy challenge.

I suggest you contact an engineering signatory and work with them on what is realistically achievable and what will be involved in getting the approvals.
I have written a blog on my experience with GVM upgrades and vehicle weight and you the link follows.

GVM Upgrade VDJ79

Good luck with sorting it out.

Baz - The Landy

It's a dilemma indeed....what to do with the GVM and load of the 79 series.
I had Multidrive Technology in Geelong extend mine by 500mm in the chassis and also fitted their rear diff extension (I was the test unit for the project). This gave me a certified upgrade to 3720 kg. Since then I've reworked the suspension and had an EFS upgrade with a 12 leaf rear spring pack, rolling sleeve airbags and a set of Toughdog big bore adjustable shocks (If I had the room, I'd have fitted a double shock system if I had the room believe me).

Using a mate of mine at VicRoads porta weighs, I cam up with the following figure without (unladen) and with (laden) my aluminium camper fitted.

UNLADEN LADEN DRY WEIGHT
Unladen Laden
RHF 825 RHF 800
LHF 850 LHF 800 2855 3380
RHR 750 RHR 1050
LHR 700 LHR 1000 CAMPER 475kg
3125 3650

If you are in Victoria, I'd suggest a an enquiry with 4x4 Obsession in Melton. Brett builds many of the comp rigs you'll see about the place and can provide good solutions and engineering for GVM upgrades. You've hit the nail on the head though in your reply to Baz. ....."If only I'd known at the start!"

Baz had a bit of an advantage in that he asked around before building. Always a good thing.

The best of luck with it.

Mick

Your axle is over its maximum capacity but don't forget that is only static weight. You would only have to drive over a car park speed hump and as the back wheels drop off the hump, the load coming down onto the axle housing will be well in excess of what you have now. It will be about ten times worse the moment you get out onto dirt roads.

This is why so many axle housings as well as chassis, wheels and wheel studs break in the bush.. Here is a few axle photosbroken housings

GVM upgrades should come with an upgraded axle housing, chassis. clutch, engine cooling system and just about everything else except the gear lever knob. The car manufacturer would do that if they wanted the car to carry or tow more.

The chassis could be your next problem but that will depend on how much heavy material you have back behind the axle. The distance between the axle and the tow ball or rear end of the tray is a lever. The further back you put heavy items the more the stress on the end of the chassis and the more weight you will put on the axle. bent chassis

That magazine story shows one dual cab Cruiser with a slight bend. Another photo in the magazine shows a much more noticeable bend in another one but the photo is not on the net.

How much weight is your camper putting on the tow ball? Camper trailers are notorious for damaging cab/chassis utes for two main reasons. 1. They often have far too much ball weight for something so short in length. They don't have long heavy ends to swing around like big caravans so they don't need huge ball weights to assist with stability. 2. They also usually operate in the roughest conditions so the end of the car chassis is constantly flexing up and down behind the axle.

No aftermarket springs or air bags can stop the far end of the car from being thumped down behind the axle and jerking the front up or having to instantly lift all of that heavy material whenever the front of the car drops down. The rear axle acts like the pivot point on a see saw.

The front axle does the same but you rarely if ever see any problems up that end because the distance between something like a heavy bull bar and winch back to the axle is very short so you don't get the severe leverage effect that you get at the rear end.

The maximum carrying and towing capacities of cars are for good sealed roads only. Loads should be reduced as the conditions deteriorate. The editorial in that magazine said you should have a 30 to 40% reduction in off road conditions.

A car designed to carry or tow the maximum for sustained periods in any conditions would most likely cost at least twice as much.

Another point with towing is have a look in the towing section of your owner's handbook and see if Toyota says anything about the use of a weight distributing hitch. They say one is essential for some of their models above a certain ball weight and yours may be the same. These hitches lever the far end of the chassis up taking weight off the axle housing and transferring some of it back onto the front wheels to assist with steering while the remainder goes onto the wheels of the trailer. Heavier springs or air bags can't do that.

The big problem with these hitches though is if the angle between the car and the trailer exceeds a certain limit, they can not be used because they can damage both the car and the trailer. Exceeding that angle is very easy to do in the bush.

I don't know what you are going to do now. The safest and most reliable way to travel around the bush is to buy a car that will tow and carry whatever you want without any modifications and with plenty left in reserve.

If everybody did that there would be a lot more happy holidays and the bush repair workshops would be out of business.

Clayton

Twenty years ago I tried all different ways to solve this & ended up going a 6 wheeler conversion 4500gvm & it was the best decision & after 650,000klms I sold it & bought a new one & again did about the same klms

you will hear a lot of bad reports of 6 wheelers & there are some real bad conversions done by so called experts but if there done right there great mine was great with a load & was not a problem traveling & it went everywhere & hard tracks & I seemed to tow more out that me being towed or winched, but empty it was a trap due to the weight spread over 6 wheels

good luck but beef up the chassie

G wagon GVM = 4,490kg.
http://www.mercedes-benz.com.au/content/media_library/australia/mpc_australia/passenger_cars_ng/specifications/australia/g-professional_specs.object-Single-MEDIA.tmp/2016.12-G-Professional_AU_WWW.pdf
Cheers,
Peter
OKA196 motorhome

Hullo Clayton
Friend of mine has a Travelander on a late model 79 series with a Lovells GVM upgrade.
When heading off he never loads up full water and fuel until he is out in the sticks as he is over the max GVM.
When I looked at various brands of slide on campers a while ago I recall that Overlander were the heaviest and that there was hardly a ute around that could legally carry them (putting aside the big ones from the US - eg, Ford, Dodge and Chev, etc)
Unfortunately, your cheapest (and best) option may be to cut your losses by the selling the Overlander and buying one that does meet the GVM requirements, for example, Tailgate Campers from Benalla , Vic. They make an excellent well thought out model and would be my choice ( btw, no affiliation)
Just as a matter of interest, did the people selling you the Overlander know what vehicle you were using? If they did, they were not selling you a product that was "fit for purpose"
Cheers
Andrew

Something that no one has mentioned yet. The 78 Dual cab is a very poor load carrier as far as the tray is concerned. Virtually the whole tray is behind the axle, For a better distributed load Toyota should have extended the chassis by at least 300mm. As usual for most car companies they took the quick and cheap method of using the same chassis length as the single cab 79. A 300mm chassis extension and 3900kg GVM upgrade along with some judicious weight loss measures would see you with a good setup. Good luck. Timnivo.

Gidday

Quite by accident today I came across a YouTube video from last week by the South African 4WD traveller Andrew St Pierre White in which he announced he was ditching a plan to build a new camping vehicle based on a dual-cab Land Cruiser.

Big call because he had only bought it a week or two before.

His reason? He did his numbers again and whatever he was building for the back was going to be too heavy and he could not get a suspension upgrade to cope.

Not much consolation for you Clayton I know. Hope you can get it sorted.

Cheers

Just a few questions:
Do you use the rear seats for kids or passengers? If not. what do you put there, and is it possible to move the water storage and maybe fridge forward to that area?
Where are your spare tyres and can they be brought forward (?roofrack)

Clayton C1

Another possibility is to put a lot of your gear in a little trailer. I am currently building a small one for that purpose.

My wife and I have done a lot of desert travelling including remote Beadell roads and the like but we always travel very light. We have a home made camper on a single cab. Fully loaded the stock standard car is always around 200 kg under GVM.

We want to take a lot more with us but not for desert trips. This will be for long stays in mountain camping areas along the Great Dividing Range. The trailer measures 1600 x 1200 and is divided into many separate different size compartments. Some of the items in it are not all that heavy but they would take up too much room in the car.

The spare wheel is suspended by a ute spare wheel winch up under the floor in front of the axle.

The chassis is steel but the box section is plywood. We have used all plywood and meranti campers all over the country for decades and have yet to break one.

The axle is hollow and 60 point something mm outside diameter.

Some things in it will be taken out of the car further reducing its weight.

The finished trailer will be around 280 kg and will carry about 200kg

The car will now be even further under its GVM and the trailer will be miles under the maximum towing capacity.

That may be the best way out of your situation.

Clayton,

Drop me an email, address in profile.

Cheers, Baz

An acquaintance recently got his brand new GU Patrol fitted with a GVM upgrade, part of that was to weld bracing to the rear diff (parallel to the axles) to support the extra load.

Do they offer something similar to this for the Toyota?

just saw the results last week of a new new V8 cruiser ute that had a a gvm upgrade and was over max gvm when this incident happened.

LH rear u-bolts broke taking out the airbag and cracking the RH axle housing between the spring and the axle.

The 79 Dual Cab cruiser used in the 4wd show "All For Adventure" clearly is a heavy duty vehicle carrying a lot of weight and also towing a lot of weight so it might be worthwhile contacting them to see what the actual specs of their vehicle is and what was done to achieve their load carrying capacity.

http://danaperformance.com.au/dana-performance-for-landcruiser/

Dana sell a heavy duty axle which also matches up the track width to the front wheels

Not sure on the price but sounds like it fits the requirements for off road heavy loads etc.

Cheers

Personally I would always be worried about loading these Toyota twin cabs because the axel is way to far forward if it a poorly designed vehicle just aimed at cashing in on the ever expanding twin cab market. If the rear axel was positioned correctly near the centre of the tray you probably wouldn't need any spring up grade and it would be a safer vehicle to drive if you loaded it sensibly. I work with a fellow who put 350kg springs under his and with his canopy fitted their not heavy enough to support the weight safely that's mind blowing because that's 350kg over what the original springs are rated at whatever that is so when does common sense kick in and say maybe this it really getting to dangerous to drive now he's looking to see how much more he can spend in modifications to his expensive toyota ute with it's massive rear tray over hang just following in the footsteps of others who have purchased the wrong vehicle to suit their needs.

This group of issues comes up time and time again.

The whole slide on camper proposition is fatally flawed, even on a single cab 4wd, as soon as you say the words "dual cab" ....... it's pretty much an impossibility.

so here we have a GVM upgraded vehicle that will be even then near or over weight AND it will be used on other than smooth improved surfaces.

And a horrificaly high centre of gravity

The whole concept is is a disaster.

sorry

cheers