Rear Suspension Advice

Submitted: Saturday, Mar 22, 2014 at 10:17
ThreadID: 106838 Views:8498 Replies:10 FollowUps:5
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We have a 2005 Mitsubishi Triton Single Cab 4wd with standard leaf springs. On the back is an all enclosed aluminium canopy, side wheel ache boxes (one with a 40kg battery in it) and soon to be an 80L water tank. When fully loaded up to go camping it now sags a fair bit in the rear end, a little bit more on one side due to fridges and the battery box.
We’ve been to a couple of places now to get advice and to see what our options are but would like to get some views, advice from what people who have done anything with their suspension.

We are considering heavy duty leaf springs, Polyair Bellows (but are concerned about bolting to the chassis) and the Ironman Load Plus Helper Spring Kit.

Any assistance would be much appreciated.
Cheers, Daryl.

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Reply By: AlbyNSW - Saturday, Mar 22, 2014 at 10:32

Saturday, Mar 22, 2014 at 10:32
I think you need to put heavier springs in, bellows should only be used for fine tuning in this situation and helpers are a partial solution and may hang low and get caught up off-road

You could have a look on site for more specific info or speak to Ultimate suspension in Sydney as they have had a lot of Triton experience
AnswerID: 528863

Reply By: Crusier 91 - Saturday, Mar 22, 2014 at 10:41

Saturday, Mar 22, 2014 at 10:41
Set up depends on what type of terrain you will be tackling.
My 80 series used to sag when loaded 3Ton. We do fairly heaving off roading so the suspension is set to suit that (2" OME Nitro with OME 400kg constant rear springs and offroad poly bushes all round) no need for air bags.
The set up is a compromise as set up is a bit on the hard side when travelling on the bitumen.

Places like ARB should ask you what sought of weight you carry when touring, what type of off road terrain you will be driving, then they calculate the suspension set up you require.

Most important, like anything to do with 4wd's, dont compromise on quality and reliability, its not worth the hassle of having failures in remote locations.

Also try to find a dedicated off road Triton web site, you will get the right info straight from those how have done it.
AnswerID: 528865

Reply By: KevinE - Saturday, Mar 22, 2014 at 10:54

Saturday, Mar 22, 2014 at 10:54

I'm not sure if it's relevant to your situation or not, but I had helper springs on a work Ute with an alloy tray once. I put them on because the back used to sag quite badly with a moderate load on.

They worked great to eliminate that & they also certainly reduced body roll when cornering, but when traveling in it with no load on board the ride was so rough, you'd swear the Ute had square wheels!
AnswerID: 528867

Reply By: Ross M - Saturday, Mar 22, 2014 at 10:59

Saturday, Mar 22, 2014 at 10:59
G'day Daryl

A Triton from new doesn't have good shockers and they are usually non effective after just a few km from new.
That means the springs are then hammered more that they need to be and the spring gets fatigued.
Bellows will push up in the centre of the chassis where it really isn't designed to take a chassis bending force.
IronMAn, sounds impressive doesn't it, Load Plus only clamp bolt after the axle and rely on trying to bend the spring pack in order to lift a part of the leaves further to the rear and give some lift. Definitely not a fan of that.

Better spring packs suited to the ride, load use and height you want the vehicle to be at is the best way to go.

Just make sure the shockers are replaced.

I have recovered Tritons which have crashed because the all shocks on the vehicle were hardly working and that was at around 50,000km they were totally useless as shocks.
I have observed quite new Tritons bouncing along and it is obvious the shocks are not doing their job. Those vehicles are new shape and less than 20,000km
AnswerID: 528868

Reply By: Albany Nomads - Saturday, Mar 22, 2014 at 12:37

Saturday, Mar 22, 2014 at 12:37
I've got a set if those ironman half size helper springs on my 2004 rodeo and I reckon they great
They fit to the upper rear leaf so don't hang lower they fit to the top spring
As said verrry happy them
AnswerID: 528876

Reply By: The Bantam - Saturday, Mar 22, 2014 at 13:12

Saturday, Mar 22, 2014 at 13:12
First and most imporatnt thing to do, is load the vehicle up as it will travel, including occupants.....make sure its everything mind you.
AND put it over the local weigh bridge...make sure you get an axle split.

NOW..if one side is sagged more than the other...sounds like you are unevenly loaded.

you need to fix this.

As far as the actuall suspension uipgrade.
Yeh well airbags have been popular for a while...but not short on issues..lots of bent chassis and other issues.

as for helper springs.....AH well...what goes arround comes arround...helper springs where big in the 70's and 80s...they are what they have always been..a cheap nasty pacth for those who don't want to cough up for a full spring pack.

They have always had and always will have issues.....they may be selling some " new idea"...but nothing is new and has not been done before...still the same old same old.

As for the air bags...the last generation was the air adjustable shock absorber....yeh they where big in the 80's but seem to have disaperaed...there where some definite issues with them...same issues slight variation ...putting load on places not designed for it and a few others.

There is no substitute for keeping what you load under controll and buying a full properly designed spring pack when you need general the factory spring packs are not as good as they can be......there are some reasonably clever things the aftermarket manufacturers can do with the post bronze age leaf spring that don't come factory.

Remember iff you are not properly loaded and the weight is not well distributed a sagged rear end may be the least of your problems.


AnswerID: 528879

Reply By: Isuzumu - Saturday, Mar 22, 2014 at 13:54

Saturday, Mar 22, 2014 at 13:54
We have the 3 Stage Leaf Springs from Sax Suspension, have travelled 50,000 Ks now. Towing our camper across the GRR and Gulf and have also done about 12,000 towing our 2.5 tonne van. Truck loaded, unloaded, towing just feels the same, cost a bit more, but the old saying you get what you pay for.
PS do not have any shares in this company, may be I should.
AnswerID: 528884

Follow Up By: Member -Pinko (NSW) - Saturday, Mar 22, 2014 at 17:26

Saturday, Mar 22, 2014 at 17:26
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FollowupID: 811483

Reply By: 671 - Saturday, Mar 22, 2014 at 22:02

Saturday, Mar 22, 2014 at 22:02

How much weight do you have on this car? Mitsubishi will have specified a maximum carrying capacity but that will be for a bare cab/chassis with a near empty fuel tank. Everything that is added after that comes of that capacity. That includes the driver and passenger, whatever body or tray is fitted, the fuel and any accessories. Whatever is left after that can be added to the body/tray and that is often not as much as you think, particularly if you have fitted things like bull bars, winches, dual wheel carriers, long range tanks etc..

Many people have the rear of a dual cab dragging on the ground because, while the car may be well under GVM, they have too much out the back and a few empty seats in the front but it is not all that common with a single cab. If yours is way down then either the original springs are past their use by date or you have overloaded it. In the interests of safety and reliability, the answer should be a bigger car or a trailer.

Think very carefully before fitting air bags. Your leaf springs are linear and compress in proportion to the load i.e. if you double the load you double the compression. They just keep on compressing at that rate until the chassis reaches the bump rubbers. They bring the chassis to a sudden stop because they are exponential springs, not linear springs. The more you compress them the harder they get and the more they resist further compression.

Air bags are also exponential and will become like a rock by the time they are about 60% compressed. This is usually well before the chassis would normally reach the stock bump rubbers. As they bring the chassis to a stop, whatever is behind them will want to keep falling. All of that falling material will generate forces that increase by the square of the distance they are behind the axle and will be well above the static weight. If you doubt this then place a brick on your bare foot then drop it about 300 mm onto your foot. You will understand real quickly. This rocks the chassis on the axle and tries to lift the front placing tremendous stress into the chassis at the top of the bags. This is why so many air bag equipped cars have suffered chassis damage.

Plenty of overloaded cars have damaged their chassis without air bags just by coming down repeatedly onto stock bump rubbers or heavier rate springs on rough roads but the bags make it much easier.

You may also run into brake problems with an overloaded sagging rear end. Your car may have a brake pressure proportioning valve that increases the pressure to the rear brakes as you load the rear and the springs come down. It will reduce the pressure when the car is lightly loaded and sitting up high in order to prevent rear wheel lockup. If you overload the rear then lift it up, you may end up with a light load pressure when you should have the maximum.

it is also quite possible that heavier rear springs will alter the front to rear weight transfer ratio and place more weight onto the outside rear wheel in corners. This could easily make the car prone to going into sudden oversteer (sliding the tail out) in corners, particular if you go into one a little too fast. If you are going to stiffen the rear springs then do exactly the same to the front as well.

These are just a few things to keep in mind when you start changing the design of cars.
AnswerID: 528902

Reply By: bigcol - Saturday, Mar 22, 2014 at 23:25

Saturday, Mar 22, 2014 at 23:25
Just get Ultimate to sort it out for you.
There isn't one un-happy person on New that has their suspension fitted.

Which is more than you can say for nearly every other brand out there.

The standard suspension is absolute crap on the Triton and i'd steer well clear of air bags if you're doing anything off road and carrying anything heavy.
AnswerID: 528907

Follow Up By: 671 - Sunday, Mar 23, 2014 at 13:44

Sunday, Mar 23, 2014 at 13:44
Do they really have crap suspension or is it too many owners incorrectly loading them that is the real problem?

I have a slim 52 kg daughter who occasionally drives my 4x4 single cab. It has two big seats plus a small one in the middle. We also have two over 100 kg former NRL football players in our extended family. If I put my daughter in the front and loaded the rear up to GVM, there is a good chance that it would be tail heavy and sitting too low. If I put her in the centre seat and the two footy players in with her, I would have to put less weight on the tray to get it up to GVM but it would now be correctly loaded and sitting up the way the manufacturer intended.

That is where so many owners come unstuck. GVM means maximum weight and in order to get there correctly, every load bearing area must be fully loaded. In a ute that means the seats, the fuel tank and the tray. Few families have enough combined weight to fully load the seats so the result is often too little in the front, too much in the back, a saged rear suspension and an owner screaming because the rear is too low so the suspension must be crap.

No aftermarket suspension can safely compensate for an incorrectly loaded car.
FollowupID: 811561

Follow Up By: bigcol - Sunday, Mar 23, 2014 at 22:23

Sunday, Mar 23, 2014 at 22:23
I'll say it again.
The standard Mitsubishi suspension is rubbish.
I tow a 1.3T with a ball weight of 65kg around during the week. It has a canopy and about 25kg of gear in the rear.
Before I bought the Triton I had a BT50.
The only reason I bought the Triton was how cheap it was otherwise I would have bought a new Ranger or BT50.
When I put the trailer on the BT50 the rear would drop around an 25mm and the car would still have slight rear up attitude which is what all suspension manufacturers and vehicle manufacturers will aim for.
When I put the trailer on the Triton it drops around 65mm.
The standard shocks also can't control the suspension.
When it was new, I measured the suspension on all four corners and after 30000km it has dropped around 40mm in the rear when empty.
It has lost nearly all the rake that it should have and sits all but level.
I suggest you join and have a look through the suspension threads at the before and after suspension measurements
FollowupID: 811601

Follow Up By: 671 - Monday, Mar 24, 2014 at 14:16

Monday, Mar 24, 2014 at 14:16
It sounds like there is a problem but based on my years of experience first as a mechanic then in the service office of a couple of dealers, it is hard to believe it has not been fixed years ago.

A one off problem like yours would have had new springs fitted under warranty. The moment a dealer saw two or three of them, a vehicle product report would be sent to the manufacturer. If this is a common problem then reports would have been coming in from dealers all over the country and the manufacturer would have had a real close look at it. That did happen with Hilux front leaf springs in the mid 1980s. If any design fault was found then the problem would have been fixed.

I have seen this happen many times. One that I recall was twin cam Corollas dropping valves into the cylinders. I submitted the dealers report myself.

The best one that I heard about was one of the first 60 series Cruisers ever sold snapping a steering part out in the bush. This story came from the instructors at a Toyota factory training course that I attended on L series engines. They said the local dealer sent an urgent report to them, they immediately relayed it to Japan and Toyota engineers arrived in Sydney the next day. They were taken out to inspect the car and the roads that is was being driven on. A new part was designed and it arrived in Sydney within a week.

They don't muck around when there is a problem that can affect safety or sales.

Did you take your car back to the dealer?. If they claim it is normal or give you some other ridiculous excuse, then you ask to see a representative of the manufacturer. I have also arranged a few of those meetings but in every case the dealer was right. I would not expect that to be the case with your car. If the rep. tried to say it was normal, I would have been asking him to demonstrate how you put the maximum weight onto the tow bar seeing your little 65 kg was taking it down too far. You don't give up and run to the aftermarket with something like that.

I don't think the Triton forum is a good way to gauge the depth of this problem. The vast majority of car owners don't use them. Those who do usually think modifications first and anything else comes a distant second.

To date my only experience with Tritons is my next door neighbor's car. He has a current body style dual cab 4x4 that is now getting a few years and ks up on it. He regularly tows a lift top single axle van that looks around 16 to 17 feet long. The suspension is stock standard and he has not had any problems with it.
FollowupID: 811635

Follow Up By: peteC - Monday, Mar 24, 2014 at 18:06

Monday, Mar 24, 2014 at 18:06
bigcol is 1000% correct. The Triton rear is a shocker ( sorry ). When you own one and are doing 100km/hr on an old country road, hit a bump and it spears you onto the other side of the road you will know what I am talking about. It isnt funny. Proper rear shocks will fix some of the issues but you really need the springs replaced as well. Ultimate suspension in Sydney area, weigh the car at each wheel, discuss your use and supply and fit a tuned suspension guaranteed not to sag over time and very good warranty.

671 - in the old days dealers and manufacturers cared, they dont now. It is "Just a characteristic of the vehical"
Case 1 - why did they replace my ML steering colum 6 times between 2007 - 2010 when I sold it?
Case 2 - Why does the Triton steering when you change from left then immedialty right quickly jam up so you cant get it to turn right? Why were these issues not addressed before they released the MN range which came out with the same issues around 2012?
It could ramble about more but the reason they dont fix them is because of money and it hasnt been related to a death - Yet. Toyota has just been fined I think $2b in the US and good behaviour bond for 2 years for the same attitude.
The forums such as newtriton, newhilux, pradopoint etc is where you find much more specific information than a general 4x4 community on here ( not knocking it for what it is ) as they actually own the vehicals not know a neighbour or heard of one that owned one

Just my 2c worth
FollowupID: 811657

Reply By: Ironman 4x4 - Monday, Mar 24, 2014 at 16:09

Monday, Mar 24, 2014 at 16:09
Hey Daryl,

It really depends on what sort of driving you do and what you are looking to achieve as to what the best next steps would be.

If you plan to maintain this gear as a constant load then I'd highly recommend upgrading your rear leaf packs to something more suited to a constant load (Ironman 4x4 also do a range of uprated leaf packs).

The other thing is if you are wishing to maintain the vehicle at a standard ride height. Ironman 4x4 do a range of suspension upgrades that provide a lift of up to 40mm on the Tritons. If you want to maintain a standard ride hight but still carry more load, you're welcome to have a chat to us and we'd happily make some recommendations as to the ideal setup for you.

If you don't plan to do a lot of 4x4ing, the load plus will do a perfectly fine job of levelling out your ride for a much lower cost than replacing your leaf packs, but if you plan to take your vehicle offroad I'd suggest upgrading the leaf packs as the load plus can start slipping with the vibrations and flexing that 4x4ing results in.

If you have any further questions, you are welcome to shoot us a PM or even leave a message on our Facebook page and I'd be happy to get into contact with you.


Ironman 4x4
AnswerID: 529003

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