Parabolic Leaf Springs

Anyone have any experience with them,old technology but terrain tamer have rehashed them with modern materials etc and there getting good reviews,im thinking about throwing a set on our dmax soon,i just spent 2 days repairing busted tray mounts from corrugations etc and thinking these will help,big weight savings to,i like that......

[video=480,360]https://youtu.be/U_Y4KnF_1PY[/video]

Look good but cant help but think of the Hungry-Hippo game in the wrong ground conditions. Could double up as an emergency speci crusher though.

Every thing old is new again. Try comparing apples to apples 300kg against 500kg capacity :lol: :lol: :lol:

Wally69 said:

Look good but cant help but think of the Hungry-Hippo game in the wrong ground conditions. Could double up as an emergency speci crusher though.

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Dont know what the hungry hippo game is but are ya talking about the bottom spring getting hung up? Agree on the underhang but not such an issue for us in wa,i imagine the rock crawlers and hardcore dudes might steer clear of them.
Theres another video where they put a 1000ltr pod on a patrol and it handles the weight well,they do put it right up on the headboard on a single cab though....
Yeah sample crusher,top idea,i have a bit here to knock over

Yes GC1 - was thinking of some of the really rough terrain I have been on, the beenthereandshouldnthavedonethat marks on my landcruisers undercarriage and that yawning front facing spring gobbling up sticks, fly rock, chunks of the trail and spun up mud and sand.

Once in there, as rare as it may be, I imagine it would just work its way down towards the axle or be a real bother to extract.

Suspension is a very broad topic to define.
I personally don't like the idea of having the lower leaf open .
With pinch points opening and closing at every bump etc....
The extra shackles need to work overtime and would become prone to wear easier than stock arrangement.
Suspension options vary heaps.
Up to individual requirements to select the correct pack.
From what I have gathered...
Eg, a vehicle is fitted with stock springs rated at 500kg . That's gives a certain ride hide measurement of eg (500mm) ...
Stock springs are usually designed to give you bit of comfort over the equation over load capacity.
Now leafs have a general rule of measurement, eye to eye of the main leaf, and measurement of a straight line , eye to eye down to the top of the main leaf. ( basically measuring the radius).

* If one was very happy with the stock pack, and feel etc. Yet simply wanted say a 2" lift. There is a couple of options available.
# Longer shackles on original springs.
# new leaf pack made up with with same load rated springs as stock, yet the radius is increased by 2"s,
Same ride feel in and load with Suspension as stock generally

* if one wants to keep the ride height stock, but beef up the load capacity.
*#Up grade leaf thicknesses (mm) in the pack. This will generally affect the feel, Harder ride, especially when unladen.
# Add a leaf. Adding a lower leaf generally doesn't affect the stock feel or ride height unladen.but assists the packs radius when loaded. Not a great overall improvement for the effort.
#air bags

*How do you get both? Extra height, load capacity, whilst still maintaining some comfort when driving unladen....
# Air bags.
# custom packed springs combination. Cheaper and easier than you think! There are Aussie companies that make springs to order, or tailor with your exact needs.

Take a stock 7 pack of leafs. They might be all 6mm thick, and generally descending in length each by 120mm each. Getting shorter etc.
Your first 3 leafs take the brunt of stock weight and bounce.
* options.
# they will gladly fit another/extra leaf in under your main leaf . Almost the the same length. Slightly higher ride height and harder feel.
# + adding extra radius to them. Increase in height.
# leave first two leafs in stock thicknsss ( comfort) then increase leaf thickness for the rest of the pack. Aiding when laden.

So there is numerous combinations available. Depends on your needs.

Things to consider are ..
# legal lift height in your state.
# legal with your insurance company
# Rear driveline alignment! ( can happen when you change the angle of the rear diff pinion to the rear transfer case, vibration and premature uni joint wear. Angled shims may need to be fitted to realign the correct angle.
# brake lines long enough.
# Shock absorbers struts long enough.

Up front, coils.
You might find springs that offer a 1" lift over stock. But if you have a steel bar and winch on. This will bring it back to stock height.
So a 2" lift spring with a steel bar and winch will give you a 1" lift.

Remember, shock absorbers themselves are not a means of lift etc, unless your are referring to air shocks.
A secondary pair of air shocks i have seen fitted to assist. But air bags would win over in the long run.

Some good info there MH,alot of suspension companies wont go above 30-40mm on the ifs front ends now,to much hassle,cv angle and camber adjustments can get tricky.....
Wally im hearing ya,we have 4-5 79 dual cabs at work,2 of them have parabolics and have been bashing around a minesite for 250,000 klms now,,they ride well,i cant see a build up of mud etc in the leaves,and they are caked on occasion when it rains,had a squizz last night at one it looks ok,only drawback i see is the underhang,could be worse if ya got leaves up front as ya say.
Fitted a 2 lift to our dmax when i got it,i ordered 600kg constant rears but pulled the extra leaf to take them back to 300 s so i had options but now with our camper- quad and all loaded up she sags to much,just havent had time to pull them and put the extra leaf back in,not lookin foward to the ride unloaded either.
Bit of a conundrum as threw winter we take off loaded up constantly but from now on its day trips out bush mainly all summer,rides a bit rough and with the extra spring back in well hang onto ya dentures.....

Old technology made new again.

This brings to mind a diagram that I was taught about a few moons ago.
Involved a set of leaf springs with red arrows pointing at the load points on the middle and on each
spring shackle and eye plus one aimed rear wards..

To improve our old HR Holdens and such, Nothing beat a set of " Helper " leaf springs fitted.

Mainly on the front section facing forwards. This was to stop any lateral oscillations encountered when
applying heavy right footed emplantment when required. (Tramp Rods )

When you went the full hog, An extra heavy duty spring was fitted on both leading and trailing area's of
the rear spring pack was engaged. This was to stop any chance of the diff snout both kicking both forwards and
backwards.

We also noticed that when the boot or Holden Panel Van was loaded down with the necessary supplies for a weekend away,
The ride was so much more better that fitting Air Shocks. Yes, I know, We did have a separate air line on each one.
And bent a few stock rear shackles working it out.

That is why I cracked the back chassis rails in me HD.

They just could not handle the load points on them.

Tathradj said:

Old technology made new again.

This brings to mind a diagram that I was taught about a few moons ago.
Involved a set of leaf springs with red arrows pointing at the load points on the middle and on each
spring shackle and eye plus one aimed rear wards..

To improve our old HR Holdens and such, Nothing beat a set of " Helper " leaf springs fitted.

Mainly on the front section facing forwards. This was to stop any lateral oscillations encountered when
applying heavy right footed emplantment when required. (Tramp Rods )

When you went the full hog, An extra heavy duty spring was fitted on both leading and trailing area's of
the rear spring pack was engaged. This was to stop any chance of the diff snout both kicking both forwards and
backwards.

We also noticed that when the boot or Holden Panel Van was loaded down with the necessary supplies for a weekend away,
The ride was so much more better that fitting Air Shocks. Yes, I know, We did have a separate air line on each one.
And bent a few stock rear shackles working it out.

That is why I cracked the back chassis rails in me HD.

They just could not handle the load points on them.

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Yep, Regardless of what the advert Blurb says, going from 300kg to 500kg is real crazy, In order to avoid Cracking Chassis Mounts and Spring Mounts the increase in weight ratio should not be more than 10 to 15%, So going from a 300kg spring to a 330/345kg is the safe limit unless you are going to get all new mounts fitted and Plated, WHY ??

Well how many pictures have we seen on here with modern Utes with bent Chassis, By increasing the spring weight by up to and over 40% is almost Guaranteeing the Chassis is going to fail, It does not Matter what a Mate says or has got on his truck or what the dealer says, Sooner or Later It's going to break like it or not, This is why they have a factory rating, Remembering that modern trucks are not as tough as the ones that came out in the 70's and 80's because now they have thinner Chassis and Crumple Zones these come at a cost of Strength and Rigidity, And by fitting springs like this if they can't flex then the Chassis will.

I had wondered how new utes were made, just hope mine isnt the underside variety....

The Chassis on Trucks in the 70's and 80's were deeper from the Front of the forward rear spring Hanger, F-100's Chassis were C Channel about 7"x 2 1/2" in size and most 4x4's were 5 X 2 1/2" or 6 X 2 1/2" Boxed section which is why they could take the bashing and the weight, Where as Modern Trucks Chassis measure around 3 X 2" to 4 X 3" (100mm X 75mm) and to save weight the wall thickness is a lot thinner,

If you look at those pictures all 3 Trucks have bent just in front of the Rear Spring Front Hangers or in the case of the Hi-Lux Camper it has bent just in front of the Middle Door posts Under the rear of the front Seats, The Rear Spring mounting points are not the issue because the loaded weight is transferred to the Mid Chassis Point, Add a Heavy Bullbar and a Winch on the Front might compress the front Springs a bit but that weight is also transferred towards the mid point of the Chassis somewhere between the front and rear seats,

The Older Trucks you could use the 10% Hitch weight and never have an issue but these newer Trucks can't handle the heavy hitch weights of a lot of modern Aussie Campers and Caravans, Remembering that the Hitch weight of the Trailer has to be deducted from the permitted load for that vehicle, In picture 1 the Nissan springs have very little curve left in them which says that it is at Max load maybe more ??

J.

"Where as Modern Trucks Chassis measure around 3 X 2" to 4 X 3" (100mm X 75mm) and to save weight the wall thickness is a lot thinner,"

Don't know what tape measure you are using RR but the chassis on the trucks here (Kenneth's and Isuzu) are about 10 " x 4". Shopping trolleys are not trucks and if loaded and driven correctly will not have a problem.

Cheers

Doug

Rockhunter62 said:

"Where as Modern Trucks Chassis measure around 3 X 2" to 4 X 3" (100mm X 75mm) and to save weight the wall thickness is a lot thinner,"

Don't know what tape measure you are using RR but the chassis on the trucks here (Kenneth's and Isuzu) are about 10 " x 4". Shopping trolleys are not trucks and if loaded and driven correctly will not have a problem.

Cheers

Doug

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Any Vehicle that has a separate Chassis is Classed as a Truck Chassis regardless whether it is a SUV or a Ute/Pickup, No where in this thread has anyone Mentioned Kenworth Sized Trucks, And I don't recall any Truck with a 10x4 Chassis coming fitted with 300kg Springs.

So get over your ego and stop dragging another thread through the Mud.

Stop calling SUV's and 4x4's trucks RR. Someone has to keep you inline seen Madtuna doesn't have a go at you now.

Cheers

Doug

Rockhunter62 said:

Stop calling SUV's and 4x4's trucks RR. Someone has to keep you inline seen Madtuna doesn't have a go at you now.

Cheers

Doug

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No because they are Truck's, You don't get to dictate to me, I don't care what your views are, It's a fact that Cab on Chassis vehicles are Classed as Trucks,

Thanks RR for turning this thread into ya own little dramatised agenda,by the way some of us have real world experience travelling the outback loaded up for years,what ya posted is old news,its called load distribution,to much weight behind the axle is there main problem,not heavier springs,if ya havent got any experience with parabolic springs please sod off.....

Done a little research last night Dave and Western Australia Springs I think it was said that there is no one in Australia making parabolic Springs, they were all imported.

Cheers

Doug

"All parabolic springs in Australia (including Westralia Springs) are manufactured overseas. It is not possible to manufacture parabolic leaf springs in Australia as the high chromium steel is unavailable and there is no Australian spring maker with a parabolic tapering machine. Westralia Springs are the leading designers of 4wd parabolic springs and have been supplying parabolic springs to the 4wd market for over 30 years. Our parabolic springs are designed to be uprated & raised height when compared to genuine springs. As our parabolic springs are manufactured overseas to our drawings it is not possible to get special custom one off springs made"

Found it.

Cheers

Doug

I found Dobinsons at Rockhampton branch really easy to talk to for customised configurations.
https://www.dobinsonsprings.com/index.php/suspension/springs/leaf-springs
Worth a look at chat before committing.
This branch is the factory for Australia im quite sure.
My knowledge is vehicles have a defined gross weight carrying capacity.
And you can't go past/over it without an engineers certificate.
But stock springs in most ( carrying/ towing ) vehicles are designed to give you a reasonable pleasant ride unladen.
( the ride in a dump/ tipper truck empty is bouncy, yet a better ride in the truck laden)
A vehicle that is going to constantly loaded / towing will keep a better balanced ride height when fitted heavier springs period!
But you will have a much harder ride feel empty.
The " parabolic " configuration is designed to give you a bit of both worlds.
There are similar designs using even thicknsss like leafs.
Cracking one leaf isn't great, but can be fixed on the side of the road if not the main.
Relying on one spring alone could be risky

Rockhunter62 said:

Done a little research last night Dave and Western Australia Springs I think it was said that there is no one in Australia making parabolic Springs, they were all imported.

Cheers

Doug

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Yeah ive read about them for years doug, westralia were the only mob doing them for cruzas or early patrols for a long time,im talking 15 years maybe ive read a few bits on there ones.
The old feedback was there great but terrible for loads,alot of guys are running the new terrain tamers or west oz ones on 79s with good reviews now,we were thinking of ordering a 79 next year (canned that atm)so ive been on a few cruza sites,most say its the best thing theyve put on there trucks.
Ive been reading as much as possible on them,i think its apm or apd in malaysia thats supplying the springs,terrain tamer will popularise them so i think theyve put alot of work into designing the current ones hopefully and a bit of clever marketing to boot. Also im sure this is the 1st time ya can get them for the ifs utes.
Bad luck with the old HD tathra,there saying they reduce stress on the crown wheel and pinion to,similar to what you mentioned above,no engineer here but i guess its less shock transfered through.
I think a few are getting on the bandwagon MH,dobinsins im sure i read of supplying them now and maybe efs,.
Incorrect info posted above also,theres nothing wrong with 5-600kg spring packs,there not all gonna snap chassiss eventually as indicated,dual cabs overloaded behind the rear axles and bad terrain is the main culprit,commonsense prevails....