Parabolic leaf springs

[tony]

Does any have any expperience with parabolics & know prices or the best place to source? Any pros & cons would be appreciated.

Thanks.

Panda

[JDNSW]

I don't have any personal experience, but I don't know of any cons - the only catch I've heard of is that some have failed, apparently the cheaper ones - but then conventional springs break occasionally anyway.

Note that you need dfferent shock absorbers for the parabolics.

I would fit them to my 2a if I could afford it!

John

[tony]

I don't have any personal experience, but I don't know of any cons - the only catch I've heard of is that some have failed, apparently the cheaper ones - but then conventional springs break occasionally anyway.

Note that you need dfferent shock absorbers for the parabolics.

I would fit them to my 2a if I could afford it!

John


I had no idea you need different shockies. Guess I'll have to put the leaves & shockies on my wish list.

I was readiing an LRO mag last night & saw some advertised for 199 pounds, hence got me thinking. Some of my leaves are broken & would love to replace them with paras. Maybe if I start saving now ... that is of course providing nothing else major breaks in the meantime!

Panda

[lro11]

I have just purchased a set for my series 3 ute they cost a bomb. the only bad thing that I have heard is that they are no good for towing. I have not used mine yet look at this website it helped me Rocky Mountain Parabolic Suspension (http://www.parabolicsprings.com/) I bought mine from FWD

[tony]

I have just purchased a set for my series 3 ute they cost a bomb. the only bad thing that I have heard is that they are no good for towing. I have not used mine yet look at this website it helped me Rocky Mountain Parabolic Suspension (http://www.parabolicsprings.com/) I bought mine from FWD


Thanks for that. I'll check it out. Let me know what they're like when you take her out.

Panda

[olmate]

Tony,

I have had Rocky Mountain Paras on mine for a while now and they have been great; better ride and articulation etc. Went for the Pro-Comp shocks with the set-up and have been very impressed. Also I decided on the 3 leaf rears for my SWB as I carry a bit of kit and 'tow' - no problems to date. Mind you - If I take the crap out of the back of the girl the things sits up high.....:o

You can also get OME shocks if you wish. Talk to FWD as they are a real help.

My profile pics do show some pics of the set up if you wish to take a look.

I also went for longer brake lines as the old ones were on the way out and it was quite cheap to have custom ones made.

[DiscoDave]

My S1 has parabolics and it rides a lot smoother than my 109... but then I guess that's not saying much! ;)

[Panda]

Did a bit of investigating ... my God they're expensive:o

Unfortunately, will have to wait awhile til I'm more financial. The whole kit costs more than the old girl's worth! Thanks for everyone's input.

[DiscoDave]

I've recently taken my Series 1 down a very bumpy and potholed road, the kind of road you think about using low-range on, and was amazed at the difference between it's ride and the 109's. In the 109 I would be thinking about the chiropractor's bill, wishing I had a neckbrace and wondering if I would make it out before my teeth shattered. In the Series 1, although not pleasant, it was nothing to worry about. I'm guessing a lot of this difference is due to the parabolics on the Series 1 although the 109 does have an awful lot of plates in the rear leaves and is designed to carry 3/4 ton payloads so perhaps it's not a fair comparison? ;)

[lro11]

does anyone know if you can still fit the axle strap with these springs mine sits a bit higher but I dont have any weight on it yet?

[Cliffy]

If you can afford them...get them!! They are ace!Had them on my SWB SIII and dare I say, almost like coils!

[Mrlandyman100]

G'day,

I am not sure if any one sells them in australia... (maybe in WA I heard of some one selling them) But I know that a few years ago TI Console used to make a 2 leaf parrabolic spring and a extra one under it that would only be doing any thing when there is a load in them. Has any one heard of them?

Cheers:)
Ben

[LandyAndy]

Lots of people say they are no good for carrying weight in a 109.
Suerly a set of airbag helpers(similar idea to the coil airbags) would fix the problem.Would fix the towing problem too.
Andrew

[olmate]

does anyone know if you can still fit the axle strap with these springs mine sits a bit higher but I dont have any weight on it yet?

Rocky Mountain provide you with the correct axle straps for the veh / setup that you purchase. No probs there.

Just dont buy the cheaper ones. If they work -my research suggests that you will only get about 12 months out of them; hence spending more money for better quality (Rocky Mountain). As for shocks - Pro Comp have been great. Rocky Mountain do offer OME but I stayed away from these after issues in the past and negative reports form other users.

All I can say is - if you want the paras be prepared to spend some cash... but the difference is outstanding, loaded or unloaded. :D

[Bisho]

so how much is a lot troy? or is that classified information! if only the mrs knew eh.

[isuzurover]

Rocky Mountain provide you with the correct axle straps for the veh / setup that you purchase. No probs there.

Just dont buy the cheaper ones. If they work -my research suggests that you will only get about 12 months out of them; hence spending more money for better quality (Rocky Mountain). As for shocks - Pro Comp have been great. Rocky Mountain do offer OME but I stayed away from these after issues in the past and negative reports form other users.

All I can say is - if you want the paras be prepared to spend some cash... but the difference is outstanding, loaded or unloaded. :D

Fitting check straps defeats the purpose of fitting softer springs IMO...

I threw my check straps away when I rebuilt my IIA in 1995. I have taken it offroad heaps of times since then, and in 1998 I fitted custom springs that give me about 15" of wheel travel front and rear - with no problems. OK - I snapped the eye off a front shock once, but it was probably old and weak, and I just welded it back on.

If anyone doesn't want to spend the money on paras, you can build custom semi-elliptic springs which won't quite be as comfortable on-road (but much better than standard), but will be as good or better off-road. If there is any interest, I will dig up the thread I posted on mine.

This is a long way from full travel.
https://www.aulro.com/afvb/
https://www.aulro.com/afvb/

[Bisho]

ben i'm interested mate! how did u do them? i'd LIKE parabolics, but alas, they are a lot of dosh. i'm also interested in doing some touring down the, have u done much with your springs? are they just cut down? cheers

[dolphint]

Thanks Ben, looks awsome!! I'd be interested in getting more info:)

[isuzurover]

ben i'm interested mate! how did u do them? i'd LIKE parabolics, but alas, they are a lot of dosh. i'm also interested in doing some touring down the, have u done much with your springs? are they just cut down? cheers

Hi Bisho - Have I done much touring you ask... ;):D

Have a look here...
http://www.aulro.com/afvb/general-chat/48992-bris-perth-so-far-so-good-3.html

On page 3 of the above is a post I cut and pasted from Outerlimits (also below). It is a bit terse/short, so let me know if you want/need more info:

Note - since posting this I think there is a bit more room to move on SWB springs - the SWB I built for my Dad had VERY soft springs, but I think that wasn't typical. If you let me know what spings are fitted (number of leaves and thickness) to each corner of your landie, what body style, any mods, and what you want to use it for, I am happy to advise what I think would work.


Front.
The best front springs are the std 9leaf SWB petrol springs (200lb/in) - these have one 4.4mm main leaf and 8 4.2mm leaves - it is hard to find a good second hand set. They will work on all LR's except a 3.9 ISUZU. If you have these springs just cut a taper in the leaves, smooth up the edges and that is all. I didn't have these so I bought after market SWB petrol spings that have 9x5mm leaves so the rate is 315lb/in!!! - I removed 3 leaves (so now 6), tapered and smoothed the edges and had them reset to about 11" free camber (drivers) and 10.5" passenger. If you have a military LR, remove the bump stop spacer but retain the std shock. If you have a civilian LR, you can usually get a lot more up-travel than the bump stop will allow. I know people who have cut the bump stop in half, but you can also relocate the shock mount higher and fit longer shocks.

Rear.
For a SWB - again the std factory leaves are best - should be 11x4.4 (longer leaves have a lower spring rate) with a rate of 160lb/in. Again if you have these, taper the leaves.
For a LWB - you want a rate of about 270lb/in. I had std military 8x7.1mm springs, which are 400lb/in. (S3 9x7.1mm are 500lb/in!!!). I removed 3 leaves (now 5), cut the rest down to an even spacing and tapered them. And had them reset to about 14" drivers side and 12" passenger. All it cost me was $60 a pair to reset - make sure they temper them after resetting. They will settle a bit after you have them on the truck, that is why the free camber is so high. You could go a bit softer but 270lb/in still lets me carry a decent load as well.
For a military truck, leave the rear bump stop spacer in and fit Range Rover rear shocks. For a civilian, RR shocks would work as well but you need to raise the shock mount (and have to cut a hole in the floor for space).

You will get increased on road comfort with this setup, and more body roll, but the truck is just as stable when cornering, and you get used to the body roll. If you have an engineering background, grab a book called the "leaf spring design manual" by the SAE. It is what I used. But if you just follow the steps above you won't need it.

EDIT - make sure the guy resetting your springs tempers them after the reset, as they won't hold their set as well as if they are set cold.

I originally posted some pics to accompany this info, (but they have been lost from the original thread) so if anyone wants I can dig them out... and repost them

Outer Limits 4x4 Board :: View topic - Parabolic results with standard springs? (Series Leafer Cont (http://www.outerlimits4x4.com/phpBB2/viewtopic.php't=21683&postdays=0&postorder=asc&highlight=custom+springs&start=0)

Outer Limits 4x4 Board :: View topic - Parabolic springs... (http://www.outerlimits4x4.com/PHP_Modules/phpBB2/viewtopic.php't=18823)

[Lotz-A-Landies]

....This is a long way from full travel.

I think that is outstanding articulation on leaf springs - why would you go to the trouble of re-engineering a series vehicle with coils when parabolics can do that.

Note to self: Must put pennies in piggy bank for new RMP's

Diana

[isuzurover]

I think that is outstanding articulation on leaf springs - why would you go to the trouble of re-engineering a series vehicle with coils when parabolics can do that.

Note to self: Must put pennies in piggy bank for new RMP's

Diana

Thanks Diana, however those aren NOT RMPs. They are custom Semi-Elliptics that I built myself. I have never seen a parabolic-equipped vehicle which gets comparable travel (apart from one guy in the UK who uses whacky-shackles and rotating spring hangers).

Parabolics are actually surprisingly stiff in terms of spring rate. What makes them comfortable is the lack of interleaf friction. This means that a parabolic spring behaves like a coil over short amounts of deflection/travel (i.e. can move rapidly to soak up bumps). However, for serious wheel travel, a parabolic is inhibited by the thickness of the leaves, as the stress between the face of the leaf which is in compression and the face in extension is much greater for a thicker leaf than a thin one.

Btw - parabolics are correctly termed "single leaf springs" - or at least they are in engineering design manuals. This is because each spring is unaffected by the others in the pack. They are also still semi-elliptic in curvature, the taper in the leaf is the only parabola.

[olmate]

so how much is a lot troy? or is that classified information! if only the mrs knew eh.

John,

Sorry that it has taken me a long time to get back to you. My Rocky Mountian setup cost $1800. And yes - the missus did spew when she found out. :D

[cjc_td5]

"...If you have these springs just cut a taper in the leaves, smooth up the edges and that is all. I didn't have these so I bought after market SWB petrol spings that have 9x5mm leaves so the rate is 315lb/in!!! - I removed 3 leaves (so now 6), tapered and smoothed the edges and had them reset ..."

Isuzurover,
Please excuse my ignorance, but what do you mean by "taper" the springs? (Is this cutting them to length so that they taper down evenly from the longest leaf, or something else???)

Thanks

[isuzurover]

"...If you have these springs just cut a taper in the leaves, smooth up the edges and that is all. I didn't have these so I bought after market SWB petrol spings that have 9x5mm leaves so the rate is 315lb/in!!! - I removed 3 leaves (so now 6), tapered and smoothed the edges and had them reset ..."

Isuzurover,
Please excuse my ignorance, but what do you mean by "taper" the springs? (Is this cutting them to length so that they taper down evenly from the longest leaf, or something else???)

Thanks

Hi Chris,

Not exactly - Another word would be chamfer. Spring leaves with square cut ends (a-la standard landie) have a higher "stiffness factor" (engineer speak) than those with tapered chamfered ends (the corners chopped off diagonally). Hope that makes sense? Basically you want to make it so the ends of the leaves will slide forwards and backwards smoothly.

e.g. see here: The leaf closest to the main leaf is chamfered/tapered, the next one isn't.
https://www.aulro.com/afvb/images/imported/2008/03/461.jpg

[isuzurover]

I have dug out some pics of my setup for anyone who is interested. NOTE - I hadn't yet cham,fered/tapered the leaves in these pics.

Front compressed (not yet full travel - compresses bump stop about 1.5" on fill travel) - note this is a military chassis with the bump stop spacer removed (rear still in place).
https://www.aulro.com/afvb/

Rear Springs - yes the inner clamps are ridiculously long - I shortened them later
https://www.aulro.com/afvb/

One new rear and one old rear fitted:
https://www.aulro.com/afvb/

Rear compressed (also not all the way):
https://www.aulro.com/afvb/

[Ruski73]

This is useful information. I'm about to embark on a suspn project. I'd prefer to keep the bog standard leafers for budget reasons. I think one leaf has been taken out of each of the rears by the previous owner and it's a but saggy. If I can find a torch I'll go out and count 'em. I'd like to get the rears reset without adding leafs. I suspect the front is untouched. It is as stiff as a board. Can I remove leafs from front? I need new shockers too. What sort should I go for ... ??

[isuzurover]

Glad the info was helpful.

First thing is to measure EXACTLY what you have (number of leaves and thickness), and check condition (good / rusty and spreading, etc.).

If you have genuine springs, the leaf counts and thicknesses should be the same as here:

https://www.aulro.com/afvb/images/imported/2015/01/984.jpg
(thanks Diana)

There is no reason you can't get the springs reset (AND tempered) without adding leaves. You can also pull leaves out if you have a very light landie or aftermarket (thicker) springs.

[sclarke]

Reading all of this has made me excited about my new purchase...
Need to see What DaveS3 did to the Stage1 in the springs....

[stirlsilver]

This does indeed look really good!!! What forums are all about!!! isuzurover... that is fantastic information you are sharing there and I am seriously considering doing the tapering of the leaves as you suggested. They are aftermarket leaves though... I might see if I can borrow that leaf spring design manual from somewhere as I have an engineering background and see what I can come up with!

[andies landies]

I've got a Ti-console set on my stage one and recently fitted a set of Rocky-Mountain ones to a Series II SWB and both work well, correct shocks are vital, I had the pro-comp set that came in the rocky-mountain kit on the stage one and they worked better than the ome ones on it before but now I've got rancho adjustables and you can get some amazing smoothness as long as you adjust to suit the load.

With the pro-comp and probably rancho shocks you need to regularly check that the boots are draining. I had to replace mine cause the boots were holding water and rusted the shock around the seal, letting the gas out!!

Andrew

[isuzurover]

I suspect the front is untouched. It is as stiff as a board. Can I remove leafs from front? I need new shockers too. What sort should I go for ... ??

If the front is stiff as a board I suspect you may have aftermarket springs. SWB fronts are generally not too bad unless rusty.

What shocks you go for depends on what setup you end up with. With the stock 9/10/11 leaf springs, you have lots of interleaf friction, so you will barely notice whether you have shocks fitted or not - believe me - I drove 400 km home (and 2 days of 4x4ing beforehand) with the front right shock removed (snapped the eye off offroad). Didn't notice the difference. But with fewer leaves (thick semi-elliptics, parabolics, etc) your shocks need to do much more work.

Shocks on a leafer generally only work in extension, not compression (I think they are called 2-way shocks?). Shocks for a coiller usually work in both directions (I think they are called 4-way).

I still have the original military shocks on the front (old-school monroe - when they were good!) which I had reconditioned by WW shocks in Brisbane.
On the rear I have OME Range Rover rear shocks - these are 4-way shocks. You can only fit these if you have a military chassis, otherwise they will be too long. I am not too fussed with OME quality (got them because they were very cheap), but they have done the job fine so far (on started weeping oil fairly early on).

Even when you only have a few leaves, you still have a fair bit of interleaf friction, so ANY reasonable quality shock of the CORRECT LENGTH will do the job (but if you have 1-6 leaves in each pack I would go for a coiller shock in preference).


This does indeed look really good!!! What forums are all about!!! isuzurover... that is fantastic information you are sharing there and I am seriously considering doing the tapering of the leaves as you suggested. They are aftermarket leaves though... I might see if I can borrow that leaf spring design manual from somewhere as I have an engineering background and see what I can come up with!

Stirling - thanks - glad people are finding this useful. I posted a long reply but the website crashed on me !!! will type it up again later when I have time.

[stirlsilver]

After reading your posts here and on outerlimits4x4 I decided that I had too many leafs in my rear packs (7mm x 8) when my car is a cab chassis with an alloy tray! Waaay oversprung. So at 9pm last night I got underneath and pulled out the 3rd leaf... took me a couple of hours to do both sides. I should have taken out the second leaf to maintain the even stepping of the individual leafs but it had the military wraps and I didn't want to pull out the bolts in the bushes.

I'm gonna have to take a good look at my suspension, pull out some leaves from the front and get them all reset a little higher and tempered and see how that all goes.

So in the current config it isn't ideal but oh my god did it soften the rear a lot, I can now compress the rear by pushing down with my weight! And I did originally want to take out two leaves but found that my centering bolt was too long!

Anyway I took a look at that Leaf spring design manual by SAE in the library, pretty comprehensive and pretty much tells you how to design the packs from the ground up! It was interesting to note that having leaves with blunt ends is the worst configuration. Chamfering is next best and then there was two other cofigurations that looked like the tips of a flat bladed screwdriver.

Anyway I'm heading out to do some offroad work tomorrow with some of the other guys on the forum, it will be interesting to see how it goes now as before it was the rear which was sorta letting me down in the articulation deparment.

Also, on the rear I have these two big rubber bump stops about 150mm long, are these after market or original items? Does anyone know? Was tempted to pull them out also but I figure I better check how close the tyre comes to making contact with the bottom of the tray (running 33" tyres) and If my shocks can compress all that way also.

[Ruski73]

The official count is 7 in each side front and 8 in each rear.

[isuzurover]

The official count is 7 in each side front and 8 in each rear.

Which model landie?


Stirlsilver, there should be a couple of big rubber bump stops in there front and rear - would have to see a pic of yours to see if they are factory or not.

Glad youa re happy. I would never remove the 2nd leaf, it is a great safety factor in case the main leaf dies.

[stirlsilver]

I'm now actually eyeing off parabolics... $1,600, geez they are expensive... hmm maybe in a couple of months... It's always hard to justify purchase for the car that is the same or greater value than the car!

[Ruski73]

Which model landie?

Bog standard Series 3 88"

[isuzurover]

Bog standard Series 3 88"

Not quite. See the page from the SIII manual on p3. 9 leaf front and 11 leaf rear is factory.


Stirlsilver NOOOOOOOOOOOOOOOOOOOOO Don't do it - not now you have started with custom springs. Paras may be (a bit) more comfortable, but with custom semi elliptics you can get exactly what you want.

[JDNSW]

....... I should have taken out the second leaf to maintain the even stepping of the individual leafs but it had the military wraps and I didn't want to pull out the bolts in the bushes.

...........

Not quite sure why you call them military wraps - as far as I know they are standard on all leaf spring Landrovers.

John

[101 Ron]

The 101 landy has a parabolic set up from the factory and they are set up for carrying a payload.
The interesting thing is these springs work best at small defections like corrigations because of the little interleaf friction,but they dont have the off road flex of normal springs.
I personally would rework the leaf pack and reset the original leafs if they are in good nick.
If you have a ex army 2a one of the best things you can do is take a few leafs out (experiment) to reduce the spring rate as the miltiary always set the springs up for over load.
I found some landys like the stage one V8 wagons are very good from the factory.

[isuzurover]

Not quite sure why you call them military wraps - as far as I know they are standard on all leaf spring Landrovers.

John

That is the common term for the double-wrap - because apart from LRs, that style of 2nd leaf is usually only used on military vehicles.

But you are right - all landies have them - one of the great ideas that LR had.


Ron - agree 100%

EDIT - btw - for anyone who is interested (and has a basic maths/engineering background), a simplified leaf spring rate equation is:

r = (w.n/12) * (t.1x10^3/L^3) * SF

Where:
r = spring rate (lb/in)
w = width of leaves = 2.5" for all SII/IIA/SIII
n = number of leaves
t = thickness of leaves (when spring packs have different thicknesses - need to calculate a few times for each group of leaves of the same thickness)
L = length of MAIN LEAF - eye to eye, with the main leaf completely flat (See SIII manual a page or two back for those values)
SF = stiffness factor (basically a fudge factor to get the equation to fit real results) - for square cut leaf ends SF = 1.1 - 1.3

If anyone is interested I could put this up into an XLS spread sheet/macro, so people can use it to design their own springs.

[stirlsilver]

Knowing the spring rate of your packs is good info to have. But the thing that has me hung up is the actual dead weight that the springs have to carry and working that out... Otherwise it will be difficult to tell what height the car will settle to when you put in your newly tuned leaves that have been reset to a custom free camber. It's really something that has to be measured, but for that you need some real big scales! Or do you...?

[isuzurover]

Knowing the spring rate of your packs is good info to have. But the thing that has me hung up is the actual dead weight that the springs have to carry and working that out... Otherwise it will be difficult to tell what height the car will settle to when you put in your newly tuned leaves that have been reset to a custom free camber. It's really something that has to be measured, but for that you need some real big scales! Or do you...?

Actually I found the free camber values the easiest to work out.

While weighing each corner would be the best option, you can use the free camber values in the S3 manual to extrapolate what your custom springs need for a free camber. There is a free camber equation in the SAE design manual.

I did the rear first, and they sagged/settled a bit, but I think that was because I had made the upper stage slightly too soft first time around, AND the spring place didn't temper the springs after resetting. Still, they worked fine for a year or so antil I could be bothered pulling them out (did the fronts at the same time). The fronts worked finr first go, and have been in the car since 1998, same goes for the 2nd iteration of the rears.

When I got the fronts done (and the 2nd iteration of rears done) I added 1" to my calculated free camber values, to allow for any slight settling which might occur.

[stirlsilver]

I would imagine one problem with the amount of free camber that you use is that if you go too far you may find that you will have a problem with shackle inversion? Maybe not so much a problem with the front but It looks like it could happen on the rear.

I'll have to go back to the library and photo copy some pages out of the book. The book did have some pretty heavy duty equations in there, and I didn't have time to sift through which ones were the most relevant. Also, the drawings which were supposed to illustrate the axle path was nuts!

[isuzurover]

I would imagine one problem with the amount of free camber that you use is that if you go too far you may find that you will have a problem with shackle inversion? Maybe not so much a problem with the front but It looks like it could happen on the rear.

I'll have to go back to the library and photo copy some pages out of the book. The book did have some pretty heavy duty equations in there, and I didn't have time to sift through which ones were the most relevant. Also, the drawings which were supposed to illustrate the axle path was nuts!

I didn't have any problems with shackle inversion. I think landies aren't prone to this - unlike cruisers!!!

My driver's side front spring had so much free camber when I got it reset, that I had to use a chain and hi-lift off the back axle to flatten it ouit enough to connect the shackle up (no load on spring). Once the weight was on it everything was fine though. It never inverted on me. I have never seen an inverted rear either.

[stirlsilver]

:twisted: I like how this all sounds. Especially since the camber helps out with how far the axle is able to move down. Great info you are providing ben! I'll probably use your free camber measurements then since they seem to have worked quite well for you.

[stirlsilver]

Ben, is that equation you provided correct? I just tried to use it and it is producing very small values. I just checked the equation and the units don't really work out.

Assuming:
r = spring rate (lb/in)
w = width of leaves (in)
n = number of leaves (dimensionless)
t = thickness of leaves (in)
L = length of main leaf (in)
SF = stiffness factor (dimensionless)

You get:
r = (w.n/12) * (t.1x10^3/L^3) * SF
= (in) * (in/in^3)
= 1/in

Is there a material stiffness value that is supposed to go in or something (to introduce lb into the units??)

Anyway, I measured my leaf packs and this is what I have:

Front (right and left)
6.5mm x 2 (main leaves)
4.5mm x 6

Rear (right and left)
7mm x 7

What are your thoughts? I'm looking to remove maybe one more leaf from the rear and two from the front, cut them down for even stepping, chamfer the ends and have them reset and tempered. Obviously I'll do some calcs to check it all (which I was hoping to do with the equation you provided)

[isuzurover]

Sorry - you are right - should have been:

r = (w.n/12) * (t.1x10^3/L)^3 * SF

[isuzurover]

Actually, forget that equation, it is oversimplified. I found the proper equation - which I used to design my springs.

it is:

r = 8.E.n.w.t^3 / 3.L^3 * SF

E = young's modulus. Which for steel is:
3.05x10^7 lb.in^-2 or 2.1x10^11 N.m^-2

the equation above is dimensionally correct.


For anyone who is intimidated by the equations, forget about them. You can either design them by trial and error or ask me.

EDIT - for anyone interested, if you substitute in the numerical value for E (lb/in2), you can rearrange the equation to become:
r = 0.25.w.n/3 * 1x10^9.t^3/L^3 - which can be further rearranged into the first equation.

[sclarke]

OK... that makes sence................

:eek:

[isuzurover]

OK... that makes sence................

:eek:

Did you read this bit? ;)



For anyone who is intimidated by the equations, forget about them. You can either design them by trial and error or ask me.

Come on clarkie - you know you want to build a leafer that is more capable than all the coillers offroad, rather than just put a 110 chassis uynder it ;)

What springs do you have fitted at the moment?

[stirlsilver]

Ok,
Did the calcs. By using an SF value of 1.1 (to be conservative) the current configuration of my car is 300lb/in in the rear and 300lb/in in the front... Juding by what you have said before, I should be aiming for 200lb/in in the front! Or maybe less? since i've got the alloy v8.

In anycase, it looks like the rear is pretty right... if I were to remove another leaf from the rear it will drop down to 250lb/in... then again...alloy tray and all that it might work... I'll have to try and see if I can source some shorter U bolts... or put some shims between the leaves.

For the front it seems like I'll have to remove 4!!! of the 4.5mm leaves to get it down to 200lb/in.

So the font packs would have:
6.5mm x 2
4.5mm x 2

that's a very thin front pack!
What are your thoughts ben??

[sclarke]

Did you read this bit? ;)



Come on clarkie - you know you want to build a leafer that is more capable than all the coillers offroad, rather than just put a 110 chassis uynder it ;)

What springs do you have fitted at the moment?

Need to Ask DaveS3, but i think he said Wagon springs with a leaf or 2 removed... and i know its got Mil hangers..
I will have to look at them to see and count the leaves

[isuzurover]

What springs do you have fitted at the moment?

Did you use the leaf thicknesses from here?
https://www.aulro.com/afvb/images/imported/2015/01/984.jpg

I happen to have my Stage 1 supplement at work here, and it says ths stage 1 should have the standard 109" 11 leaf fronts, and the 8+2 leaf station wagon rears - HOWEVER - most Stage 1's I have seen have had the Heavy Duty rears (8x7.1mm leaves).

So if you have standard rears, you should have a rate of either 270lb/in or 368lb/in. IME the LR specs seem pretty good, so what I usually do is use the SF as a fitting factor to match the calculated rate to the one in the manual. For 8/9 leaf rears I get an SF of 1.13.

A rate of about 270lb/in in the rear is a good compromise between comfort/articulation and load carrying capacity. If you don't ever intend to carry a heavy load in the rear you could go a bit lighter, but not a huge amount. If you have the 8-leaf springs though, pulling 2 out brings you down around 270.

If you have 11-leaf fronts, removing 2 leaves brings you down around 220lb/in (from memory), which works well, but for a V8 you could probably pull out 3.




For the front it seems like I'll have to remove 4!!! of the 4.5mm leaves to get it down to 200lb/in.

So the font packs would have:
6.5mm x 2
4.5mm x 2

that's a very thin front pack!
What are your thoughts ben??

Do you have std or aftermarket springs? If std - This is a good reason to use the Manuell values, not measured ones, as they are more accurate!!! There weren't any leaves of those thicknesses in the stock spring packs. The main leak should be 5.15mm and the others should be 4.36mm (or do you have aftermarket springs?)

If you have std springs, I get the following (k = r = spring rate) value at the bottom is the sum of both leaf thicknesses:
Original:
k E n w t l SF
38.5 3.05E+07 1 2.5 0.203 36.25 1.08
234.5 3.05E+07 10 2.5 0.172 36.25 1.08
273.1

3 leaves removed:
38.6 3.05E+07 1 2.5 0.203 36.25 1.08
164.2 3.05E+07 7 2.5 0.172 36.25 1.08
202.8

If you indeed have 6.5 and 4.5 mm leaves - then you are right, 2 leaves of each would give:
k E n w t l SF
154.5 3.05E+07 2 2.5 0.255905512 36.25 1.08
51.3 3.05E+07 2 2.5 0.177165354 36.25 1.08
205.9

[stirlsilver]

I measured the leaf thicknesses off the packs on the car. Couldn't use verneer calipers so the best accuracy I could get to was 0.5mm (I appreciate that the thickness has a large impact (^3)) so you would want to get those values as accurately as possible.

The leaves are definitely not orignial as I bought them new about one and a half years ago. So as a result I don't have the luxury you did of knowing the specifications of the packs.

The actual results I got was 315lb/in on the front and 295lb/in for the rear (I rounded). At the end of the day this is just an approximation, and by using a SF of 1.1 (lowest) it should understate the spring rates.

When I purchased the packs they (before I pulled any out) they came with:
Rear
7mm x 9

Front
6.5mm x 3
4.5mm x 6

[isuzurover]

I measured the leaf thicknesses off the packs on the car. Couldn't use verneer calipers so the best accuracy I could get to was 0.5mm (I appreciate that the thickness has a large impact (^3)) so you would want to get those values as accurately as possible.

The leaves are definitely not orignial as I bought them new about one and a half years ago. So as a result I don't have the luxury you did of knowing the specifications of the packs.

The actual results I got was 315lb/in on the front and 295lb/in for the rear (I rounded). At the end of the day this is just an approximation, and by using a SF of 1.1 (lowest) it should understate the spring rates.

When I purchased the packs they (before I pulled any out) they came with:
Rear
7mm x 9

Front
6.5mm x 3
4.5mm x 6

Fair enough. So your rears may be the 7.1 mm extra heavy duty - but 0.1 mm doesn't make too much difference. I would go with 5-6 leaves.

You can double check the measurements with verniers around the centre bolt hole when you pull the packs apart.

If those rear measurements are right, then 4 leaves should do the job, or 5 if you want to make sure, or have a dual battery/winch.

EDIT - when doing the calcs, the best SF values I found are 1.08 front and 1.13 Rear.

[Ruski73]

I've just put in a 16 gallon tank to replace the leaky 10 gal and noted among other issues that the spring hanger to mount the front of the rear spring set is cosy with the tank and the shackle bolt wont go anywhere till the tank is lowered. Looked like it would have been the case for the 10 gal too or it would have been very close. Question then ... is it just a fact of life that the tank needs to come down to change rear springs on an 88?

If so I suppose I should hold off fitting the second 16 gal on the passengers side until the Minister for War and Finance approves the business case for the RM parabolics ... and at the moment her solution to the rough ride is to go in her Impreza instead.

[Timj]

Hi Ruski,

Yes the tank has to come out to do the rear springs. I have just finished putting new parabolics on the back of mine tonight. Fronts should go in tomorrow. My personal experience with RM parabolics is don't bother, they are not worth the price. Mine had them on when I got it. The receipts show them to be less than 2 years old and the car had not been driven much in that time and they were badly collapsed. Drivers side rear particularly so the car sat at a real lean. The difference between drivers and passengers side was 70mm so I am talking a lot of lean. I also talked to the distributors and the set on mine were not the only ones to have given up very quickly.

I have some standard springs that I was going to put in but I could not get excited about pulling spring packs apart and such like so I got some Britpart parabolics from Sydney. Price was ok so we will see how they go. Sitting them next to the RM they sat at least 50mm higher when upside down on the ground and the drivers side RM was worse by at least 25mm. I haven't tightened everything up yet and the fronts are still the RMs but it now sits nice and level and quite a bit higher.

TimJ.

[101RRS]

Timj - were your parabolics the correct way around - the original springs are stronger on the drivers side and if put in on the passenger side the car would lean to the drivers side.

Are RM parabolics the same??

Garry

[Timj]

Hi Gary,

To the best of my knowledge the parabolics are not sided in the same way the standard ones are. The dramatic difference in height between the old and new ones tends to suggest they have sagged badly as well. I did think about just swapping them over but there was too much difference and I wanted some extra clearance as well having put some big dents in the cross member under the gearbox last time I was 4wding. I believe that the RM parabolics were the best available at one time but that they had some problems with their supplier and quality may have suffered. Not sure if they are back to the best again by now but I didn't want to test it.

Tim.

[Ruski73]

Timj ...

Thanks for the info. I've not settled on a maker yet though I understand RM's would cost a bomb or two. I not only need to soften the ride but also to pick its arse up of the ground. The PO reckons he drove it about without the roof and removing a few leaves didn;t affect the ride height so much but I prefer the roof on and have only known it to sag. Badly.

[boot]

I've got british springs parabolics in my swb (3 leaf rear high and like a load). different vehicle to std springs great to drive on ad off road and igot an extra 100 points on ramp travel.
im just using std shocks at the moment.
mine were over
nz$1000 with new bushes and all new bolts.

friend bought cheap ones for a truck I wont name they rolled up on load off road. buy quality ones!

[JJH]

Hi, could anyone tell me were you can buy quality Para's from in Aus?

[isuzurover]

Hi, could anyone tell me were you can buy quality Para's from in Aus?

Including your location would help.

I believe FWD Motors, at Fairfield Rd Yeerongilly QLD are still the Australian agents for RM parabolics.

[JJH]

Including your location would help.

I believe FWD Motors, at Fairfield Rd Yeerongilly QLD are still the Australian agents for RM parabolics.

Thanks for your reply. I am in Tassie, so It will be with freight regardless. :)

[boot]

there you go that's the twist with std shackles ans std shocks limiting the movement on British spring company parabolics.

[chazza]

Well I decided to modify the standard leafs after seeking Isuzu Rover's help and I can't thank Ben enough for the advice he has given :D

Here is a pic of both of the rear sets reassembled.

https://www.aulro.com/afvb/images/imported/2010/03/1522.jpg (http://s168.photobucket.com/albums/u171/sprawson/?action=view&current=Taperedsprings.jpg)

No before shots; they didn't look too bad but when I stripped them there were wear-steps on all but the bottom one and the upper main leaf, which shows that keeping springs dry and rusty doesn't prevent wear.

The only tools I needed were:
1. My cobber's oxy-set to unbend the clamps.
2. A heavy hammer and an anvil to straighten the ripples in the unbent shackles.
3. A 4" angle grinder with: cutting discs (4 off); a coarse flap wheel and one grinding disc.
4. Marking tools and a hand drill to drill the holes for the keeper-bolts on the clamps.
5. Paint brush.
6. Spanners.
7. Vice.

Materials:
1. A can of dry-lubricant spray 1off
2. 5/16" x 4" UNF high-tensile bolts 8 off
3. About 200ml of Penetrol
4. 1/2" to 5/8" dia. light tube (I used an old folding-chair frame)

Method:
1. Sand the springs to remove loose scale.
2. Carefully grind the wear-steps to remove the obvious ridges.
3. Sand the grinding to make it smooth; ignore any blemishes if they don't feel deep.
4. Mark out and cut the tapered ends 25mm x 12mm with the cutting disc.
5. Sand a radius on the top edge of the taper so it doesn't dig into the spring above when in use. Make the radius about 3mm.
6. Sand any sharp edges to make them safe.
7. Mark-out and drill the holes in the clamps.
8. Penetrol the leaves following the manufacturer's instructions to arrest corrosion.
9. Paint the springs if desired (I didn't).
10. Coat the inter-leaves with lubricant. I used Molybond 122L by ITW Polymers and Fluids (Australia). On the front springs I will use molybond grease to see if there is any noticeable difference.
11.Assemble the springs with a new centre bolt if necessary.
12. Assemble the clamp bolts and crush tubes into the saddles.

I should add that I decided to remove the 3rd spring after Ben told me how much the standard pack could carry.

Hurry up and wait until you can road test them :D (could be years in my case)

Cheers Charlie

[subasurf]

Chazza, you might just have to help me do mine on of these days ;) hahah
Ofcourse, it would be part of the beer economy :D

They look great.

[isuzurover]

Well I decided to modify the standard leafs after seeking Isuzu Rover's help and I can't thank Ben enough for the advice he has given :D

Here is a pic of both of the rear sets reassembled.

https://www.aulro.com/afvb/images/imported/2010/03/1522.jpg (http://s168.photobucket.com/albums/u171/sprawson/?action=view&current=Taperedsprings.jpg)

No before shots; they didn't look too bad but when I stripped them there were wear-steps on all but the bottom one and the upper main leaf, which shows that keeping springs dry and rusty doesn't prevent wear.

The only tools I needed were:
1. My cobber's oxy-set to unbend the clamps.
2. A heavy hammer and an anvil to straighten the ripples in the unbent shackles.
3. A 4" angle grinder with: cutting discs (4 off); a coarse flap wheel and one grinding disc.
4. Marking tools and a hand drill to drill the holes for the keeper-bolts on the clamps.
5. Paint brush.
6. Spanners.
7. Vice.

Materials:
1. A can of dry-lubricant spray 1off
2. 5/16" x 4" UNF high-tensile bolts 8 off
3. About 200ml of Penetrol
4. 1/2" to 5/8" dia. light tube (I used an old folding-chair frame)

Method:
1. Sand the springs to remove loose scale.
2. Carefully grind the wear-steps to remove the obvious ridges.
3. Sand the grinding to make it smooth; ignore any blemishes if they don't feel deep.
4. Mark out and cut the tapered ends 25mm x 12mm with the cutting disc.
5. Sand a radius on the top edge of the taper so it doesn't dig into the spring above when in use. Make the radius about 3mm.
6. Sand any sharp edges to make them safe.
7. Mark-out and drill the holes in the clamps.
8. Penetrol the leaves following the manufacturer's instructions to arrest corrosion.
9. Paint the springs if desired (I didn't).
10. Coat the inter-leaves with lubricant. I used Molybond 122L by ITW Polymers and Fluids (Australia). On the front springs I will use molybond grease to see if there is any noticeable difference.
11.Assemble the springs with a new centre bolt if necessary.
12. Assemble the clamp bolts and crush tubes into the saddles.

I should add that I decided to remove the 3rd spring after Ben told me how much the standard pack could carry.

Hurry up and wait until you can road test them :D (could be years in my case)

Cheers Charlie

Great work! They look better than mine!

Have you reset them yet? They look a bit on the flat side...

[chazza]

Great work! They look better than mine!

Have you reset them yet? They look a bit on the flat side...

No I haven't I thought I would give them a try on the machine first; the ride may still be too harsh and I might want to remove another leaf.

Thanks for your advice Ben,

Cheers Charlie

[isuzurover]

No I haven't I thought I would give them a try on the machine first; the ride may still be too harsh and I might want to remove another leaf.

Thanks for your advice Ben,

Cheers Charlie

One last comment, you may also want to remove the bolts from the outer clamps to get better down-travel.

[ashhhhh]

Is there any downside to these mods?
More likely to break springs?
?

Also, how do you reset the springs?
Is this something a pro needs to do?

[isuzurover]

Is there any downside to these mods?
More likely to break springs?
?

Also, how do you reset the springs?
Is this something a pro needs to do?

There is a very slight chance the life of the springs will be shortened, as they will be flexing more - however no more than any long-travel spring setup.

I installed my springs in 97/98. Since that date I have done heaps of serious 4x4ing and also touring. The rears are fine, however I have broken 2 individual leaves in the front. I think this is more due to the poor quality steel, as they started life as aftermarket springs, made in an unknown location from unknown steel quality. The genuine springs seem to be made of a much better steel than any aftermarket springs.

The springs should be reset on a suitable machine by a spring works, then tempered. You can do this yourself if you have suitable equipment.

[Phil B]

I know this is an old post but I followed the advise and refurbished the front springs on my '78 swb S3 over the weekend
Mine were very rusty and nasty. The result is great and she is now a please to drive. All the chop and noise has gone.
That's for the great advice gents!!!!

[123rover50]

I had reset the front and rear springs on my shorty to sit higher.
The front is still OK but the rears have sagged. Perhaps lost their temper.
I am considering Parabolics. FWD are no longer and it seems no one is importing Rocky Mountain.
Bearmach are available here now so I can buy them but I have read no reports.
Anyone used these that they can report on?

Keith

[S3ute]

Keith,

Hello from Brisbane.

I had been of the understanding that Modern Motors in Dungog were selling Rocky Mountain and Roamerdrive equipment.

I Googled their website just now at:

Parabolic Springs 73588 & 73589 Two Leaf Kit (http://www.modernmotors.com.au/-products/parabolic_springs_73589_73588_two_leaf_kit)

This seems to suggest that they might still be a lead.

Cheers,

Neil

[123rover50]

Thanks Neil. I rang Modern Motors yesterday and the girl I got knew nothing about them. I will try again and talk to someone else.

K

[Homestar]

I had reset the front and rear springs on my shorty to sit higher.
The front is still OK but the rears have sagged. Perhaps lost their temper.
I am considering Parabolics. FWD are no longer and it seems no one is importing Rocky Mountain.
Bearmach are available here now so I can buy them but I have read no reports.
Anyone used these that they can report on?

Keith

I found the same thing with Rocky Mountain - no one is bringing their stuff in at the moment. I even emailed them and they gave me a contact which I rang and emailed and got no reply - ever. I let RM know but they didn't seem to care too much and wouldn't sell me a set directly.

I found some reports on the Bearmach springs - they appear to be made by the same company that makes the Britpart ones. Both seem to have reasonable reviews from what I've found. I bought a full set of front and rears - the rears turned up with Britpart on the packing, the fronts turned up with Bearmach on the packing - have fitted them but not used them, so can't vouch for them at all, but I'm stuck with them due to lack of availability of anything else.

Fimgers crossed - I've seen mixed reviews for all parabolics including RM so will see.

[123rover50]

I found the same thing with Rocky Mountain - no one is bringing their stuff in at the moment. I even emailed them and they gave me a contact which I rang and emailed and got no reply - ever. I let RM know but they didn't seem to care too much and wouldn't sell me a set directly.

I found some reports on the Bearmach springs - they appear to be made by the same company that makes the Britpart ones. Both seem to have reasonable reviews from what I've found. I bought a full set of front and rears - the rears turned up with Britpart on the packing, the fronts turned up with Bearmach on the packing - have fitted them but not used them, so can't vouch for them at all, but I'm stuck with them due to lack of availability of anything else.

Fimgers crossed - I've seen mixed reviews for all parabolics including RM so will see.

I have read the same reviews I think and RM seem to have the edge.
How much lift did you get?
I have 100mm between the axle and bump stop at the rear but would like 200mm at least. My reset standards were 200 but not any more.

Keith

[123rover50]

Keith,

Hello from Brisbane.

I had been of the understanding that Modern Motors in Dungog were selling Rocky Mountain and Roamerdrive equipment.

I Googled their website just now at:

Parabolic Springs 73588 & 73589 Two Leaf Kit (http://www.modernmotors.com.au/-products/parabolic_springs_73589_73588_two_leaf_kit)

This seems to suggest that they might still be a lead.

Cheers,

Neil

No, just rang them again and they said their website is out of date and they dont use it anymore.
Oh well, try Bearmach/Britpart.

Keith

[alan48]

Try

https://www.localsearch.com.au/profile/4wd-industries/nsw/hunter.../maitland/T6Iv

ie 4WD Industries in Maitland NSW as that is where the Dungog Modern Motors fellow went.
Alan

[67hardtop]

Has anyone checked out Heystee parabolic springs?? Hes got lots of nice land rover mod stuff...

Cheers Rod

sorry i dont know how to put links in

[S3ute]

Try

https://www.localsearch.com.au/profile/4wd-industries/nsw/hunter.../maitland/T6Iv

ie 4WD Industries in Maitland NSW as that is where the Dungog Modern Motors fellow went.
Alan





Hello again,

Worth a try, but as suggested I think 4WD Industries and the older Modern Motors are basically the same crowd in a different location.

Back in the day Modern Motors was one of the prime places in the mid Hunter for Series Land Rover parts and service - that seemed to fall apart after Rover was sold off by British Leyland and the network of independents lost their right to sell the cars and/or original parts.

Cheers,

Neil

[Tim_AM]

Try

https://www.localsearch.com.au/profile/4wd-industries/nsw/hunter.../maitland/T6Iv

ie 4WD Industries in Maitland NSW as that is where the Dungog Modern Motors fellow went.
Alan






i just called them- no joy i'm afraid.

[Homestar]

Last week I drove 2 SWB Series land rovers - one after the other. First had standard springs, the second had parabolics. Both had 2 people in them, and not much else. The shorty with the parabolics was soooo much nicer to drive - almost acted like it had coils in it. Can't wait to get mine on the road now they are fitted to it. :)

Big thanks to Mick88 for the drive of part of his collection. :)

[chazza]

Last week I drove 2 SWB Series land rovers - one after the other. First had standard springs, the second had parabolics. Both had 2 people in them, and not much else. The shorty with the parabolics was soooo much nicer to drive - almost acted like it had coils in it. ...

What condition were the standard springs in? Well lubricated and shaped on the ends; or a solid block of dry rust?

Please don't think I am trying to be sarcastic, but for this comparison to be relevant, the condition of the standard springs is important,

Cheers Charlie

[Homestar]

No dramas and a very good point. - the standard springs had all been pulled apart and cleaned - the vehicle has just recently been put back on the road after a rebuild and engine conversion and are in as good a condition as a new set - very little wear at the ends, etc. Apples for apples comparison - good condition, well maintained standard springs versus parabolics - parabolics won hands down - with no load - can't give you a comparison when loaded but as we spend most of the time driving around unloaded there's a noticeable improvement. :)

[cjc_td5]

What is the consensus on running parabolics at one end (front) and conventional leaves on the rear? The rear springs are much longer and easier to get right and multiple leaves are better for load carrying, whereas the front springs are shorter and so leaf spillage (& friction) are much more promounced and harder to get to a supple ride?
C

[Homestar]

What gives you the idea multiple leaves are better at carrying loads? The 101's came standard with parabolics and are rated to a tonne in the back. Early testing showed they were actually good for nearly 1.5 tonnes but the vehicle was designed as a 1 tonner. I've had nearly a tonne in the back of it and it is brilliant with load on them.

Then there's the Merc Ambulances which run just a single parabolic on the arse end and the Transit vans which use parabolic rears too - both newer vehicles, designed to carry loads where engineers have opted to use parabolics.

Given a choice I'd use parabolics on the back any day, I don't think there's any evidence to suggest they aren't up to load carrying duties, quite the opposite. :)

[cjc_td5]

Probably the concept of multiple leaves that take up the load with increasing spring pack deflection, vs relying on increasing spring rate of only one or two leaves. Fair point re your examples though 😊.
Chris.

[JDNSW]

Semi-elliptic springs, such as those used in Series Landrovers need to have their strength tapered from the axle to the ends, as the bending stress on them increases closer to the axle.

The traditional way of of providing this is to use a series of parallel leaves of constant thickness, but varying length. The advantages (A) and disadvantages (D) of this approach are:-

1. The leaves are all made of the same relatively cheap sheet steel. (A)

2. Multiple leaves means less serious if one breaks. (A)

3. Interleaf friction provides built-in damping (A - less dependent on damper) (D - interleaf friction can vary widely from very little with new, oiled, leaves to very high when very rusty or with worn steps inn the leaves, resulting in a rough ride)

So-called parabolic springs are made from a small number (usually 1-4) of leaves, whose thickness is tapered according to the stress along the spring, following a parabolic law. These few leaves are usually designed to touch the adjoining leaf only at a single point at the end of the shorter leaf. They have the advantages and disadvantages :-

1. Each spring design requires a custom roll to make the profiled sheet of steel that is slit to produce the leaves. Unless made in large numbers, this means they are expensive compared to traditional springs (D)

2. Few leaves means a breakage is more serious (D)

3. Little interleaf friction, means almost all damping is from the Damper, and highly predictable (unless the damper breaks or otherwise fails!) (Mainly A, and the reason for their popularity - good ride!)

4. Because the leaf is thicker over most of its length, the surface stress on the parabolic leaf is higher than on a conventional spring. This demands both better quality steel and a better surface finish than the conventional spring, to avoid stress risers that result in fatigue cracking. Perhaps significantly for the roads many of us drive on, stone impacts can damage this necessary surface finish. (D)


Overriding all these advantages and disadvantages may well be the design of the spring. The conventional Landrover springs are designed to operate at rated maximum carrying capacity (and probably more, as Rover learnt early that many owners routinely overload their Landrovers), whereas the parabolic ones may well be designed for the recreational use of the vehicle where, particularly for the swb, little is carried except a driver and a single passenger. Needless to say, this design will be much more comfortable, but may run into problems if you want to use the vehicle one day top fetch a load of pavers!

[chazza]

It is a pity that Isuzurover's photographs of his car with modified standard springs, are no longer visible in his post on page 2 of this thread, because they showed the incredibly good axle articulation that he achieved - possibly as good as parabolic springs.

I mention this for three reasons:
1. The quality of the steel in the Rover springs is very good and Ben did not break any of the original ones.
2. I know of two people who bought parabolics and had two breakages fairly early on. This is probably a result of poor metallurgy, or bad heat treatment. A search on the net finds many anecdotes about breakages.
3. Parabolics are rather expensive and the Rover ones are very cheap.

Cheers Charlie

[mick88]

Our shorty with parabolics on it rides even better when loaded with a 150 or so kg.

Cheers, Mick.

[Homestar]

It is a pity that Isuzurover's photographs of his car with modified standard springs, are no longer visible in his post on page 2 of this thread, because they showed the incredibly good axle articulation that he achieved - possibly as good as parabolic springs.

I mention this for three reasons:
1. The quality of the steel in the Rover springs is very good and Ben did not break any of the original ones.
2. I know of two people who bought parabolics and had two breakages fairly early on. This is probably a result of poor metallurgy, or bad heat treatment. A search on the net finds many anecdotes about breakages.
3. Parabolics are rather expensive and the Rover ones are very cheap.

Cheers Charlie

Agree with most of this and if you're just buying second hand original springs then yes, quite cheap. Finding good ones is becoming harder and buying new standard springs is almost as expensive as buying parabolics.

I suppose it comes down to personal tastes, what you want and what your wallet looks like I suppose. I don't think there's anything wrong with a set of standard springs in good condition, I've just found the ride from parabolics to be better and it suits my project as I'm doing plenty if other stuff to the vehicle to make it suit my needs better. :)

[123rover50]

I have just replaced my multileaf rears on my current project 88".
I had reset each leaf and greased them before fitting. Its a heavy duty pack as well.
It sat fine when I first installed them but as not registered yet I did a few laps around the horse paddock now after afew months it was sitting decidedly low. The front is higher than the back.
So I bought a set of Britpart rears. (all I could get in Brisbane).
The pack I removed, when a straight edge is centred in the two spring eyes, measures 220 mm from the line to the top of the spring pack.
The new parabolics measure 210 mm.
Now fitted it sits up back where I want it. How much they will sag I dont know. I have kept the same shocks on as they are new and have enough travel.
It will be a week or so before I can report on the ride.
The photos show the old pack and the rear with the multileaf on the rhs and the parabolic on the lhs.

Keith

[JDNSW]

Your old set are 'station wagon' springs rather than heavy duty! That is, the main pack is light duty for a comfortable ride, with the very heavy secondary leaves at the bottom to carry heavy loads.

[whitehillbilly64]

I will stick will original, lubed between leaves, on Gilbert.
wont seem so bad if I ride my 77 Honda, Or 1960 Greeves. [tonguewink]

whitehillbilly

[TJWA]

Has anyone checked out Heystee parabolic springs?? Hes got lots of nice land rover mod stuff...

Cheers Rod

sorry i dont know how to put links in

Yes, I have Heystee parabolics on a S3 109" and their power steering as well, both have been excellent the last 3 to 4 years, completely fault free!

The steel of the Heystee parabolics compared to the Britpart ones is more pliable, you get a softer ride and more articulation, I had 2 Britpart parabolic leaves break before I changed to Heystee.

[JDNSW]

Parabolic springs have thicker leaves than conventional springs. From simple geometry, this means that the strain, or stretching, on the upper surface of the leaf is greater than on the conventional leaves for the same spring deflection.

This makes the metallurgy and surface finish of the leaf more critical, as it becomes easier for any imperfection to start a crack due to the formation of a stress concentration. And makes the springs more vulnerable to stone damage. And the fewer number of leaves makes a breakage more likely to disable the vehicle.

[Lewy110]

I was thinking of going Parabolics on mine just after I bought it, but I relly don't find it too bad.

My rear springs are a bit different from standard springs though. Not sure what brand they are.

130433

[granny]

Yes, I have Heystee parabolics on a S3 109" and their power steering as well, both have been excellent the last 3 to 4 years, completely fault free!

The steel of the Heystee parabolics compared to the Britpart ones is more pliable, you get a softer ride and more articulation, I had 2 Britpart parabolic leaves break before I changed to Heystee.

Hi, where abouts did you get the Heystee parabolics from?

[Lewy110]

Here is a better shot of my rear springs

https://www.aulro.com/afvb/images/imported/2017/10/82.jpg

[TJWA]

Hi, where abouts did you get the Heystee parabolics from?

I got them directly from Heystee, I spoke to them a few months ago about getting an extra leaf for the rears as I'm carrying heavy loads these days and wanted the option, they have stopped production for the time being. :-(

[goingbush]

I just ordered a set from GB Springs, UK . (GB only sell direct) for my Lightweight.

Land Rover Parabolic Springs - GB Springs (https://www.gbsprings.co.uk/land-rover/)


Complete set 4 springs , U Bolts & bushes , 585 GBP including shipping = AU $1,111
Hopefully the declared value won't include shipping & it will sneak in under $1000 to avoid customs duty.

[67hardtop]

I just ordered a set from GB Springs, UK . (GB only sell direct) for my Lightweight.

Land Rover Parabolic Springs - GB Springs (https://www.gbsprings.co.uk/land-rover/)


Complete set 4 springs , U Bolts & bushes , 585 GBP including shipping = AU $1,111
Hopefully the declared value won't include shipping & it will sneak in under $1000 to avoid customs duty.Get them to send in two lots. Front and rears. Send on different days as well. Thats how i got my disc conversion sent to me from the Netherlands. Worked great. No duties or GST.

[goingbush]

Get them to send in two lots. Front and rears. Send on different days as well. Thats how i got my disc conversion sent to me from the Netherlands. Worked great. No duties or GST.

Good plan, but too late , its in transit. I did ask them to only declare the item cost & not include shipping, but we will see.