Outer Limits 4x4 Board

Posted: **Tue Aug 19, 2008 7:28 pm**

hey guys i know this has came up alot before but i tryed searching and didnt find anything to help me.

i just got a new 60 it has got rockcrawler springs all round but it flex's like a bath tub.. i am goin to take some leaves out but im not sure wat ones, i was thinking for the front take out the shortest one and the fourth one down
but i dont know about the rear because its got a 160L tank so it will need to be able to take the weight of that but i want it to flex too so i was thinking bout takin the big helper out and the next shortest one
i havnt had anything to do with this before so any help would be great
neither front or rear touches the bump stops when fully flexed
thanks tyson

Posted: **Tue Aug 19, 2008 7:58 pm**

As a rule I pull out the bottom one and then ever second one up until it goes ok but only pull one out at a time and give it a few runs before pulling out the next to give them time to settel down .

when apart put grease between the leaves if they are dry they mat bind and not flex as easy or if you want some people leave them dry and put a thin strip of nylon between the leaves

I'm running rockcrawler springs as well your pic didn't look like my one but the tabs that hold the spring paks together straighten them out to let the leafs seperate don;t do it to the bottom ones but the 4 others

pulling out leaves can lower ur fourby and also in crease the chance of axel wrap and damageing the springs so be carfull how far you go.

let us know how you go

Posted: **Tue Aug 19, 2008 8:13 pm**

You will probably need to get the spring packs reset after to compensate.

Pulling out the shortest spring won't do much. I would try pulling out the 3rd leaf from the top as a start, it won't affect the leaf spacing, and should make a big difference.

If you can crunch a few numbers on a spreadsheet, you can calculate your rates now, and work out what you need to do to get the rate you want. I have posted a thread or 2 somewhere on it.

Posted: **Tue Aug 19, 2008 9:11 pm**

keep in mind the more leaves you remove the softer your ride and more prone youll be to bending leaves, spring wrap and shorter spring life...

That said im only running 3 leaves on my zuk, removed the load leaf from the pack - you can tell the load leaf as its the most arched one, usually near the middle of the pack (undo the retainer bolt and youll see it right away).

Posted: **Tue Aug 19, 2008 9:41 pm**

that bigger bottom leaf is for big loads so it can go .

each leaf from the bottom up transfers the load to the one above so the more even the step up in length of sping the better so that it doesn't load one up more then others

as I said ( as did alien ) be carefull of axel rap it will kill not only the springs but tailshafts and other things if you get alot of grib and give it a bootfull alien have only 3 leafs but remember the size and weight of a zook Vs a big 60'

Posted: **Tue Aug 19, 2008 9:51 pm**

you will probably find that no matter how many leaves you remove you wont be able to flex to the bump stop without W ing the spring, that is bending it past flat. This will kill them quickly! The reason for this is your springs will be to short for the shackles. Ideally IMO the shackle should be flat and the spring flat when your hard on the dump stop. This will maximise up and down travel.

For the front try 75 series main and wrap leaves or complete front springs, as they are ~50mm longer than 60 fronts and combined with your 2'' shackles should give a good result.

Up the rear, you could fit 75 series rears which are longer than 60 rears, just need to relocate the front spring mount. There is a thread with some pics in it I will see if I can find it.

cheers

Posted: **Tue Aug 19, 2008 10:08 pm**

hulsty wrote:you will probably find that no matter how many leaves you remove you wont be able to flex to the bump stop without W ing the spring, that is bending it past flat. This will kill them quickly! The reason for this is your springs will be to short for the shackles. Ideally IMO the shackle should be flat and the spring flat when your hard on the dump stop. This will maximise up and down travel.

Sorry, but this is complete crap! I built my custom springs in 2000, and have been abusing them since then. They are almost inverted at full up travel - hasn't hurt one bit.

Longer springs will flex easier, but will still be inverted at full up travel. Springs should also be "U" shaped not "W" shaped at full up travel. If "W" shaped it means the interleaf spacing isn't ideal.

Ideally, a spring will be flat at ride height for the best travel, but this is usually only possible with SOA designs (e.g. hilux)

Posted: **Tue Aug 19, 2008 10:30 pm**

ISUZUROVER wrote:
hulsty wrote:you will probably find that no matter how many leaves you remove you wont be able to flex to the bump stop without W ing the spring, that is bending it past flat. This will kill them quickly! The reason for this is your springs will be to short for the shackles. Ideally IMO the shackle should be flat and the spring flat when your hard on the dump stop. This will maximise up and down travel.
Sorry, but this is complete crap! I built my custom springs in 2000, and have been abusing them since then. They are almost inverted at full up travel - hasn't hurt one bit.

Longer springs will flex easier, but will still be inverted at full up travel. Springs should also be "U" shaped not "W" shaped at full up travel. If "W" shaped it means the interleaf spacing isn't ideal.

Ideally, a spring will be flat at ride height for the best travel, but this is usually only possible with SOA designs (e.g. hilux)

Hey mate, I think you've read wrong what I said, which bit you believe is wrong?

You've mentioned your springs built in 2000 and they are still going strong which is good!, saying that they dont invert on up travel and go W and U shaped which is good for their life! If they W and U , in a serious way your going to start damaging the spring. IF its a spring like used in a 60 with a decent amount of set camber, repeatedly bending them past flat will wear them out faster than normal.

If a longer spring is correctly matched to the shackles it shouldnt invert at full uptravel and go W/U shaped.

As for SOA designs, I'm yet to understand how it will give a single mm more flex then a SUA design for the same spring packs and tyre clearance. Overall suspension travel should be the same as the spring itself will move the same amount. Would like to know if someone knows? For "flex" reasons SOA seems like a waste to me.

And the ones with a flat spring at ride height, for uptravel do they invert the spring in a W/U fashion for up travel? You would get more travel (down) if the spring didnt invert to reach the bumpstop and a longer spring fitted.

Anyways enough of that, this thread below has some more stuff on it relevant to 60 series cruisers.

http://www.outerlimits4x4.com/ftopic129 ... highlight=

Posted: **Wed Aug 20, 2008 12:22 am**

hulsty wrote: Hey mate, I think you've read wrong what I said, which bit you believe is wrong?

This bit:

hulsty wrote:that is bending it past flat. This will kill them quickly!

my springs have up to 14" of free camber.

isuzurover;709107 wrote: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).

Rear Springs - yes the inner clamps are ridiculously long - I shortened them later

One new rear and one old rear fitted:

Rear compressed (also not all the way):

Posted: **Wed Aug 20, 2008 1:01 am**

my leaves also fully invert their arch... they're almost dead flat on the level, probably only about a 40mm arch in them total... when flexed they're opposing arches, about as much arc as the rears pictured above.

at $90 a pack, who cares if they only last 2 years =)

Posted: **Wed Aug 20, 2008 8:01 am**

ISUZUROVER wrote:
isuzurover;709107 wrote: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).

You've got good quality springs there mate! and what I must be seeing must be the exception. What i've said above is what i've been lead to believe and seen in mates cars, after a few years of hard work doing that kind of things they have begun to sag and lose their tension.

With your setup though, wouldn't a slightly longer spring be more beneficial? but I guess with all things $$$ is what gets in the way.

My front springs are ~20mm to long, and even on full compression they are are not flat but for free springs i'm not to worried. Much better than $$$ on customs.

Posted: **Wed Aug 20, 2008 9:27 am**

Both front and rear springs in my hilux are dead flat at ride height.
Both compress to a U shape for up travel.
Both droop a hell of a long way. I don`t think anybody will arguee this.
Front has been in UNTOUCHED since 2003 or 4
Rear has been in UNTOUCHED since 2002
I have done fastwork, I have done slow work. They have been used and abused for years.
Fronts are starting to show signs of age but still have years left in them.
Nothing wrong with either. Well except for a trailer miss hap o Friday but thats another story

Wth the 60 series, first thing I would try would be unbolt the shocks and then flex it up, see what it does.Then open all the clamps on the spring packs and try it agian. See whats binding and how much extra flex you get by just doing these very easy things.
But becarefull with the rear as you`ll very easily get axle wrap with open clamps.

Posted: **Wed Aug 20, 2008 11:55 am**

Guts wrote:Both front and rear springs in my hilux are dead flat at ride height.
Both compress to a U shape for up travel.
Both droop a hell of a long way. I don`t think anybody will arguee this.
Front has been in UNTOUCHED since 2003 or 4
Rear has been in UNTOUCHED since 2002
I have done fastwork, I have done slow work. They have been used and abused for years.
Fronts are starting to show signs of age but still have years left in them.
Nothing wrong with either. Well except for a trailer miss hap o Friday but thats another story

Exactly - a spring that is flat at static loaded camber (ride height) will give you the best travel (comparing springs of the same rate). However this is usually only possible with SOA designs - which is why I mentionmed SOA.

of course SOA setups are likely to have more axle wrap... so you take the good with the bad.

Posted: **Wed Aug 20, 2008 11:56 am**

ok thanks guys. yeah i have takin the front shockes off and flexed it up and it dose flex a little better cause the shocks are to short im putting longer ones in, and i had unbolted the sway bar and it didnt make and difference. and in the rear i flexed it up and marked it on the shock then i unbolted the skock and it extends another 50mm so i think the rear shocks should be good.
do i need to worry about having the big tank in the rear??

Posted: **Wed Aug 20, 2008 12:13 pm**

60_series_united wrote: do i need to worry about having the big tank in the rear??

How big is the tank?

I assume it is properly designed so there is no chance of the axle coming anywhere near it - even riding on the bump stops?

The weight of fuel will probably be less than the weight of water/recovery/camping gear.

If you mod the springs and they are too soft you can always put a leaf back in.

Posted: **Wed Aug 20, 2008 12:20 pm**

ISUZUROVER wrote:
60_series_united wrote: do i need to worry about having the big tank in the rear??
How big is the tank?

I assume it is properly designed so there is no chance of the axle coming anywhere near it - even riding on the bump stops?

The weight of fuel will probably be less than the weight of water/recovery/camping gear.

If you mod the springs and they are too soft you can always put a leaf back in.

its 160L. no the axel dosent go anywhere near the tank.owell i guess its just trial and error

Posted: **Wed Aug 20, 2008 1:23 pm**

60_series_united wrote:
ISUZUROVER wrote:
60_series_united wrote: do i need to worry about having the big tank in the rear??
How big is the tank?

I assume it is properly designed so there is no chance of the axle coming anywhere near it - even riding on the bump stops?

The weight of fuel will probably be less than the weight of water/recovery/camping gear.

If you mod the springs and they are too soft you can always put a leaf back in.
its 160L. no the axel dosent go anywhere near the tank.owell i guess its just trial and error

It isn't trial and error if you can use a spreadsheet.

As I posted on another forum:

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.

r = spring rate (N/m), kg.m or lb/in depending on the units you use
n = number of leaves
w = width of leaves
t = thickness of each (individual) leaf
l = length of MAIN LEAF (eye-eye with the spring 100% flat)

Posted: **Wed Aug 20, 2008 2:41 pm**

flex is over rated

Posted: **Wed Aug 20, 2008 9:33 pm**

It isn't trial and error if you can use a spreadsheet.

As I posted on another forum:

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.

r = spring rate (N/m), kg.m or lb/in depending on the units you use
n = number of leaves
w = width of leaves
t = thickness of each (individual) leaf
l = length of MAIN LEAF (eye-eye with the spring 100% flat)[/quote]

mate i got no idea wat equation means can u make it a bit more simple for me[/quote]

Posted: **Wed Aug 20, 2008 9:51 pm**

hulsty wrote:you will probably find that no matter how many leaves you remove you wont be able to flex to the bump stop without W ing the spring, that is bending it past flat. This will kill them quickly! The reason for this is your springs will be to short for the shackles. Ideally IMO the shackle should be flat and the spring flat when your hard on the dump stop. This will maximise up and down travel.

Hulsty is onto it - I notice the pic at the start of this thread shows extended shackles. Therein lies your first problem. When your springs go flat has the shackle extended fully - I bet not. The springs are not long enough to do that. I've had 3 x 60's and it didn't work on any of them. If you run longer shackles then you should run longer leaf springs to get real flex. 4" lifted and longer leaf springs are readilly available on ebay at less than $1K all round.

http://cgi.ebay.com.au/ws/eBayISAPI.dll ... RK:MESE:IT

If set up right the 60 can be quite a strong and capable machine. Keep up the good work.

Posted: **Thu Aug 21, 2008 1:24 am**

60_series_united wrote: mate i got no idea wat equation means can u make it a bit more simple for me

Sorry mate - it lets you calculate spring rate - how much your springs will flex for a given mass/load.

e.g. my rear springs were originally 405 lb/in - it tokk 405lb to compress a spring 1" - or 810lb to compress the whole rear 1"

I went down to about 270 lb/in, and can still carry over 1 Tonne in the back (and be just off the bump stops).

But that is on a landy - so don't go by those numbers.

Posted: **Thu Aug 21, 2008 8:21 am**

Nat 84 brings the tech

Posted: **Thu Aug 21, 2008 8:52 am**

ISUZUROVER wrote:
60_series_united wrote: mate i got no idea wat equation means can u make it a bit more simple for me
Sorry mate - it lets you calculate spring rate - how much your springs will flex for a given mass/load.

e.g. my rear springs were originally 405 lb/in - it tokk 405lb to compress a spring 1" - or 810lb to compress the whole rear 1"

I went down to about 270 lb/in, and can still carry over 1 Tonne in the back (and be just off the bump stops).

But that is on a landy - so don't go by those numbers.

Is that what you use as SF in your equation? I couldnt find what its meant to be? Spring force?

Posted: **Thu Aug 21, 2008 5:42 pm**

hulsty wrote:
ISUZUROVER wrote:
60_series_united wrote: mate i got no idea wat equation means can u make it a bit more simple for me
Sorry mate - it lets you calculate spring rate - how much your springs will flex for a given mass/load.

e.g. my rear springs were originally 405 lb/in - it tokk 405lb to compress a spring 1" - or 810lb to compress the whole rear 1"

I went down to about 270 lb/in, and can still carry over 1 Tonne in the back (and be just off the bump stops).

But that is on a landy - so don't go by those numbers.
Is that what you use as SF in your equation? I couldnt find what its meant to be? Spring force?

sorry, SF = "stiffness factor". Varies between 1.0 and 1.3, depending if you have square sut or tapered leaves, if the springs are excessively long or short etc, etc.

Btw - not "my" equation. It is from the SAE "Automotive Leaf Spring Design Manual"

Posted: **Thu Aug 21, 2008 9:40 pm**

i was talkin to a bloke today and he said to remove the 3rd one down and that it should be all i would need to take out other than the huge helper in the rear!

Posted: **Fri Aug 22, 2008 2:24 pm**

60_series_united wrote:i was talkin to a bloke today and he said to remove the 3rd one down and that it should be all i would need to take out other than the huge helper in the rear!

Hmm - is there an echo in here?

ISUZUROVER wrote:I would try pulling out the 3rd leaf from the top as a start, it won't affect the leaf spacing, and should make a big difference.

Posted: **Fri Aug 22, 2008 5:02 pm**

I got rid of the 3rd & 5th leaves when it went from a wagon to a ute. The height is close enough to being the same. The only prob was the spring pack has a rubber mounting bracket around it. so the leaves you take out must be replaced with something the same thickness other wise the u-bolts wont tighten around the spring pack. Its hard to tell from the photo but it looks like you have the same set up.

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