[Damo]

Has anyone got one, or run one before? I want to know if a longer slip joint in the front driveshaft is needed.

Where is Moose when you need him?

[Joe]

I had the calmini one in bullant and i had to use a spacer on the tailshaft but i don't remember what size it was
Standed tailshaft too

[Damo]

Joe wrote:

I had the calmini one in bullant and i had to use a spacer on the tailshaft but i don't remember what size it was
Standed tailshaft too

I have my front diff forward as it is, and it will have to go forward a bit further with a SR. I'm just not sure if i'll need a longer slip joint in the shaft. I'll probably just have to put it together and measure.

[BlueSuzy]

ahem boxtube ahem bodgee ahem

You may need one as the diff will move when articulating. Hilux's have this problem all the time.

[Damo]

BlueSuzy wrote:

ahem boxtube ahem bodgee ahem

You may need one as the diff will move when articulating. Hilux's have this problem all the time.

Hilux shaft maybe? I seem to remember them having a decent length slip joint

[Highway-Star]

Damo wrote:

BlueSuzy wrote:

ahem boxtube ahem bodgee ahem

You may need one as the diff will move when articulating. Hilux's have this problem all the time.

Hilux shaft maybe? I seem to remember them having a decent length slip joint

We had to get a custom front shaft for my Father's Hilux made, as the standard one couldn't handle the lame flex it was getting. The Hilux shaft does have a decent amount of spline, but not enough for a trailing front leaves when a bit more than standard flex is attained. I really want to emphasise the fact that it doesn't get allot of travel.

[Damo]

Highway-Star wrote:

I really want to emphasise the fact that it doesn't get allot of travel.

It's a Hilux, that goes without saying

[BlueSuzy]

When im looking for driveshafts, i plan to search the wreckers for the longest spline from many 4wd's.

[Highway-Star]

Damo wrote:

Highway-Star wrote:

I really want to emphasise the fact that it doesn't get allot of travel.

It's a Hilux, that goes without saying

It got bogged on the footpath on new years eve too! Bloody Hiluxes



I could be wrong here, but I have seen an old series Land Rover with trailing front leaves. The car looked like a farm car, so I assumed it was standard . Just wondering if they might have a long spline in the front as well?

[BlueSuzy]

I would of thought pootrols/cruiser/landys because they would have the most movement from stock - longer splines. But the diffs also ark like stock sierra's. Not forward..

[Paul]

mine is running the shackle reversal, has what looks to be around 2.5 inches worth of spacers...


any reason for going with the shackle reversal? i bought my sierra with it fitted and im trying to figure out what benifits it offers before i ditch it and go back to factory shackle position

[ajsr]

you can buy spline by the metre, half metre and 250mm lengths and the recieving boss from all tractor joints and its cheap.
make your own

[Damo]

Paul wrote:

mine is running the shackle reversal, has what looks to be around 2.5 inches worth of spacers...


any reason for going with the shackle reversal? i bought my sierra with it fitted and im trying to figure out what benifits it offers before i ditch it and go back to factory shackle position

Better approach angle, I reckon the front end will track straighter too.

Something different, and I generally choose the hard way to do everything

[Damo]

ajsr wrote:

you can buy spline by the metre, half metre and 250mm lengths and the recieving boss from all tractor joints and its cheap.
make your own

I found some stuff on bareco.com.au (plenty of cool stuff on there) that would work I reckon. Any other places that you know of?

[Fatzook]

Damo wrote:

Better approach angle

Not unless you cut the perches off your diff and rotate them.

To achieve the same castor as you have now, you will need to have fixed hangers that are as long as your shackles are.

The Calamari kit has some massive fangs hanging down to achieve this.

[alien]

theres other problems inherant with SR though... like the nose diving more under braking, and when you try to climb a rock for instance, the leaf straigtens out before it starts to climb, as the tyre gets pushed back into the wheel arch to its limit before starting to climb up - so potentially you could end up with worse or the same approach angle once the spring compresses.

i was going to SR mine and my engineer put forward a compelling enough argument for me not to (ie: he said "don't do it") lol

[Damo]

Fatzook wrote:

Damo wrote:

Better approach angle

Not unless you cut the perches off your diff and rotate them.

To achieve the same castor as you have now, you will need to have fixed hangers that are as long as your shackles are.

The Calamari kit has some massive fangs hanging down to achieve this.

Yep, it's not as simple as just putting the shackle at the back. I don't like the Calmini setup.

Alien, i'll be using flat or close to flat springs, so the behaviour you mentioned should be minimised. I'm glad I didn't ask an engineer, they are the fun police

[alien]

fair enough - other things to worry about would then include steering linkages binding, diff hitting the sump? and reduced spring rate because you'll be running them on an angle... infact, running super soft flat leaves you'll probably find the diff 'self levels' on the leaves making them S shaped from the start due to the angle you'll be running them on.

[Damo]

alien wrote:

fair enough - other things to worry about would then include steering linkages binding, diff hitting the sump? and reduced spring rate because you'll be running them on an angle... infact, running super soft flat leaves you'll probably find the diff 'self levels' on the leaves making them S shaped from the start due to the angle you'll be running them on.

How would the steering linkages bind? If the diff is moving back under compression the tie rod will be moving away from the draglink. In extension the diff is falling away from the chassis so I can't see the steering links binding there either.

I want the springs to be fairly flat but I won't have them super soft.

Keep in mind that even though the diff moves back it's not a huge amount, I have measured it using the spring i'm looking at using and it's only about 30mm.

[alien]

oh yeah =P haha in my head the steering became backwards too.. lol

in my experience if the leaf pack is near on flat, its soft... my lux leaves being wider helps with stiffness and they dont twist as easily, but their extra length kinda voids that. right now my front leaves are just below flat, ie: about 5mm 'sagged'... thats with 2 leaves up front (both full length). if you lift the front's shackle end up to the chassis, and put a shackle on the back the leaves will be on a fair angle, so what i have now as a kinda sad face shape spring, yours will most likely go S shaped with the perch on the diff trying to level out.

something to help with that though would be fabbing the top shackle pin into the chassis rail like this:

[ajsr]

Fatzook wrote:

Damo wrote:

Better approach angle

Not unless you cut the perches off your diff and rotate them.

To achieve the same castor as you have now, you will need to have fixed hangers that are as long as your shackles are.

The Calamari kit has some massive fangs hanging down to achieve this.

X2
It looks like a pretty shit idea for serious wheeling.
It might make it drive better on the road however.

[alien]

apparently SR'd cars do ride smoother on the road as they absorb the bumps better through the diff moving rearward, but they still have the 'nose diving' issue under heavy braking.

something to consider though is that with 'normal' shackles and flat leaves, under compression or extension the diff actually moves backwards as in either situation the spring is shortened.

if you do a SR on flat leaves the diff movment will be reversed, as the leaf gets shorter the diff will be pulled forwards.

given an arched spring however the results would be reversed.

[Damo]

ajsr wrote:

Fatzook wrote:

Damo wrote:

Better approach angle

Not unless you cut the perches off your diff and rotate them.

To achieve the same castor as you have now, you will need to have fixed hangers that are as long as your shackles are.

The Calamari kit has some massive fangs hanging down to achieve this.

X2
It looks like a pretty shit idea for serious wheeling.
It might make it drive better on the road however.

Yeah I think keeping the spring flat-ish would help, that shackle mount that in Alien's pic, that would help too.

[royce]

would like to see some reference to tech of flat springs being softer and the dive properties of shackle reversal suspension

[alien]

i think the reasoning for flat leaves being "softer" is due to the flatness being achieved by running less leaves - so while it wont absorb bumps any better it will articulate easier with less weight.

the SR dive only happens with an arched leaf, as in that situation the diff travels rearwards... with flat leaves and SR the diff will travel FORWARDS reducing dive and increasing traction to a point.

my setup with flat leaves and normal shackle angle results in more dive and a rear-ward movement of the diff.

what would be ideal is to calculate the arch needed in a leaf that the compression of the spring counters the movement of the shackle, resulting in as close to directly up/down movement as possible - thats how the manufacturers generally set them up and for good reason.

[Damo]

royce wrote:

would like to see some reference to tech of flat springs being softer and the dive properties of shackle reversal suspension

In anything I have read spring rate of a leaf spring is a function of length, width and thickness and number of leaves.

As for the dive thing I have no idea.

[alien]

Damo wrote:

In anything I have read spring rate of a leaf spring is a function of length, width and thickness and number of leaves.

thats correct - but in a braking situation the width of the leaf plays less of a part and it comes down to the length, number of and thickness of, as you're not twisitng the leaves like you would when lifting one wheel and dropping the other, but rather compressing both equally.

best way to simulate this is with 2 plastic rulers... bend them along the long edge and one slides over the other and they arch pretty well. take 1 ruler out and do it again - it travels just as far but with less effort.

Now, twist the ruler... add the second ruler and twist again... its way stiffer and doesnt move as much because the ends are fixed by the hangers (or your hands).

Simple? lol

[Damo]

alien wrote:

i think the reasoning for flat leaves being "softer" is due to the flatness being achieved by running less leaves - so while it wont absorb bumps any better it will articulate easier with less weight.

A leaf spring will be designed to support a certain weight at a certain ride height, called the load rate. Changing the load rate (height it supports at that weight) is totally different to the spring rate (force required to compress the spring a certain amount).

[royce]

Like I thought, another Alien had an idea then busted his brains trying to rationalise it, isnt it time you go bake a cake?

[Damo]

alien wrote:

Damo wrote:

In anything I have read spring rate of a leaf spring is a function of length, width and thickness and number of leaves.

thats correct - but in a braking situation the width of the leaf plays less of a part and it comes down to the length, number of and thickness of, as you're not twisitng the leaves like you would when lifting one wheel and dropping the other, but rather compressing both equally.

best way to simulate this is with 2 plastic rulers... bend them along the long edge and one slides over the other and they arch pretty well. take 1 ruler out and do it again - it travels just as far but with less effort.

Now, twist the ruler... add the second ruler and twist again... its way stiffer and doesnt move as much because the ends are fixed by the hangers (or your hands).

Simple? lol

That means that the more wheel travel you have (more travel = more spring twist) the more the higher the spring rate becomes.

It has nothing to do with the spring rate in a braking situation.