[just_cruizin]

found the cause of my lean, driver's side body mount bent down by 20mm.

[2stroker]

Yeah Steve, mate I am not saying I am right, I think that at speed the uneven bump steer could send the vehicle out of cntrol. If it were acceptable practice manufacturers would run more leaves one side to the other to compensate for weight distribution. To me it just seems common sence to have things the same on both sides. I will do some research and give a more informed reply.

[Damo]

2stroker wrote:

There is a difference between different rates and different amount of leaves

You're right, there is a difference between different rates (eg. different spring rates) and different amount of leaves. The spring rate is measured in lb/in or kg/cm, which basically means it will take a certain amount of force to deflect the spring a certain distance. The spring rate of a leaf spring can be changed by changing any or all of the following parameters:

*Number of leaves
*Thickness of leaves
*Width of leaves
*Length of leaves

2stroker wrote:

all decent suzuki springs are marked right and left for the front because they are different rates to start with.

This is the best solution IMO. Which manufacturers do this?

2stroker wrote:

A 2012 Nissan GT-R may run a different rate one side to the other, but the coil spring still has the same amount of coils left to right.

The amount of coils is not necessarily the point, it's the overall properties of the spring that that affects it's rate that is what's important. The GTR coil springs may look identical in height and amount of coils, but the heavier spring could be made with slightly thicker material to make it's rate higher than the other spring.

2stroker wrote:

I am no expert but then again neither are any of you, speak to some suspension experts and ask them if it is good practice.

You already stated that some manufacturers use different rate springs left to right, so some of them must think it's good practice. Having said that, most people that I have met that propose to be "experts" (regardless of the field of supposed expertise) wouldn't know their arsehole from a hole in the ground

[JrZook]

Damo wrote:

Oh, and FYI. Going back to my original question...

Damo wrote:

I'm in the process of doing a RUF conversion and currently have my leaf springs apart for a service. The driver side spring has 20mm more camber (arch) than the passenger side. Will that be enough?

Now that i've done the conversion and have the springs in place I can tell you without a doubt that, no, 20mm is not enough

Well like I told you, the lean is probs more so dependant on the rear end. Reset your DS rear as well and add a leaf to it.

[Damo]

JrZook wrote:

Well like I told you, the lean is probs more so dependant on the rear end. Reset your DS rear as well and add a leaf to it.

Have you got an extra leaf front & rear?

I put an extra leaf in the front and it's almost there. I think with another leaf in the rear it will be spot on.

[2stroker]

Damo, I don't think you understand what I am saying;

Forget about coil sprung street cars, we are talking about leaf sprung 4x4's and that being said no manufacturer runs more leaves left to right, nor do they run wider leaves left to right, nor do they run thicker leaves left to right nor do they run longer leaves left to right.

They may need different rates left to right due to weight distribution and engine torque effect placing more down ward pressure on the drivers side every time you drive the car.

HOWEVER they achieve this by differering the recurve rate i.e. one spring pack is set with more curve than the other. I have bought King, EFS, OME and all these are marked driver side and passenger side and the driver side is always set higher.

[Damo]

OK I get what you're saying now.

My understanding is that we are talking about 2 different things, spring rate and preload. If you give the spring more height by giving it more arch (camber), that's not changing the properties of the spring (eg, width, thickness, length etc), so it's rate is not going to change.

Will it sit evenly when the vehicle is static? Yes. But I think that a spring with a higher rate will be more able to cope with the extra weight on that side.

FYI, today I have just put an extra leaf in the front and rear packs on the driver's side of my zook so I will be able to do some testing of that setup. Preliminary results on road are encouraging with noticeably less lean, and I have also noticed the ride is more firm.

[2stroker]

My understanding is that we are talking about 2 different things, spring rate and preload. If you give the spring more height by giving it more arch (camber), that's not changing the properties of the spring (eg, width, thickness, length etc), so it's rate is not going to change.

Exactly, you have just backed up my aruement, this is what I am getting at, the manufacturer overcomes the problem by adding recurve (extra arch) in the spring. They do not add an extra leaf because it will change the spring rate from one side to the other which may adversly affect bump steer and other characteristics of the car.

I will guarantee that if you run this past the engineers at Qld transport they will say it should not be done.

[Gwagensteve]

I'm fully aware of both arguments here.

2 Stroker, what I don't think you are taking into account is that it's not really ride height that's the problem, its force imparted on the leaf.

The RHF of a sierra is about 30% heavier than the LHF with a driver in the car. That's a lot.

Yes, it is possible to recamber a pack to hold a static height that's level, and that looks great. However, if the RHF and LHF encounter the same bump, the RHF spring will deflect more because it has the same rate as the LHF but there is more force acting on it - the end result is the that the suspension is "softer" on that side of the car. Not when you bounce up and down on it, but when the car encounters a bump.

Correcting ride height with camber only corrects ride height. It doesn't correct behaviour and will, in fact, lead to more bump steer.

If the RHF is corrected with added spring rate, then when the left and right sides of the car encounter the same bump, the suspension will deflect the same amount on each side.

To test your argument, apply it to the rear of a car that the owner wan't to put a large load in. By your theory, there wouldn't really be any need to add rate, you could just take the stock leaf and camber it more until the car sat at the desired height with the heavy load on board - and that will work, static. Roll down the road though and hit a bump, and the light spring will blow through to the bumpstops.

That's the theory.

The reality is that a car with an added rate on the driver's side feels sprung evenly right to left when you are driving it. This is the case with both cars I have done this with. In both cases these are cars with perfectly even rear weight distribution ( no spare, centred tank) and rear spring rate, but wicked sierra lean on the RHF. One was due to RUF, the other was running stock OME front springs.

Steve.

[Gwagensteve]

Oh, and I am convinced that 60 series turbo diesel cruisers used a torque reaction spring on the passenger's side front from the factory.

Steve.

[christover1]

Is it possible that Suzuki had the LHD market in mind when designing the Zook.
In the USA theres a driveron the left, which may compensate for the right hand weights of battery, spare tyre etc?

[Gwagensteve]

I'd say yes, except that the sierra was primarily designed as a 550cc agricultural car for Japanese domestic use. - the "rest of the world" market was never really a focus early on.

I do agree though, it looks like it was designed for LHD.

I reckon that was a by product of the car being a copy of the WWII jeep, scaled down for Kei rules. Battery location, diff drop, transfer design etc is all basically a copy of the flat fender.

Japanese manufacturers were kings of emulation and were (are?) generally quite slow to change a design if it didn't require redesign.

Steve.

[ajsr]

Gwagensteve wrote:

The RHF of a sierra is about 30% heavier than the LHF with a driver in the car. That's a lot.

Yes, it is possible to recamber a pack to hold a static height that's level, and that looks great. However, if the RHF and LHF encounter the same bump, the RHF spring will deflect more because it has the same rate as the LHF but there is more force acting on it - the end result is the that the suspension is "softer" on that side of the car. Not when you bounce up and down on it, but when the car encounters a bump.

Correcting ride height with camber only corrects ride height. It doesn't correct behaviour and will, in fact, lead to more bump steer.

If the RHF is corrected with added spring rate, then when the left and right sides of the car encounter the same bump, the suspension will deflect the same amount on each side.

To test your argument, apply it to the rear of a car that the owner wan't to put a large load in. By your theory, there wouldn't really be any need to add rate, you could just take the stock leaf and camber it more until the car sat at the desired height with the heavy load on board - and that will work, static. Roll down the road though and hit a bump, and the light spring will blow through to the bumpstops.

Steve.

I 100% agree with the above, the only thing adding a leaf doesnt account for is the natural damping/rebound affect of the extra leaf.

an Ideal way of doing it would be to run 1 heavier main leaf on the heavier side and then run the same leafs through the rest of the pack.
this way the friction forces between leafs should remain the same throughout the suspension cycle. obiously good shocks will help control or balance this as well

steve is correct running the same springs on both sides of an unevenly weighted car would be much more likely to create bumpsteer than running the correct spring weights. The weighted side will just fall though the suspension cycle leaving the other side to trail behind part way through the stroke , changing who knows what in terms front end geometry.

JMO

[Damo]

ajsr wrote:

an Ideal way of doing it would be to run 1 heavier main leaf on the heavier side and then run the same leafs through the rest of the pack.

An excellent suggestion IMO, and that's exactly what I intend doing if/when I get custom mains made up.

[2stroker]

30% heavier on the DSF corner sounds excessive, the wheel base is 2.03 and the drivers bum is situated 800 closer to the rear wheel than the front wheel so the driver actually adds more to the rear corner than the front corner.

A little while back someone on here said they weighed a sierra over 4 corners and spoke of how much heavier the DS front was, I asked what scales were used and where it was done so I could check the data, they didn't post any further. Has someone got some figures please.

ajsr that is a very good compromise and one that I would accept, so apart from my secret springs that I have here where do you get a thicker sierra leaf.

[Gwagensteve]

It was me and and I did post, exactly that, in reply, on November of this year:

Gwagensteve wrote:

2stroker wrote:

Are you serious, are some of you guys running uneven amount of leaves one side to the other.

Steve who did the tech night, what scales did they use and was that 50KG heavier RHF with a driver in the car?

From memory the 50Kg was with driver.

I ran the tech night with SierraJim at his workshop. He has calibrated scales.

Yes, I am totally serious about running more rate on the heavy side. Increasing camber on the RHS eventually leads to sag returning and the process of swapping left to right continues.

More weight=more rate in my book.

It was generally just over 50KG, and the cars were typically around 200KG per corner on the front, so that's 25%., not 30% as I stated. It wasn't anywhere near that significant on the rear but I can't recall the exact figures. It's not just the driver - It's column, steering box, battery - hell, even the driver's side of the motor is heavier with manifold, starter, alternator.

I agree that the inter leaf friction is a factor against an added leaf, but consider that a higher spring rate requires heavier damping and my guess is that these cancel each other out.

Steve.

[just_cruizin]

Interspring friction is a pointless issue to analyse. They all get dust/mud/grass and any sort of other crap we drive through on and over in between them and if someone can quantify a calculation for that is pulling themselves.

More weight requires more spring rate.

Set height means squat over the life of the spring, you might as well set the shackle angle a little steeper if you're doing a RUF.

Either setup the spring with slightly more rate or artificially counter the lean.

[ajsr]

2stroker wrote:

30% heavier on the DSF corner sounds excessive, the wheel base is 2.03 and the drivers bum is situated 800 closer to the rear wheel than the front wheel so the driver actually adds more to the rear corner than the front corner.

A little while back someone on here said they weighed a sierra over 4 corners and spoke of how much heavier the DS front was, I asked what scales were used and where it was done so I could check the data, they didn't post any further. Has someone got some figures please.

ajsr that is a very good compromise and one that I would accept, so apart from my secret springs that I have here where do you get a thicker sierra leaf.

custom main leaf, from somewhere like spicer springs. I was quoted something like $125 ish a couple of years ago when I actually cared if my sierra had a lean

just cruising
with leaf springs I think you would be suprised how much damping affect as extra leaf could have, particularly without seperation/friction pads.

yes trying to measure this would be fun but I'd bet could be fairly noticable
under the right conditions, ie rough, fast road, dry weather etc

[JrZook]

just_cruizin wrote:

More weight requires more spring rate.

Enough said..

[2stroker]

JrZook wrote:

just_cruizin wrote:

More weight requires more spring rate.

I am not disagreeing with that, what I am not agreeing with is that you think rate can only be increased by adding a leaf.

Of course the thickness of the material and the amount of leaves in a pack affect the rate, but that is only part of the equasion, the rate of a spring also has a lot to do with the quality of the steel, and the manufacturing process that turned those raw materials into that spring steel.

It is the reason that there is a difference in performanc between a 2" EFS or OME spring and an inferior ebay spring that may have the same number of leaves.

[Gwagensteve]

I certainly never said that adding a leaf was the only way to add rate. It's one of a number of ways of adding rate, but it's also the easiest to achieve, it doesn't require custom springs to be made, it's reversible, and takes all of 1/2 and hour or so to do.

So you can add rate to counter lean in your driveway very quickly, or you can spend lots of time and money having custom packs made to achieve the same effect except for inter-leaf friction, and then find that the calculation was out and the car now sites high/still sits low on that side.

I might even agree adding a leaf is least desirable way of adding rate, but it's the most convenient, and if you accept that a level car is batter (safer) to drive than a leaning car when it comes to handling, then the accessibility of adding a leaf has to make it worth pursuing before having custom spring packs made.

PS here's an article about leaf spring testing:

http://www.shotpeener.com/library/pdf/1979017.pdf

It's quite old - 1979 - , but interesting. It's a bit off the topic, but tellingly, only one material was assessed -SAE 5160. As the article was done by Ford, it would be safe to assume if different materials were used in different leaf springs, they would have assessed more than one material.

I found it when I was looking for some evidence that different materials were routinely used in leaf spring production. I didn't find anything obvious, and in any case, young's modulus for spring steel seems to be mostly assumed when calculating spring rate as it's only one of a number of variables, and young's modulus is the only useful determinant for the properties of a material used for a spring.

Shot peening and scragging, along with the quality of heat treatment are important, but as far as I can see, they are not variables of rate, only durability.

Slipper pads (for initial rate only), tapered and diamond cuts leaves etc are rate determinants, other than what has been discussed.

I think the difference between spring brands is really in how well designed the leaf is. A leaf with poor materials or heat treatment will obtain the same rate, but it will die from fatigue quickly, but a well designed leaf will have the lowest
rate for a given height, part of the reason I like OME springs - I genuinely do think they are the best designed. They also have the smallest latitude to overloading etc, but you can't have everything - leaf springs are inherently compromised.

Steve.

[JrZook]

Gwagensteve wrote:

I certainly never said that adding a leaf was the only way to add rate. It's one of a number of ways of adding rate, but it's also the easiest to achieve, it doesn't require custom springs to be made, it's reversible, and takes all of 1/2 and hour or so to do.

So you can add rate to counter lean in your driveway very quickly, or you can spend lots of time and money having custom packs made to achieve the same effect except for inter-leaf friction, and then find that the calculation was out and the car now sites high/still sits low on that side.

I might even agree adding a leaf is least desirable way of adding rate, but it's the most convenient, and if you accept that a level car is batter (safer) to drive than a leaning car when it comes to handling, then the accessibility of adding a leaf has to make it worth pursuing before having custom spring packs made.

PS here's an article about leaf spring testing:

http://www.shotpeener.com/library/pdf/1979017.pdf

It's quite old - 1979 - , but interesting. It's a bit off the topic, but tellingly, only one material was assessed -SAE 5160. As the article was done by Ford, it would be safe to assume if different materials were used in different leaf springs, they would have assessed more than one material.

I found it when I was looking for some evidence that different materials were routinely used in leaf spring production. I didn't find anything obvious, and in any case, young's modulus for spring steel seems to be mostly assumed when calculating spring rate as it's only one of a number of variables, and young's modulus is the only useful determinant for the properties of a material used for a spring.

Shot peening and scragging, along with the quality of heat treatment are important, but as far as I can see, they are not variables of rate, only durability.

Slipper pads (for initial rate only), tapered and diamond cuts leaves etc are rate determinants, other than what has been discussed.

I think the difference between spring brands is really in how well designed the leaf is. A leaf with poor materials or heat treatment will obtain the same rate, but it will die from fatigue quickly, but a well designed leaf will have the lowest
rate for a given height, part of the reason I like OME springs - I genuinely do think they are the best designed. They also have the smallest latitude to overloading etc, but you can't have everything - leaf springs are inherently compromised.

Steve.

Major difference between OME and the rest is that OME are one of the very few that still use 6mm steel, not 6.5 or 7 like other manufacturers. Stock Suzuki leaves are also 6mm and seem to be parabolic.

[Daves4wd]

Ok I just got into this debat let's say if you get a newer spring that is lifted and run that at the bottom of the spring pack on the drivers side would that help it at all?? I'm contemplating in doing a ruf with the standard rear springs as I've been told that it will still lift it 2 inchs and I'm thinking of running my 2 inch lifed bottom spring on the bottom of my standard spring for the drivers side if this won't work I might mesure the sag and make it buy putting polyurethane blocks under the spring to lift it up

[Damo]

Daves4wd wrote:

Ok I just got into this debat let's say if you get a newer spring that is lifted and run that at the bottom of the spring pack on the drivers side would that help it at all?? I'm contemplating in doing a ruf with the standard rear springs as I've been told that it will still lift it 2 inchs and I'm thinking of running my 2 inch lifed bottom spring on the bottom of my standard spring for the drivers side if this won't work I might mesure the sag and make it buy putting polyurethane blocks under the spring to lift it up

You have read the thread, haven't you?

[Gwagensteve]

Daves4wd wrote:

I might mesure the sag and make it buy putting polyurethane blocks under the spring to lift it up

Other than perhaps not having read all of the thread, where most of the discussion is about doing exactly what you have suggested, have you considered that adding a polyurethane block (please, steel only) won't "lift the spring up" - it will lower the car.

Is this what you were considering?



You'd need to add the block to the passenger side to lower it to match the driver's side. (not that that is safe)


Were you thinking of "lift blocks?" Like this:




These only work on SPOA suspension, and are considered universally as unsafe for use in the front. Even US magazines that used to feature junk like this all the time:



Stopped featuring cars with front lift blocks in the late 80's because of how unsafe they are.

Steve.

[Daves4wd]

I haven't read the whole thread I've a fair bit but I'm thinking putting the block under the pack I'm not a fan of steel on steel or in other cases metel on direct metal Itll wear it down slowly and cause damage to the springs that's why I was thinking poly blocks but you could do a minimal body lift on one side but even that's pretty stupied but I can't read the whole thread half way through I was feeling sleepy hahaha

[Gwagensteve]

I'll try again.

Is this what your "block under the pack" looks like?



Because that's the only place you could put a block that would change the height of the body of the car with SPUA suspension.... And it would lower the body, not raise it.

If you are planning a block somewhere else, can you find photo of where it will go and post it on here so we can all understand what you mean, because it has me puzzled as to where it could go.

From the factory, every leaf spring car I've ever seen has the Steel spring in contact with the Steel axe pad. It doesn't wear because unless the U bolts come loose, the spring can't move relative to the pad.

If you add a poly block, the U bolts are guaranteed to come loose because the block will squish and end up elliptical. That's why you will never find a lift block made of anyhting except metal.

Yes, a body lift on one side is pretty stupid.

Go and have a nap so you are not sleepy and then read the whole thread.

Sorry for being a bit rude but there's some really interesting stuff in this thread, but it is pretty technical. It seems like you're not 100% up to speed with what's being discussed here. It might be best to add you question to the thread you've already started on RUF ride height.

Steve.

[Daves4wd]

Ok I've read the whole thing and I'm understanding what everyone is trying to say the dsf has a heavier constant load then the psf if you put a load leaf as the rear it could help but eventfully sag over time but if you a really serous about the lean is it worth swapping side from time to time to evenly wear the springs yes it may take a hour or two everytime you do it but it could counter act the wear making it less prone to the unstoppable lean. Sorry about the lift block thing I can't find a pic but what im trying to say is run it in between the the the holding plate so opposite to where it is in the pic you reposted. If it makes sence if not I'll keep googling and see what I can find

[sideways]

Speaking of lift blocks, I serviced the local fire truck a while ago (a late model 4x4 Isuzu).

I couldn't help but noticing on the back diff (SPOA) there were half a dozen bits of flat bar stuffed in there, they spaced the diff away from the spring by about 250mm.

It looked like it was done at the factory.

[Red89]

Daves4wd wrote:

Ok I've read the whole thing and I'm understanding what everyone is trying to say the dsf has a heavier constant load then the psf if you put a load leaf as the rear it could help but eventfully sag over time but if you a really serous about the lean is it worth swapping side from time to time to evenly wear the springs yes it may take a hour or two everytime you do it but it could counter act the wear making it less prone to the unstoppable lean. Sorry about the lift block thing I can't find a pic but what im trying to say is run it in between the the the holding plate so opposite to where it is in the pic you reposted. If it makes sence if not I'll keep googling and see what I can find

The reason you cant find anything is because the only thing it will do is lower the u bolt plate, it wont change the vehicles hieght at all.