Topic: Thoughts on leaf spring suspension?

[bluetoy84]

It seems to be the trend these days that everyrone is trying to build super flexy, RTI ramp champ, 63''chevy ,double shackle , buggy leaf , flex machines. I know it looks cool and your friends are probably highly impressed ,BUT....is it really functional for a trail rig?
It seems that everyone is so amazed with flex that they forget what your springs actually do besides just articulate. What ever happened to good 'ol low slung suspenions that actually work?

Of course all this applies to a rig with both axles locked , but about anyone who is serious is locked at both ends.
Anyways, here's my thoughts and observations:

Stop and think for a second about what is actually making for truck move forward. The only thing attaching your axles and tires to your truck is a leaf spring. So for your tire to move your rig forward your leaf spring is pushing directly against the frame . Right? (this seems to be more of an issue with front springs because of weight transfer) So if you had flat springs with no arc , force is being applied directly to the frame in a straight line. On the other hand if you have super soft 5" springs force is being applied to your frame against an arc and this causes the spring to "bow up" in turn losing energy from the tires . Watch someone with 5" All-Pro or marlin springs climb a steep hill. The front tires will try to run out from under the truck. It looks like the front tires run up under the front bumper.This is the main cause for seperating your front driveshaft. I have seen people who could max out their suspension on a ramp and have plenty of splines left, but would pull it apart on a hill when the axle was not even articulating. This is from the springs bowing up letting the axle move forward. You are losing a lot of energy because of this.

Another factor that affects leaf spring performance is shackle angle and length. I'll use my rig as an example. I'm running rears up front (7 leaf pack) with 6" center hole to center hole shackles. On flat ground I have a lot of shackle angle ,their laid back almost against the frame , but when I'm on the gas hard in 4low the springs will wrap up until the shackle is straight and stops them from going any further. Whereas if your running a stock length spring with a short shackle that is almost straight up , if your front axle tries to wrap or move forward it is stopped by the shackle so instead of the spring pushing against the frame it is now pulling also.

And just because you've got 30" of travel and you always keep a tire on the ground , that don't mean that the tire thats dropped 2 feet away from your rig is actually doing anything to move you forward. Traction is greatly affected by contact pressure , and that tire thats dangling away from your rig might be touching the ground , but the one stuffed up in the fenderwell is the one with all the traction.

The most capable leaf spring rigs that I have drove or seen have all been low lift rigs with very mild suspenions. I know super flexy suspensions might be great if you wheel over rockpiles on flat ground , but from my experience these "long travel" front springs suck on anything that is the least bit steep.

Does all this make sense to anyone or am I the only one who sees it this way? I'm about to ditch my rears up front in favor of some stock length 3" springs and a shorter shackle. I had these on my last truck and they performed way better than the rears up front. I'd like to hear some more opinions on this theory , so post up.

[IronClad]

learn to drive.  i wheel a stupid flexy truck and id rather have that suspension over my old 3" lift springs

[bluetoy84 [OP]]

learn to drive.  i wheel a stupid flexy truck and id rather have that suspension over my old 3" lift springs

Good for you. I'm glad you like what you have. If I wanted someone to insult my driving skills I would have posted this on PBB.

I was just wondering if anyone else preffered a low lift stock length front spring instead of all the tall super flexy springs. I've been building and wheeling toyotas for years , but I just built a new rig and I've been disgusted with the rears up front on it. Also I have a buddy with 5" all-pros and they are already bent from axle wrapping so bad. My intention is not to offend anyone with "mad flex"  I just can't seem to get this truck to hook-up like others I have built and this is the conclusion I've come to. I was just wondering if anyone else has noticed the same problems.

[FIREBALL]

You have some good points about some of the issues with long leaf springs. If they aren't built/designed right and the shackle angle isn't setup right you will certainly have problems like axle walking and seperated driveshafts. Poor quality springs, like all poos have a reputation for sagging and "w"ing etc.
While you may lose some contact pressure, a little is better than none at all. Also a tire (tire, wheel, axle, etc. ie. a bunch of weight) 3 feet in the air just moved your center of gravity much higher and decreases stability and increases you're chance of a roll over.
I agree that a ramp champ is probably not going to be the perfect trail rig, but I still think a good trail rig that has good travel will work better and ride better in the long run than a rig that carries a tire over every bolder.
But........that's just me.

[bluetoy84 [OP]]

Well , I ditched the rears up front last night. I went back with some old 3" lift springs (not even sure what brand). I could imediatley tell a huge difference as soon I climbed the first hill with them. Before with the rears up front it felt like the rear end was doing most of the work and my front end felt like it was trying to rare up , now it feels like the front end is pulling the truck forward instead of the rear end pushing. I got on a steep hill and let it roll backwards and dumped the clutch in 2nd gear double low and it just launches forward. With the rears up front if I dumped the clutch while rolling backwards it felt like it was going to flip over backwards. It was seriously unloading the weight off of the front tires.

I believe for the rears up front to work correctly you would need to move your shackle hanger backwards about 1.5" to get a more vertical shackle angle. Another thing I noticed was that when I took the rears off and stood them up in the floor next to my 3" springs they had about 4" more arc in them than the 3" lift spring , but my truck still sits at the same ride height with the 3" springs. Is it possible that the rears had stored energy causing the front of the truck to feel light when climbing a steep incline ? They were compressing about 4" with the weight of truck on them , and I think that when I would start up a hill and the weight would transfer to the rear end the front  springs were unloading the 4" of compression they had stored.

Anyways, I lost about 2" to 3" of articulation and it rides just a little stiffer but the traction that I gained is well worth the trade off to me. My truck performs 10 times better now than it did with the rears up front.

[sof'indetermined]

i ran 3 inch lift springs(superlift) with short shackles on my truck for awhile, i didnt like them much at all, while i think there is such a thing as having too much flex i wouldnt give up my rears up front for anything.(mine does have the shackle hanger moved backwards though to accomadate the 90 pickups longer rear spring thus giving me a better shackle angle then you say you had on yours) maybe you just needed too make some changes to yours to make them more suited to your driving style, i made several changes to mine before i was happy with them. but really in the end it just matters how you like it and if your new springs work better for your style of driving and for the places you wheel then cool.but i still think my rears up front kick a$$

[bluetoy84 [OP]]

I modified my rears up front several times and the best setup I found was 6 leafs plus the little short overload spring from the bottom of an '81 rear pack and added spring clamps to keep the leafs from fanning out. This worked better but it was still axlewrapping and walking out from under the truck. Most of the time they worked great but there was a lot of times that I've had to pull a cable (mostly on steep hills) when I should have been able to drive up it and I believe it was because the front end just wasn't hooking up like it should. I live in the southeast and most of the trails we wheel are muddy limestones and steep ledges that offer almost no traction ,so anything you can do to get more power to the ground helps a lot. Maybe its not an issue out west on dry rocks. There are some guys that wheel with me that have bought 5" all-poos and 5" marlins and they are suffering from the same issues. But, there's a couple other guys running 3" all-poos and they seem to work great. They are not wrapping and walking out from under the truck like the 5". I dunno, I was just wondering if anyone else has noticed the same thing as us.

[toada]

I modified my rears up front several times and the best setup I found was 6 leafs plus the little short overload spring from the bottom of an '81 rear pack and added spring clamps to keep the leafs from fanning out. This worked better but it was still axlewrapping and walking out from under the truck. Most of the time they worked great but there was a lot of times that I've had to pull a cable (mostly on steep hills) when I should have been able to drive up it and I believe it was because the front end just wasn't hooking up like it should. I live in the southeast and most of the trails we wheel are muddy limestones and steep ledges that offer almost no traction ,so anything you can do to get more power to the ground helps a lot. Maybe its not an issue out west on dry rocks. There are some guys that wheel with me that have bought 5" all-poos and 5" marlins and they are suffering from the same issues. But, there's a couple other guys running 3" all-poos and they seem to work great. They are not wrapping and walking out from under the truck like the 5". I dunno, I was just wondering if anyone else has noticed the same thing as us.

dam good points i have rears up front with the front pack mixed in.
kinda flat but on 33" locked front and rear it hooks up.
good post bro.

[Tim]

I have yet to test my set up, but I am already running into problems.  I have a 1980 Toyota reg cab long bed.  I purchased a 5" Marlin lift with the 12" Bilstein 5150 with cooresponding shock tower hoops.  So after moving the front hanger forward 1/2" and putting the front together I have a shackle angle at about 50 degrees give or take, Please tell me if that is a bad thing.  The rear spring hanger is moved forward 6" eye to eye and the rear shackle hanger 2" rearward.  I have a shackle angle of damn near 80 or more degrees.  The truck is right at the factory wheel base but it is extremely stout in the rear by almost 2 inches.  I also ran into a problem with the 12" shocks not having enough downward travel, about 1/2" past full extention of the shock which also has me up in the air, mentally. 

I have come to a conclusion to shorten the rear shackle to make the angle some what better and less tall, then add a little flat bar to the bottom front shock mount making the travel better.

I think the specs I was given to build this beast could be changed a little.  For a four inch lift this set up would be perfect, minus the rear shackle hangers 2" rearward placement, because the wheel base shock travel and shackle angle will work out perfect.  For the 5" lift I would recommend 3/4 inch forward front hanger placement, the 14" shocks with the 12" or short travel shock hoops and move the rear shackle hanger back only one inch.

[DTB]

I have yet to test my set up, but I am already running into problems.  I have a 1980 Toyota reg cab long bed.  I purchased a 5" Marlin lift with the 12" Bilstein 5150 with cooresponding shock tower hoops.  So after moving the front hanger forward 1/2" and putting the front together I have a shackle angle at about 50 degrees give or take, Please tell me if that is a bad thing.  The rear spring hanger is moved forward 6" eye to eye and the rear shackle hanger 2" rearward.  I have a shackle angle of damn near 80 or more degrees.  The truck is right at the factory wheel base but it is extremely stout in the rear by almost 2 inches.  I also ran into a problem with the 12" shocks not having enough downward travel, about 1/2" past full extention of the shock which also has me up in the air, mentally. 

I have come to a conclusion to shorten the rear shackle to make the angle some what better and less tall, then add a little flat bar to the bottom front shock mount making the travel better.

I think the specs I was given to build this beast could be changed a little.  For a four inch lift this set up would be perfect, minus the rear shackle hangers 2" rearward placement, because the wheel base shock travel and shackle angle will work out perfect.  For the 5" lift I would recommend 3/4 inch forward front hanger placement, the 14" shocks with the 12" or short travel shock hoops and move the rear shackle hanger back only one inch.

u know what they say a picture can say a thousand words....sounds like the shocks definitely arent long enough.....but thats easy to fix

[Rockcrawlintoy]

i run rears up front and i have never had issues hookin up when climbing. maybe its the long wheelbase but my rears have always hooked up

Drew

[Tim]

To make up for the problem in the rear I took the shackle, which is 5 1/2" eye-to-eye and made a custom boomerang shackle out of it with a new eye to eye of 3 7/8".  I wish I had some pictures for ya but it dropped my rear end down enough to make it look like a truck and not a hot rod, lol.  Well the front shock lower mount is an easy fix like you say but no hurry.  I am satisfied.

[Hyena]

I run a flexy suspension that most people say doesn't work very good.  it seems to work pretty good to me.  rears up front work great.  the chevies with the double shackle and the main shackle being about 9 inches in length flex more then great.  they are very stable on slopes too.  the only problem with the chevies is they are rock anchors both front and rear mounts.  thats why i am going away from that route.  but i am not going with leafs in the rear again.  it is going to be a four linck with air shoxs.  Ironclad's point about the driver is right.  you could have a well built rig but with the wrong driver in the seat it aint gonne go nowhere.  it is all about choosing the right line and where you set your tires and how much throttle to use.

[854RUN]

Ironclad's point about the driver is right.  you could have a well built rig but with the wrong driver in the seat it aint gonne go nowhere.  it is all about choosing the right line and where you set your tires and how much throttle to use.

Ya I agree its like Nascar, they have the same HP, suspension is set up to the drivers liking. So what makes a winer, THE DRIVER. but at the same time if you put a wining driver in a car that is setup for a wining diver he wont be wining until they get the car dialed in for him. The same setup works diffrant for each person. 

[bluetoy84 [OP]]

I agree with ya'll, as a driver you have to be comfortable with your setup, whatever that might be. 

I think the type of terrain you wheel has a lot to do with it also. The super long travel springs might be the ticket out west. I don't know, I've never been there. Me and the guys I wheel with run some of the toughest trails in the southeast and we have ran about every type of leaf spring setup possible. The rigs with shorter, lower lift springs consistantly performed much better in our area. The trails we run are generally slick rock ledges and creekbeds that offer very little traction and the lower COG rigs hook up much better on the slick rocks. The long travel springs tended to unload and axlewrap very badly, just because a spring has more flex doesn't mean that it's transfering more energy to your rig.


I knew that I would get a lot of negative comments when I started this thread. I was just stating some of the issues with leaf springs that I have had and seen on the trail. It just seems to me that a lot of people get too caught up with trying to get every inch of articulation that they forget that your leaf springs are the only thing transfering forward motion from your tires to your rig.

This seems to be a factor mainly on front springs because of weight transfer.

Think about this: for your rig to move forward, the tires get traction, traction from the tires = forward energy, forward energy is transferred from the tires to the frame via your leaf spring. So your axle is pushing against the spring, the spring is pushing against the frame, your rig moves forward. Simple. Or is it? Think about HOW this force is being applied to the frame.

With a lot of arch in your springs you are pushing against an arch and below the frame, this tends to make the springs "bow up" and makes the front tires run away from the truck. This is the reason you need so much slip on the front driveshaft. I have seen rigs that could max the suspension out on a ramp and the driveshaft would not come apart, but as soon as they started up a steep climb the front driveshaft would seperate because the front axle tried to run out from under the truck. The shackle angle also greatly affects this. With a lazy shackle angle there is much more axlewrap than a more vertical shackle angle.

I'm not saying none of these springs work well, I've just noticed some issues that could be improved. Next time your on the trail with someone running Marlin, All-pro, trail gear, or rears up front, watch how the front springs behave when they are really hammering on it on a steep ledge. Pay close attention to the distance the shocks will extend and how the shackle angle will change as more torque is being put on the springs even when the axle is not articulating. Also watch how badly the leafs will fan out on the shackle end of the front springs just from getting on the gas.

This is hard to explain unless you see it firsthand. Pay attention and you'll notice what I'm referring to.




 

[alwayzbroken]

My front springs have a very lazy shackle angle. I will give a full report on my 5" TG springs after new years.

[88stewy]

The other thing here that we need to remember is that we are using a "vintage style" suspension system to do something that they were never designed / engineered to do:  Rockcrawl!  The leaf spring set up gives many, many years of trouble free working suspension with a "not so bad" ride to the average / all around rig. 

I am NOT a suspension geek but would have to say that the leaf sprung rig is far from "hi tech" when it comes to using them for extreme wheeling.  yeah we can change the spring thickness, amounts of leaves and lengths but your still using an old school suspension system.  Now don't get me wrong, it still works pretty darn well for most all things but I think if you want a rig that is extremely capable you have to set it's suspension up for what it is going to be used for most of the time.

You will NEVER see a good competition rock buggy using leafs, they all use 3 or 4 links.  Why?  Because that is what works BEST in comp rock crawling, plain and simple!  Those buggy's see VERY LITTLE street time so why wouldn't they use the multiple link set up.  Leaf springs would hold them back from there max potential.

We all want (myself included) our trail rigs to perform at there peak best on the trail but the reality is that probably 90% of use our rigs for more then just crawling.  we drive them to School, work, the Grocery store or on a Sunday drive. 

Bottom line, remember what you use your rig for the very most, and build it around that.  To most of us (myself included) leaf springs will work out just fine most of the time.

There is my .02 cents for what its worth......

[alwayzbroken]

In my opinion Toyotas are only good at one thing and that is crawling. I can't keep up with V8 rigs in mud or on steep muddy hill climbs. The 4 cylinder just doesn't have it in it. So that leaves me to crawling which really isn't effected by many of the factors listed above. I have the 5" Trail Gear springs and can say they work great. Who cares if the energy is not being transferred to the frame properly when you are going 1 m.p.h.

[Nothingface5384]

so do you think marlins 4in springs would still have too much arch to transfer energy to the axle properly or do you think they'll perform similar to the 3 inchers?

[denis]

Me and the guys I wheel with run some of the toughest trails in the southeast and we have ran about every type of leaf spring setup possible. The rigs with shorter, lower lift springs consistantly performed much better in our area. The trails we run are generally slick rock ledges and creekbeds that offer very little traction and the lower COG rigs hook up much better on the slick rocks. The long travel springs tended to unload and axlewrap very badly, just because a spring has more flex doesn't mean that it's transfering more energy to your rig.

I think all things equal a soft rig might have more weight transfer than a stiff rig, with the 60/40 weight bias our trucks have this will mean that on a steep incline the weight might be 40/60 for a soft rig and 45/55 for a stiff rig, which might suffice to explain the traction difference ?
Same therory as the buggy axle winches ?

[ZUK]

I agree with ya'll, as a driver you have to be comfortable with your setup, whatever that might be. 

I think the type of terrain you wheel has a lot to do with it also. The super long travel springs might be the ticket out west. I don't know, I've never been there. Me and the guys I wheel with run some of the toughest trails in the southeast and we have ran about every type of leaf spring setup possible. The rigs with shorter, lower lift springs consistantly performed much better in our area. The trails we run are generally slick rock ledges and creekbeds that offer very little traction and the lower COG rigs hook up much better on the slick rocks. The long travel springs tended to unload and axlewrap very badly, just because a spring has more flex doesn't mean that it's transfering more energy to your rig.


I knew that I would get a lot of negative comments when I started this thread. I was just stating some of the issues with leaf springs that I have had and seen on the trail. It just seems to me that a lot of people get too caught up with trying to get every inch of articulation that they forget that your leaf springs are the only thing transfering forward motion from your tires to your rig.

This seems to be a factor mainly on front springs because of weight transfer.

Think about this: for your rig to move forward, the tires get traction, traction from the tires = forward energy, forward energy is transferred from the tires to the frame via your leaf spring. So your axle is pushing against the spring, the spring is pushing against the frame, your rig moves forward. Simple. Or is it? Think about HOW this force is being applied to the frame.

With a lot of arch in your springs you are pushing against an arch and below the frame, this tends to make the springs "bow up" and makes the front tires run away from the truck. This is the reason you need so much slip on the front driveshaft. I have seen rigs that could max the suspension out on a ramp and the driveshaft would not come apart, but as soon as they started up a steep climb the front driveshaft would seperate because the front axle tried to run out from under the truck. The shackle angle also greatly affects this. With a lazy shackle angle there is much more axlewrap than a more vertical shackle angle.

I'm not saying none of these springs work well, I've just noticed some issues that could be improved. Next time your on the trail with someone running Marlin, All-pro, trail gear, or rears up front, watch how the front springs behave when they are really hammering on it on a steep ledge. Pay close attention to the distance the shocks will extend and how the shackle angle will change as more torque is being put on the springs even when the axle is not articulating. Also watch how badly the leafs will fan out on the shackle end of the front springs just from getting on the gas.

This is hard to explain unless you see it firsthand. Pay attention and you'll notice what I'm referring to.

I agree.  I would like to see you try the shackle reversal (shackle to the front).....some of the issues you mentioned go away.

[skid]

compramise.    Softer spring for better ride and more flex.  But, more axle wrap and more unloading on climbs.   Really hard to fit a flat spring on a Toyota.  Want bigger tires, more lift/ more arch on the springs.  Crossover without hacking the frame and oilpan, more lift.

Want to limit droop on climbs, rig up a winch cable.  Regardless of front suspension, this works on linked rigs as well.

My view,   soft springs are more gracefull.    I feel I have way more control over the stiff flat springs.  More control = less broken parts for me.

The search continues for a happy medium.

[bluetoy84 [OP]]

As mentioned before, different terrain requires different setups, and every driver has his own preference. I'm just thought I would share my observations of some problems I've seen with the long travel springs.

Here's an illustration to better explain what I'm referring to.

[skid]

Often wondered if mounting the shackle higher on the frame would make a difference.  In theory forcing the spring to compress a little when the axle drives forward, prosquat?