[b.c.kid]

Good day all!
Looking for opinions on the two options for my 32's rear suspension before buying. All I know is price difference. The four link is about $100 more because of the panhard bar. Looking to find out about ride quality and ease of installation beteween the two. Thanks to everybody for the help.

 

[302 Z28]

As you are probably already aware of, the triangulated 4 bar eliminates the panhard bar. I cannot notice any differance between the two to tell you the truth. The triangulated complicates exhaust routing if you are considering going over the axle housing.

Vince

 

[willowbilly3]

I like the looks of the triangulated top link. It is much cleaner. I am toying with the idea of using the triangulated top, only reversed with the single point on the frame member. Then using quarter eliptic springs for the bottom links. This should make a super clean and simple look.

 

[BillyShope]

I like the looks of the triangulated top link. It is much cleaner. I am toying with the idea of using the triangulated top, only reversed with the single point on the frame member. Then using quarter eliptic springs for the bottom links. This should make a super clean and simple look.

This post certainly caught my eye! If you're truly using quarter elliptics, this would definitely provide a "clean" setup. Actually, I see no reason for the top link triangulation, as the quarter elliptics will provide the transverse axle location. There's certainly nothing wrong with quarter elliptics, though their use is rare. Last production car was, I believe, the old bugeye Sprite. (Later Sprites went to semi elliptics.) You'd still want to keep the upper links parallel to the leafs, though the leafs would take up some of the binding (during cornering) if they weren't perfectly parallel. The biggest problem, as I see it, would be to get the proper spring rate on the first try. Couldn't use the Sprite springs, so you'll have to rely on a custom set from some spring manufacturer. This is certainly a project worthy of coverage in one of the magazines. Grass Roots Motorsports or even Road and Track come to mind. Good luck and keep us posted.

 

[willowbilly3]

I am not sure what springs to use yet. I will probably experiment with some junkyard ones first, like from an F-100. I think the triangulated top link or apex locator would help keep the side loads off the springs and would be an added safety device in case a spring ever broke. I also plan to still run the "Z"ed frame so I have bump stops for the axle and a place to mount the shocks. I am running a 27 T touring back half on my body so the top mounting point may be inside the tub and with the triagulated link I would only need one slot in the center of the tub. A custom made rear cross member will house the spring mounts and have a large loop in the center for the drive shaft and the 3rd link mount will be on top of the driveshaft loop.
With houdaille shocks it could be ran with no frame behind the suspension mounts and the axle would be totally visible from the rear, but since it will hopefully be a daily driver I want something to catch it if a spring ever fails.

 

[BillyShope]

I screwed up. Check out my post in the "will this work" thread. I intended it for this thread.

Willow, I think you'll get a laugh out of it.

 

[willowbilly3]

I was thinking something along the same lines as things rattle around inside my head. What if you just mounted the springs solid on both ends with no top link. I wouldn't do it to a daily driver but just to mess with peoples minds on a belly dragging paking lot cruiser. And do both ends. You could even fab the frame mounts with bolts to adjust the stops and dial in the ride height.

 

[BillyShope]

What if you just mounted the springs solid on both ends with no top link.

The top link is essential. Otherwise, you might as well have a pivot at the rear of the spring.

 

[willowbilly3]

Think about it. If the spring was bolted solid to a pad on both ends it would hold up the car. Without going into the torsional twist of the axle during hard acceleration or braking, it would have to be a fairly stiff spring with limited travel but it would hold up the car. I'm not saying I would ever build one but it could work, though without an arguement not well.

 

[cboy]

Think about it. If the spring was bolted solid to a pad on both ends it would hold up the car. Without going into the torsional twist of the axle during hard acceleration or braking, it would have to be a fairly stiff spring with limited travel but it would hold up the car. I'm not saying I would ever build one but it could work, though without an arguement not well.

Actually, I think it would have zero travel - and zero up/down movement. If the ends of the leafs can not move then the spring iteself can not move or bend (that is the purpose of shackles, right?) Mounted like this the spring would no longer be a spring but a metal bar.

 

[BillyShope]

Okay, Willow, I see what you're getting at. I was assuming you wanted something other than the primary bending mode. If you want the spring to bend like the letter "S," the upper link is essential. If you want if to simply bend like a normal quarter elliptic, it is not.

Cboy, perhaps that letter "S" business is a good illustration. You can pick up a length of garden hose between your two hands and form an "S" and, with the help of some friends, you can even add some more bends between your hands. That's what all this silliness is about. We're just playing with the idea of forcing that steel to bend in some unexpected ways. As you correctly indicate, when you start doing that, it becomes "stiffer," as springs go, and approaches the "metal bar" to which you refer. The "S" bending mode would have a spring rate double that of a normal quarter elliptic.

 

[willowbilly3]

Actually, I think it would have zero travel - and zero up/down movement. If the ends of the leafs can not move then the spring iteself can not move or bend (that is the purpose of shackles, right?) Mounted like this the spring would no longer be a spring but a metal bar.

So you are saying if I clamped one end of a leaf spring solid it wouldn't deflect any more if I bolted something to the other end? Why would that have any affect on the ability of the spring to still bend? That's like saying if you clamped me to the end of a diving board it wouldn't spring anymore if some force acted against me.

 

[cboy]

So you are saying if I clamped one end of a leaf spring solid it wouldn't deflect any more if I bolted something to the other end? Why would that have any affect on the ability of the spring to still bend? That's like saying if you clamped me to the end of a diving board it wouldn't spring anymore if some force acted against me.

Billyshope probably said it better but my understanding is that if you clamped one end of a leaf spring solid to your frame and then bolted the other end to your dog - the spring would still deflect (assuming your dog can move). However if you bolted one end of a leaf spring to one side of your frame and then bolted the other end to the other side of your frame, you'd have virtually no deflection. Leaf springs are, in effect, bows. And when the bow is deflected the ends of the bow move either closer or further from one another depending on how the bow is pushed or pulled. That is what happens with shackles, The bow (leaf) is deflected, and the ends of the bow are allowed by the shackles to become longer or shorter. If both ends are clamped solid, the bow can not be deflected (other than the sort of sine curve that Billyshope is talking about).

 

[willowbilly3]

We were talking about quarter eliptic springs that only have one end anchored to the frame and the other end connects to the axle. You are correct that if using full leaf springs and both ends are mounted solid they can't deflect.

 

[cboy]

I think I got confused by one of the earlier posts. I thought you meant bolting both ends to the frame with the axle in the middle somewhere. Sorry if I got things sidetracked on that one.

 

[willowbilly3]

Yeah, I went back a read one of my threads and it wasn't real clear by itself what I was talking about.