Quarter Eliptical Suspension

I wanted to get some advice on this rear setup I'm building. Do you think I need a shackle on the leaf spring at the rear bracket? I thought with a suitable Delrin bushing it would work o.k. Do you think it will bind?
Thanks, Jeff.

 

You have created a 4 bar linkage.
The only difference is one of the links is a spring.

Adding a shackle will create all kinds of problems.

 

That was my take on it. I overthink things sometimes. Thanks for your help. Jeff.

 

You might want to use something just a little softer than Delrin. I have used Delrin on salt flat cars for all suspension bushings very successfully as it is quite hard but will not corrode like aluminum. In your application though, you may want just a little more torsional give than the Delrin will allow.

 

Just a note, your web domain is expired as of the 14th of this month

 

As that spring flattens out with load and travel, it will effectively get longer and short, resulting in axle windup and a lot of pinion angle changes.

 

Do you really think he is the first guy
to use this design, or either end ?

Been done 1000s of times, the sky didn't fall.

 

Exactly. We used to call it a leaf link, but we thought that it made it better with a catchy name.

 

This triangulated panhard should control the pinion angle somewhat? Time will tell. Jeff.

 

How does that center yoke behave if you only lift one wheel?

 

Poorly! I guess thats why its only tacked. If the plate was mounted to a Heim joint where it attatches to the housing it would work?

 

now you have too much going on,its going to bind.

 

You have essentially recreated a A/H bugeye sprite rear suspension. Add a Phanard rod, and some cables or loops to limit axle drop and should be good to go.

 

Good advice guys. Thanks for not calling me an idiot.

 

Your upper trailing arms, and your triangulated arm, are swinging through different arcs, creating a bind in bump and droop.

A large spherical bearing in the middle would allow the suspension
to work in roll. But the front pivot needs to be inline with the trailing arms pivot.

 

The center "Y" yoke is not necessary.
As the suspension compresses, the springs will lengthen and roll the pinion down. The yoke shown will just bind this action. You just need either a panhard bar or a watts link to center the rear end.

Many off road trucks use a similar yoke (longer) on the center of the top housing and only the bottom links out where your springs are. The advantage to this is the high angular articulation required.

J

 

Actually, with the leaf springs solid mounted to the axle, just combine all your upper linkage (move the 2 outer links into the "V" position). The outer links are redundant. Previous posts about the current upper linkage binding are correct.

 

I've done quite a few 1/4 elliptical suspensions in the last few years at my shop. Lately they have been with Posie kits using shackles, P&J ladder bars without a panard and have been very successful. I go back to 1984 when I did my first setup on the rear of a deuce roadster. I used a 40 front spring cut in half for the bottom links and I triangulated the top bars so I didn't need a panard. I used P&J urethane bushings in the ends of the springs and the adjustable 1 inch bars. I see this car almost every year at the LARS and it has over 150K on it and the same suspension is still going strong.

 

you dont need a track locator if your using solid mounted leaf springs.

If you had shackles or some other floating mount you would need one but the way it is now the rear end cant move side to side without taking the springs with it.

I would also suggest that you put all the rear end mounting points in double shear.

 

+1.

That center arm is going to have a much shorter arch (and negative impact)...you don't need it.

Additionally...you need to do some testing with the location of your pivots....ideally, you want the forward connection to be at about the same point as the front yoke of your CV driveshaft. As your axle moves up and down, the pinion needs to stay pointed at the rear of the xfer case.

If you try to use a standard ds and your wanting the linkage to keep the angle right....ain't going to happen if you plan to have any significant articulation.

edit: BTW...nice fab skills.....very nice welding...

 

Your v-bar needs to have a slider sleeve at the rear to prevent bind. If engineered properly it should only act as a centering device.

 

I may not be seeing the whole picture here, but it seems to me that the nicely fabricated V-bar serves no useful function. Actually, it will bind things up and test those good-looking welds. I'd suggest that the V-bar be removed and the bushings in the 1/4 elliptic springs be somewhat elastic. Suspension components being critical, they should be in double shear.
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