Question for you guys.... I am thinking about using 1/4 ellipticals as the lower link on a triangulated 4-bar rearend. I know it has been done on front-end (see attached), but what about on rears? Comments, ideas or suggestions?
I used quarter ellipticals on my Rdst Pu' although I used a straight 4 bar with a panhard bar. Trianglulated rear would work as well.
It came from the factory on a 1926 buick sedan. I am not sure of the 4 link part but it had controll bars on it.
[img=http://img518.imageshack.us/img518/6148/14leaf0169dx.th.jpg] Here is my RPU ,rides nice with half a 57 Chebby spring.
I ran 1/4s on my rear end but I have them mounted at an angle from the frame to set the axle. I have no other links or bars in the mix.
Forgot to add... a stock car style jacking bolt some place above the sping might be useful in adjusting ride height, too. Gary
Ooops. I have to cleanup my last post there. I am running split radius rods that you can see in the photo, so I am running more than the spring, wich my last post sort of implied. By pitching the springs on an angle, I was able to loose the panhard bar that I had no room for. It was an experiment that so far is working really good. (almost 4000 miles so far). One thing I had problems with was weight. My model A has no weight in the back and it rode very stiff. I started adding weight to the frame and now with 100lbs of lead bolted to the read of the frame, she rides like a dream. Or at least as dreamy as 1920's technology will allow.
I have that on my rpu but it hasn't got on the road yet. My 1/4 elips are the lower links with the triangulated top links, no panhard. I am a little concerned about wheel hop though. I have a 24 chevy frame with 1/4 eliptics on all 4 corners. When I first had the idea, maybe 5 years ago, I asked about it on here and met a lot of opposition to the idea. I am sure it will work.
I'm no expert, but when the car is put together and on the road and the back end goes up over a bump, won't it change the angle of the rear end? The spring will get longer when compressed. Is it enough of a change to matter?
Also, how to the rear "Z" effect this set-up? I can't seem to figure how the difference in kick-up would effect ride height on a set-up like this.
We used to call it a leaf link. Run your elips under the rear and your links above. If you build it with a center link location and run your links wide in a triangle (like a 3 link) you can probably do away with a panahrd bar.
What happens if you run the leaf on top and triangulate the links on bottom? I would like to mimic the front leafs... Also, does it matter if the "point" of the triangle is on the axle or on the mounting point (if that makes sense)?
The only thing to watch out for when using the leafs as the lower links is how much torque you are putting to the housing. Light car, skinny tires, no problem. Heavy car with big tires will want to wrap the springs up as the lowers are the ones pushing the car forward on acceleration. Same goes for triangulating the lower bars instead of the uppers. Think about pushing something away from you with a bar at an angle...
I've never run them over the top. I guess you could but I've never seen wone set up that way. And yes it makes a difference about the link mount. I've seen Alphas run the way you are talking about but they work better under a load the other way with the single mount to the chassis. You can over come some of that problem by mounting your shocks in front of the axle. But you are correct about the spring wrap.
Just to clarify, because I think I did not ask my question correctly.... This system works best with the links intersecting at the pumpkin and the other end of the links mounted to either side of the chassis rails? I my have muttled it up more with this question.......shit........
A good friend of mine made a bobber truck with a "leaf link" setup. 1/4's on top with triangulated bars underneath. It rode out great and handled some huge ass hole shots.
No you want the point of the triangle facing forward and the wide part of the triangle on the axle. There ya go it works with the springs on top. I've never done it that way so I couldn't tell you it would work well that way.
It wouldn't be the only thing GM had wrong! Ok, ok, ok...now seriously, it works well either way I would think. It all depends on how you build it. It worked very well with the springs on the top. The brackets for the springs wrapped around the axle to form the mounts on the bottom.
In Post #2, I show the spring on top and parallel bars on the bottom on an International I built. I ran a diagonal link on the bottom bars, just like the parallel 4 link Chris Alston set up on my Anglia.
I ain't saying it wouldn't work but with the triangulated links on the bottom, you would have to have some mounts down low and pretty close to the front of the diff to have enough angle on them, looks to me like anyway. I kept my pivot points for the springs and links in the same plane and tried to keep them parallel at ride height so the pinion angle would be fairly stable throughout the suspension travel. langy, are you using shackles where the springs mount to the rear end? What keeps that from wrapping up when you accelerate?
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