1/4 elliptical design question.

[baddawgcustoms]

I'm considering using the 1/4 elliptical setup on my frame, and the design I'm considering is using the spring as the lower half of the 4 bar setup without a shackle so no panhard bar is needed. What I don't understand for the life of me is how this setup doesn't get in a bind when one wheel goes up (just say for instance right side is up on a curb and the other is still flat). With no way for the location where the spring attaches to pivot, it just seems like the front of the spring would try to twist. Also, I've read in several places this setup is not recommended with a tube axle because it will not flex like an I-beam axle can. I've received tons of education by reading the forums from my fellow gear heads with much more experience than myself with these cars, and thanks a million for it. I've been planning this build for several years but I just don't want to start buying anything (other than engine trans and rear). Till I have the plans drawn out. The one thing I am taking to heart about the advice I've read, is poor planning leads to poor designed cars, and I want that nipped in the bud before I turn on my welder. I know sometimes things change on the fly, but I want surprises to a minimum. Thanks for the help ahead of time.

 

[EX JUNK]

I have a quarter elliptic set up on my car with a tube axle, shackle mounts, cross steer and a panhard bar. It has been trouble free for close to 15K miles.







Jim

 

[baddawgcustoms]

Jim I've enjoyed reading your posts these last couple of weeks and looking at pics of your beautiful car but the design and engineering behind it tells me you do know a thing or two about building cars. Now that I've thrown the flowers your way, I did get a lot of tech advice from a rock crawling 4x4 nut today that kind of explained a lot to me. He showed me photos of 1/4 elip setups where the spring twists over 30 degrees with no trouble. (Guess that's why they call it "spring steal". I'm looking for the "lakester/modified" look up front and my 4x4 guy said your setup was perfect. Basically he said your setup works with a 4 bar because your springs are shackled and you have the panhard, and it made sense after he explained a little geometry to me. Tell me if you think this is right...

1/4 elliptical WITH shackles MUST run panhard and can use hairpins, radius bars, 4 link...... Ellipticals mounted solid with no shackles do not need panhard bars, but you should never run a 4 bar setup hairpins/radius rods etc), because when the spring flexes it moves out, or in, and the axle can't move forward or back because it's tied to the bars and will stretch the bars and bind. Although most of the lakesters run the setup with radius arms and ellipticals with no shackles, it's not the safest setup. That's why I-beams are recommended because they will flex some where tube axles will not, but the whole design is still not optimal.

Probably tired of reading my long drawn out discourse, but I can only afford to build this once. Long story longer, I want to run the lakester extended front end, but no place out front to mount a panhard setup so no shackles for me. What was recommended to me was using the springs as the bottom of the 4 bar type setup, and doing a triangulated upper bar setup. No panhard needed and the caster stays correct and total fluid movement like a triangulated 4 link rear suspension. Curious to search for anyone who has done it that way. Thanks for your time. It's appreciated.

 

[baddawgcustoms]

I did find this setup, but wonder if it would work the same with the upper bars moved outward, rather than toward the middle. Toward the middle would obstruct the view of my pretty grill!

 

[old round fart]

Looks to me the springs and the upper bars are close to the same length. That's good. Just be sure the springs can't move side to side and you're golden! Have you thought about shocks? John

 

[Hotrod46]

Miller used 1/4 elliptical springs without shackles to locate the tube axles on his Indy cars back in the 30's. He used 2 springs on each side as the upper and lower bars of a 4-bar setup.

Here is the setup on the front of my bucket.


I have almost 14000 miles on this car. Drives good. 75 mph pulling a trailer is no problem. It's also seen some very curvy roads with no issues other than understeer when pushed hard in a turn. That could be related to the limited slip rearend.

No panhard bar, but it does have shackles. Side steering, though. If I did it again, I would pull the axle closer to the frame like ExJunk's so that I could use a standard shock setup. The extended wheelbase does push the center of gravity back. My weight distribution is about 40% front 60% rear.

Mike

 

[baddawgcustoms]

John I'm a truck driver so I have nothing to do all day long but think about this crazy car! I believe that once I determined I WAS building it, my obsession level has maxed out. I love the look of the old original friction shocks like the picture below. I would love to incorporate them into my car, but I'm unsure just how well they would work with a rod that long. I have a tendency to overthink things I'm building but it usually pays off in all the bikes I've built, just takes me twice as long as it could have. Any thoughts on the shocks? What I'm going to try is almost just like ex junks, just using the springs for the bottom bars mounted with no shackles, and the upper bars pretty much just like his in about the same location. I love the look in the picture, I'm just obsessive over geometry being as perfect and safe as possible. My name on here "bad dawg customs" is from my Harley building days. I think my obsession with engineering came with my first ground up bike build before I had a good understanding of rake and trail. (It ended very badly). I enjoy the gizmoness and mechanicalnessness as I call it, more than aesthetics!

 

[Hotrod46]

I should also add that my frontend articulates better than most T-bucket frontends that I have seen. It soaks up angled speed bumps and irregular roads easily.

Mike

 

[EX JUNK]

One of the main reasons that I chose to use a panhard bar was because of the cross steer set up along with the shackles. I wanted to not take a chance of any lateral movement of the axle. As for the set up that you pictured in your third post, I would say that it would work equally well with the rods inward or outward. You are still triangulating with the parallel springs to keep the axle centered. IMHO

Jim

 

[Hotrod46]

The shocks in your picture look like Houdaille shocks. Mostly used on early Fords, but were used on other makes, too. They are hydraulic rotary shocks. Some only dampen on rebound, but the later model damp in both directions.

 

[baddawgcustoms]

Mike that's one beautiful car you have and love the grill. exactly what I have in mind. And I may just steel your shock setup. Looks awesome.

 

[Hotrod46]

Baddawg Thanks. That is a 4 1/2" chopped 32 shell and grille. Got it from Speedway. It's for their 32 Lowboy roadster kit. They sell a copper/brass radiator for it and an aluminum(Ron Davis brand) rad for it. I got the aluminum unit and it cools my engine fine with a mech fan. It's not perfect, though. An electric fan would be a better choice. I was going for a vintage look. It will creep up around 200* if you idle around a car show.

The shock rockers turn on poly suspension bushings. Just remember to figure your leverage ratios. Mine are approx 2 to 1. That will reduce the shock dampening by half. If you need more info let me know.

Mike

 

[baddawgcustoms]

One of the main reasons that I chose to use a panhard bar was because of the cross steer set up along with the shackles. I wanted to not take a chance of any lateral movement of the axle. As for the set up that you pictured in your third post, I would say that it would work equally well with the rods inward or outward. You are still triangulating with the parallel springs to keep the axle centered. IMHO

Jim

Jim if I weren't so intent on the long leafs up front, I would probably build your front suspension to a T. Pun intended. I bet she drives like a total dream. I'll be posing another question or two in the body section as well. I'm torn between RPM's stretch body, and the Wintec 27 modified. they are about the same size, but 2 different critters. If I go with the stretch 23 I will probably build the front very similar to yours, and if I go with the modified, I'll probably try the design in post 4. Right now all I'm sure of is that I have a nice 289 with a 4 speed and a 9 inch i just bought for the project. Big car show and swap meet in Moultrie GA in a couple weeks, and I hope to fill up the truck with parts. I'll probably decide 2 seconds before I buy the first piece. These posts are trying to help me make that decision. Thanks for what y'all do..

 

[baddawgcustoms]

Baddawg Thanks. That is a 4 1/2" chopped 32 shell and grille. Got it from Speedway. It's for their 32 Lowboy roadster kit. They sell a copper/brass radiator for it and an aluminum(Ron Davis brand) rad for it. I got the aluminum unit and it cools my engine fine with a mech fan. It's not perfect, though. An electric fan would be a better choice. I was going for a vintage look. It will creep up around 200* if you idle around a car show.

The shock rockers turn on poly suspension bushings. Just remember to figure your leverage ratios. Mine are approx 2 to 1. That will reduce the shock dampening by half. If you need more info let me know.

Mike

Thanks for the help Mike. The 32 grill is one thing I am sure of that I want to use. just love the curves of it. Kind of the same reason I want the tall buggy spring in a Model A rear crossmember for the rear suspension. Sort of looks like a woman with a big round behind. LOVE IT.

 

[fluidfloyd]

Baddawg,

The car shown as my avatar had the same suspension in the rear. No spring shackle or panard bar. The lower spring was the lower link and the upper tube link kept pinion rotation in check. All links were parallel with each other. There was very little pinion change throughout rear end travel. I ran this car all through Northern Alabama and Western Tennessee's twisting roads in the mid '60s with no problems. I like these types of suspension front and rear. I say Do It!

George

 

[RPM]

Jim if I weren't so intent on the long leafs up front, I would probably build your front suspension to a T. Pun intended. I bet she drives like a total dream. I'll be posing another question or two in the body section as well. I'm torn between RPM's stretch body, and the Wintec 27 modified. they are about the same size, but 2 different critters. If I go with the stretch 23 I will probably build the front very similar to yours, and if I go with the modified, I'll probably try the design in post 4. Right now all I'm sure of is that I have a nice 289 with a 4 speed and a 9 inch i just bought for the project. Big car show and swap meet in Moultrie GA in a couple weeks, and I hope to fill up the truck with parts. I'll probably decide 2 seconds before I buy the first piece. These posts are trying to help me make that decision. Thanks for what y'all do..

We are planning to be at the Moultrie Swap Meet. If you want us to bring something let me know so we can be sure to put it in the trailer.

 

[fordsbyjay]

You could always use these if you are worried about articulation.

http://www.posiesrodsandcustoms.com/super_slide_springs/featured_products/super-swivel-shackles/

 

[joecool]

I'm not sure if anyone cares or not but I was just on Speedways site and they have their 1/4 elliptics in the Garage Sale section on sale.

 

[baddawgcustoms]

I'm not sure if anyone cares or not but I was just on Speedways site and they have their 1/4 elliptics in the Garage Sale section on sale.

I'm not sure if anyone cares or not but I was just on Speedways site and they have their 1/4 elliptics in the Garage Sale section on sale.

I sure do!! Thank you!!