Technical dead perch

I learned what a dead perch is, does that count.

 

2 front springs are not the same thing as a buggy spring in front, apples and oranges. Totally different dynamics.

 

no shit.
the post was an example of how to test the movement.

 

Does anyone use a dead perch on the rear with a transverse spring? Wouldn't it work the same as in the front?

 

Well here's another point of view from my experience: I run Vega cross steering without a panhard bar or a dead perch. I've driven the car over 7,500 miles so far and I've never experienced any bump steer, wobbles, wiggles, vibration, or any other ill-handling. My spring is fairly flat, so maybe @alchemy 's theory above about a flat spring reducing side to side movement is accurate? I'm not recommending that you forgo the panhard bar or the dead perch, I'm just saying that this guy doesn't run either and has had zero issues.

 

What was the question?
That should cover all the bases!

 

Hi DDDenny

 

I think we all know the reason for the use of the dead Perch and panhard bar is to prevent the drag link from pulling the front end to the steering side.

 

Chocolate or Vanilla?

 

So why didn’t Henry Ford use a dead perch ?
Did Ford preload/pretension his spring, so as to affect the handling somehow ?
I am curious as I have not used either a dead perch or a panhard rod, yet to my mind the vertical sliding fork thing in the centre of the axle seems to be the best solution, (yet I have not used that either).

 

Henry used a side steer box on the early set ups.

 

Geez, How's I get dragged into this shit storm...but since I did, let me add some more fuel for the open minded..

Have any of you considered things like typically seen unnecessary heavy caster, or that, combined with a scrub error as having anything to do with the topic here?
.

 

I don't know what this method is called either, but here's a particularly tidy execution from my buddy Jim Stewart – you're looking at the back of the axle and the the slotted piece is welded to the axle. The pin is welded to the cross member. Add a Delrin bushing and you're good to go.

 

I think the flat spring is most valuable in reduced sideways movement on car with a dead perch. A shackle with a shallow angle would be most valuable if the car didn't have a dead perch. A shallow shackle wouldn't allow as much side sway.

As to the post about Henry Ford not using a panhard or a dead perch: Henry first used cross steer in the Modern Era (yes we know T's had it too) in 1935. His first application of any form of sway control was the Deluxe '40 and it's front sway bar. It wasn't until after the war (I think it was on '46's) that he actually installed a panhard bar in front. I don't know how he got away with all that horrible front end sway for that decade of production. Maybe he kept his shackle angle shallow?

 

Seen it done using a skateboard wheel

Sent from my moto g(6) play using The H.A.M.B. mobile app

 

Here's mine made from a Citreon 2CV track rod and steering arm

 

You have the feet of a surgeon!

 

Haha!!! Protects my Converse from oil and grease

Sent from my moto g(6) play using H.A.M.B. mobile app

 

I thought that cross steer was used on some of the later cars with wishbones?
Am I wrong that Ford had cross steer on some cars with wishbones ?

I think alchemy answered this above.

 

D-Russ, That is very well done, never seen it with the pin solid and the plate moving. Kudos to Jim for that. Another way to do it was the Allards split axle very similar to later Fords' twin I-beam which was a great idea for selling tires. The Allard kept the transverse spring however but I imagine the whole thing was a camber nightmare.

 

No, you're not wrong, the 46 - 48 cars had wishbone suspension with cross steering, and a panhard rod. They also have the spring in front of the axle, where the spring is not under tension. Earlier cars ad the spring over the axle, and it was under tension. Apparently having the spring under tension reduces the need for a panhard rod, though I'm not an expert on this technology, just repeating what I've read posted in other threads.

 

Blues, what do you mean a "spring under tension"? Isn't the whole theory of a spring is it is under tension? That's how springs work, they use pent up force to push back at the axle moving upward. How does a spring in front not still have tension?

 

Spring spreader bar..Tool for installing spring..Because they can't reach the shackles unless compressed or use of spreader bar [which makes them longer] and once "shackled" and spreader bar removed they are under tension..Ford had it figured..Sway bar in front came out in 1940, sway bar plus panhard in 1941 and stayed thru 1948..Rear panhard may have started in 1946 and carried through 1948 but 1948 defiantly had a rear [along with front combo] panhard bar..

 

Well, I wish I could answer your question properly, but as I admitted in my post, I was just repeating what I have read in other threads. I did a quick google search and found this, see post #7 from @pasadenahotrod in this thread: https://www.jalopyjournal.com/forum/threads/front-panhard-bar-on-36-ford-straight-axle.452410/

Maybe he can check in and clarify it for us. Maybe I completely misunderstood his post in that other thread.

Also, see post 11 from Dick Spadaro

 

You don't need a panhard bar if everything is set right and tight. Fords never used one from 35 to 46 and they steered off the right side pretty damn good.

 

I'm sure someone has beat me to it but here's a dead perch. HRP

 

All early race cars with transverse springs had dead purches, we're talking buggy spring ride, if you like it do it. Indy cars, sprint cars, midgets all had this setup.

 

Yes, and they only turned left !
Because they turned left, their "dead perch" was on the left side.
On a street car with cross steering if you are using a "dead perch" it should be on the right side of the car.

 

Thanks, Pete. Dead right...as usual. Dead PERCH right.

 

I take this to mean under ‘preload’ as in spring eyes forced apart to reach shackles in horizontal position, ‘before’ the weight of the chassis and engine are lowered onto it.
Most say it doesn’t need preload, some say it does.
I was always told to put preload into a spring, and believe this is why they are so dangerous when pulling them apart.
I also, to my way of thinking, suspect that the car would handle better with preload.
I have asked this before, but never got definitive answers.

Clemens.