Technical Posies Super Slide Spring

I have a 31.5" Posies Super Slide front spring with reversed eyes that's going under a '30 Model A with the 4 cylinder engine.

Has anyone used this with the banger engine and if so, do you recall what the spring deflection was?

I'm referring to the vertical height change from the top of the spring to the eyes when going from a relaxed state to weight on it, [as in on the ground]
I spoke with someone at Posies and I'm not 100% sure they were understanding my question as they first started out talking about the angle of the hangers and the spring getting "longer" with weight applied. I said I get that, and again asked about deflection.

At first he said 3/4" [which didn't sound right at all] then said 2" which sounded more like it but looking at the spring itself almost sounds like too much.
My reason for asking is I need to replace the center of my crossmember due to some cracking and was thinking about raising it for some additional drop.

[there's a little more explanation and some other unanswered question on page 4 here]
https://www.jalopyjournal.com/forum...etc-build-thread.1341093/page-4#post-15751778
Thanks,
robj

 

Changing the Pocket depth of the crossmember won't change the compression or set ride height of the spring.

 

Too many variables for a manufacturer to give you a hard number. Engines weights are all over the map. Then a thousand other things like fenders, radiators, bumpers, and even the body style will affect the amount the spring compresses. Lots of generalizations could be made, but it’s just not exact.

 

Look up the respective weights of the banger, fatty v8 and say sbc and be guided by that.

If you add lowering when repairing the crossmember if you overdo it slightly it can easily be shimmed back up to required height.

Chris

 

Maybe your using to big a words. Just ask them in their experience how much the spring will settle?

 

Have one on my 32 coupe. Has SBC no fenders. Had to add a one inch spacer to help it set better. Spring is over 20 yrs now. Still sets good

 

The information your asking for is pretty much impossible to get. Although it shouldn't be.

There should be an "average" chart or scale for people to go by. As in: for every 500 lbs this spring settles 1". It's not rocket science and it's really old technology so that information should be made readily available from vendors...

...

 

I don’t have an answer, just a question.
Are you referring to the stance, or driving down the road for how much it changes?

 

I take it he wants to know static height of the spring loaded. As in at 1500 lb load the spring settles 2", at 2000 lbs it settles 2 3/4" etc.

This way he could set height on crossmember somewhere close to get his ride height with the new crossmember installed.

Same thing I tried when I welded in my front crossmember and came up with absolutely nothing on spring deflection numbers. So I made WAG decision...

...

 

Is the Posie phone number not working?
POSIES 1928-34 Ford front SuperSlide Springs are the industry standard for ride quality and ride height choice. Designed specifically for today's Hot Rods, these springs feature friction reducing SuperSlide ****ons, three ride height choices and spring rate options to allow your ride to have the best performing front suspension on the road.

Our #1001 series, 31 1/2", eye to eye spring, is designed to be conventionally mounted above any Stock Early Ford Axles that have a 36 1/2" perch boss distance or 34 1/2" between spring perch eyes when used in behind the axle installations.

1001 Series Options:

Reversed Eye - Most popular configuration for small block engines. Features 3 1/4" free arch. Works best with fendered cars, lowering the front end without any clearance issues.

Low Reversed Eye - 1" Lower than our reversed eye spring. Features 2 1/4" of free arch. Works best with Hi-Boys and fenderless cars for the lowest riding multi leaf spring available. Frame will need notched above spring for clearance

Stock Eye - For those cars not needing to be in the weeds or where additional ride height is desired, our stock eye version features 4 1/4" of free arch.

Reverse Eye Heavy - Same configuration as our reversed eye spring but with increased spring rate for use with Big Block, Blown or Hemi engines.

NOTE: When using a dropped "Stock Ford" axle we recommend using our #1002 series 31" Spring. When the axle is dropped, the perch distance may be slightly narrower after modification. The 1/2" narrower springs fit better.

Product Details:

Weight: approx. 22.0 lbs.
Packaged dimensions: 35 x 6 x 9

POSIES SuperSlide Springs are made from premium tempered steel. Each spring features POSIES exclusive SuperSlide moly-nylon ****ons that eliminate metal-to-metal friction for a softer, quieter ride. Hand-***embled and tour-tested on cars logging over 100,000 miles, these springs offer proven reliability. Proudly made in the USA!

 

All that info is fine and dandy for advertising purposes but no real info there for the builder.

Free height is basically worthless info, what's needed is loaded height, this alone would give the builder more info then what's in that entire write up....


....

 

A very good point! Maybe that was the issue.

I just figured they would know how much it would "settle"[ ie. deflect] with a Model A engine. It just seemed like a question they would or should have an answer to.
I didn't mention no fenders, no bumpers as I didn't want to confuse things and I figured I could make a mental adjustment for that.

To clear things up, [at least I think] I'm looking for the vertical height between the eyes and the top of the spring between loaded and unloaded with a 4 banger.

Does their reply of 2" sound plausible? Unloaded the height from the eye to the top of the spring is 5".


2" looks like it could be about right, I guess. Obviously it will deflect the most at the far ends. But the more I look at it, 2" seems like a lot...

robj



What do you think?

robj

 

Yes. This is called spring rate. Coil springs will list the rate, kind of half correct when they are called 200, 300,400 pound springs. Place 200 pounds on top of an unloaded 200 pound spring and it settles
One inch. Spring rate is pounds per inch.

I don’t know if leaf springs are constant rate, or variable rate, but this should be measurable for the manufacturer. If you look at leaf springs sold for circle track racing they usually list a spring rate.

You could measure it CAREFULLY yourself in a fixture that would hold the spring in the intended configuration in a large hydraulic shop press, and some means to measure the load. I picture an I-beam with gizmos to hold the shackles like on your axle. The I-beam would rest on one pad of your car scale system, say a 4 scale set with 1500 pounds per pad. Then load the spring with the press, measuring deflection from unloaded to say 3 inches of deflection, measuring the load for each inch of deflection. If the load increases in equal increments per inch of deflection, you have the linear spring rate. If it increases or decreases load per inch of deflection, then you would have a nonlinear spring.

It would be a lot of work, and you would have to be careful to not have any problems like the spring leaving the fixture in an explosive method. There would be a lot of stored energy in it once loaded.

 

@Dave G in Gansevoort

I was thinking along the same lines, take a big flat plate with a type of floating plate at one end. Turn the spring right side up with 1 spring eye sitting on plate, the other spring eye on the floating plate. A jack in the middle on the center bolt, measure height and with a pound pressure gauge mounted between jack and spring then pump jack until you get say 1000 lbs pressure and read height, add 500 lbs and read again, then say work up the scale to 2500 lbs and take height measurements.

I've watched a lot of you tube videos of guys checking strength of different items using these pressure jacks.... wish I had access to one just for a couple hours....

...

 

A 1-1/8 inch diameter cylinder is almost an exact 1 square inch area. A hydraulic cylinder that diameter could be used with a pressure gauge and the pressure reading divided by the area gives force, ie load. I wonder if bottle jacks are available with a 1-1/8 inch diameter…

I could use the same data for a Posie’s spring. Maybe I’ll try building something…

 

Leaf springs are progressive in rate, not linear. As the spring compresses the spring rate in Lbs./inch of deflection gets higher (stiffer). As the shorter leaves of the spring become more flexed the spring rate will increase.

This quote from a few posts back seems wonky to me.....
NOTE: When using a dropped "Stock Ford" axle we recommend using our #1002 series 31" Spring. When the axle is dropped, the perch distance may be slightly narrower after modification. The 1/2" narrower springs fit better.
The additional drop of a beam axle is done outboard of the spring perches so why would the spring perch width change? I don't see how a dropped axle should need a shorter spring when measured eye-to-eye.

Lynn

 

Even more of a reason to measure the rate of the spring. A simple fixture could be made to measure the rate using a 4 ton bottle jack with some modifications to the jack. It appears that most 4 ton bottle jacks are almost perfectly 1-1/8 inch diameter for the ram. Just have to figure out how to measure the cylinder pressure under load. I might attempt this for my own edification. You can take the engineer out of the lab, but you can’t take the lab out of the engineer, I guess…

 

1001 Series Options:

Reversed Eye - Most popular configuration for small block engines. Features 3 1/4" free arch. Works best with fendered cars, lowering the front end without any clearance issues.


Is the Posie phone number not working?
POSIES 1928-34 Ford front SuperSlide Springs are the industry standard for ride quality and ride height choice. Designed specifically for today's Hot Rods, these springs feature friction reducing SuperSlide ****ons, three ride height choices and spring rate options to allow your ride to have the best performing front suspension on the road.

Their phone is working and as I said at the beginning of my post, I spoke with them. Details in the post.
And yes, I read all of that information and as I said I have the reversed eye spring.

Reversed Eye - Most popular configuration for small block engines. Features 3 1/4" free arch. Works best with fendered cars, lowering the front end without any clearance issues.

I'm not sure what this, "3 1/4"free arch actually means. Any ideas?

The difference between the total height unloaded, [5"] minus the deflection they report, [2"] leaves close to 3.25"
But I'm guessing that's with a SBC.

So a SBC weighs 575 lbs + or -, and the Model A banger is 350 lbs. A big difference.
So if that's what posies was gauging their 2" estimate on I'm thinking it will deflect much less with the 4 banger.

I think my head is starting to hurt...
robj

 

To be honest, I was really hoping for some real life data. Like someone that's used the same spring with a 4 banger. How much did it settle/ deflect. Using a press to measure spring rates is getting a bit beyond my pay scale...
robj

 

Free Arch is the term used for the arch when the spring is unloaded (off the vehicle).

Loaded Arch is when the spring is under load (on the vehicle with weight on the springs).

The difference in these measurements is what you are referring to as "settling" and trying to work out.

 

All Cast iron sbc ,
copper Rad
Steel renders
Bumper
Metric disc
Vega box
No hood

Front axle another scale

 

Try it. It takes less than an hour to swap the spring out.

Modifying the front crossmember will give radiator clearance problems. It already virtually sits on the top clamp bracket

 

Remove a leaf if to stiff
Or shorten 1 or 2 ,
& change spring spacer
To raise or lower
Some time Trial and error,
Or mock up , weigh front axle when completed engine ect ,
Then adjust spring with methods described above, ark spring , press &
Force / presser gauges .

 

I thought about that quite a bit. It doesn't seem to make sense but I think it is a thing?

When I spoke with Okie Joe about the axle being dropped and stretched [for mechanical brakes] he mentioned the 31.5" axle.
robj

 

No it’s not a thing. If the axle is dropped and the kingpin bosses are allowed to narrow, it does nothing to the spring perches. I can’t figure why in the world they would write such a statement.

 

Thanks for that!

So Posies is saying 3.25" Free Arch. And when I called they "sort of" said the spring would settle 2".
But in their notes for this spring they say works with a small block, full-fendered vehicle.

So I'm thinking engine difference between SBC and banger, 225 lbs. lighter.
No fenders, no bumpers, 1/2 hood, maybe another 200 lbs?
So around 400-425 lbs lighter for my application which in my mind is quite a bit.

Applying some "Kentucky Windage" and the theory of what looks right probably is,
I'm thinking I can remove both of the short top leaves as I don't think I have enough weight that they will ever come into play.
What I am going to do is put a shorter single piece I cut from the old spring on top to reinforce the very center of the top remaining spring where the bolt hole is located to avoid stress/cracking in the center.


In addition, as you can't really shorten a Super Slide Spring, and with a 400 lb. + or - weight difference I think I'm safe in removing 1 leaf. The one I'm taking out is the 2nd one up from the main leaf. [with the X] The remaining leaves are then more or less equal distances apart.
Obviously this can easily be adjusted but I'm thinking this will put me in the ballpark.



Next up is figuring how much I can raise the center of the crossmember and modifying the angle of the caster to account for the rake.

robj

 

Two short top leaves gone, replaced by a short one.



and the second leaf removed. I'm thinking it looks 400 lbs better. And the leaves more or less symmetrical in length.


I'm going to call it good... Until it isn't.
robj

 

Here is a data sheet I received from Posies for a rear spring (if I attached it correctly). They should be able to provide one for any of their other springs also. It shows the deflection and stretch with loads.

 

Well isn't that interesting. Thanks!
I'm wondering why the guy I spoke with didn't offer to send me that. Or better yet, why there isn't a link to that on their web site when you click on "information" on each spring. It would probably cut down on their phone calls.

I was actually looking at their reverse eye Model A rear springs last night.
Can I ask what you are putting the spring under? And I guess also why the narrow width?

I haven't done a lot of research on the rear yet [or measuring] but I'm guessing I would need the 48.5.49.5 stock width.
I have a 30' Tudor but I have no clue what the load would be. I've read the Tudor body weighs around 700 lbs but obviously not all of that weight is on the rear.
robj