Hi guys

A while ago I bought 2 pcs of NOS 8 leaf front springs from DC

From the outside they appear to be the same, eye to eye distance is the same, eye centre to axle mounting surface they have the same height, same number of leafs same thickness of each leaf and each leaf has the same length

so far so good

BUT???

today I took them appart after painting the outside, to lubricate the mateing surfaces

In one of the springs, all the leafs has pretty much the same arc, just a slight progressive increase in arc size when going from main leaf to the smallest one. This makes it quite easy to assemble and dissassamble

The other one, has an almost flat mainleaf but then the other springs are more curved .... this makes it much more harder to assembly and dissassamble the spring as it needs to be compressed to get the springs to seat into eachother..

Now to the question. Will this affect the spring rate??

according to the matematical formula for calculating the spring stiffness the only parameters that counts is:

spring length (eye to eye)
number of leafs
leafs thickness
leaf width
Youngs modulus of steel

so these parameters are the same for both springs, so I guess they should have the same spring stiffness???

The only reason I see why they would make this difference in design state is that the mainleaf will become almost in an zero bending stress state when the spring is under load. Ie making the spring safer pushing the bending stresses from the mainleaf to the following leafs.

As of the equally arced spring all the spring will be subjected to the same amount of bending stresses, making the main leaf more prone to crack as it is always subjected to bending stress.


So what do all of you guys think?? I would really need some expertise help on this one.

Should I try to talk to DC or should I moiunt the on the frame and place the neigbours on the left and right frame horn to see if there is any difference??

Thanks for any feedback

 

I would bolt them in and run them. Its a truck with a straight axle and leaf springs, does spring rate really matter?

 

I would call and see. Don't know if I would use it, just my 2 cents which is only worth 1/2 a cent.

 

No spring expert here but from your description my common sense tells me the spring rates will be different. Whether that makes a difference in ride height and/or handling characteristics remains to be seen. If it was my truck I'd feel better if the two springs were identical but that's just me.

 

I would also want them identical, but I am starting to have a really bad experience with front springs and US suppliers

First I ordered a set of new stock ride height springs from a reputable company. 3 months later they showed up......they where lowering springs

well some back and forth they sent me new springs.... 3 months later after alot of this and that they where the correct partnumber but where still lowering springs

Then I told them to take a hike

and turned to another reputable firm and ordered a set of NOS springs with identical ford TAAA part number, witch now turns up as not being fully identical.

Now we are 1 year from my first order.........

I am starting to have serious doughts about the suppliers competence.....

 

I have no personal experience but I have read positive comments on this forum about springs from JC Whitney.

 

Ok

this seems to be the deal

I called the NOS department at DC and they told me that the spring that has the (pretty much) same curvature on a leafs and has the partnumber stamped in is what the truck came with when it left the factory.

The other spring that has different curves on each spring was a part replacement spring that ford used when the truck came in to the repair work shop with a broken spring.

So both seems to come from Ford but they are years appart.

He also told me that I should not feel any difference in them.

This just enhance my thaught that they are designed in a nother way to take some of the stress of the main spring and second one to make the spring less prone to cracking hence making it safer.

I will let you all know when I have them mounted to the chassie, and made some test to see if I achive the same frame height with same load.

They only had part replacement springs left..... so I m thinking about ordering on anyway........

We´ll see

 

TAAA-5310-A .. Front Leaf Spring-8 leaf / Obsolete

1953/56 F100.

CARPENTER NOS OBSOLETE PARTS in Concord NC has 6 = 800-476-9653.

 

JCW used to sell Eaton springs, at a very good price and good price on shipping, but they don't any more.

Jim, I am skeptical of DC's explanation, as far as it goes. In the mid-'50's, the whole leaf spring industry changed the type of steel used. It undoubtedly resulted in some changes in the construction of the springs, and in the amount of arch used. So if the Service Replacement spring was later manufacture, it might well not be identical to the early type. Here is a good discussion of the changes and includes some interesting links: Eng-Tips: Automotive Engineering other topics - Can lubricant actually damage spring steel?

I agree with others that you could try it before hitting the panic button.

 

Thanks for the thread. It was some interesting reading.

I will check the springs I have when intalled in the chassie.

However I have a container leaving San fransisco In the end of oktober, where I can tag along. So I guess I will order yet another spring just to make shure I have an identical set.

It should probably work with the springs I have but I really dont like the thaught of not having two identical front springs! I like perfection......

it´s a sickness

an expansive sickness unfortunatelly

I am not really happy with DC scense of details in this issue

even if they "may" work together