31 rear spring free length measurement for a roadster

[old31]

The red book shows free length measurement on a 10 leaf.

What should the rear free length measurement be on a roadster?

[BRENT in 10-uh-C]

Originally Posted by old31

The red book shows free length measurement on a 10 leaf.

What should the rear free length measurement be on a roadster?

The same. All passenger cars used the same front spring.

[CWPASADENA]

Originally Posted by BRENT in 10-uh-C

The same. All passenger cars used the same front spring.

Brent, I think he is looking for the measurement of the rear spring, not the front.

Chris W.

[BRENT in 10-uh-C]

Originally Posted by CWPASADENA

Brent, I think he is looking for the measurement of the rear spring, not the front.

Chris W.

If so, why did he post a picture of the front axle?? If he wanted the rear axle spring, wouldn't he have posted a picture the rear spring??

[CWPASADENA]

Originally Posted by BRENT in 10-uh-C

If so, why did he post a picture of the front axle?? If he wanted the rear axle spring, wouldn't he have posted a picture the rear spring??

I have no idea except he may have had only a drawing of a front spring BUT he does say he wants a measurement for the "rear free length".

Chris W.

[old31]

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Brent, my mistake on posting that picture.

Yes, I am looking for the rear free length.

[rocket1]

41.25 inches eye to eye

[old31]

So what does this tell you?

My 6 leaves from eye to eye measure's 40.5 inches. Is this good, bad, indifferent?

The measurement from floor to underside where the center bolt is, is 15 inches.

[BRENT in 10-uh-C]

Originally Posted by old31

So what does this tell you?

My 6 leaves from eye to eye measure's 40.5 inches. Is this good, bad, indifferent?

The measurement from floor to underside where the center bolt is, is 15 inches.

To be honest with you, it does not tell much. Your spring should actually be comprised of 7 leaves and 1 dummy leaf on the bottom of the spring pack. Even though the leaves may appear to be shaped the same as other springs, there is a thickness difference between applications. I would need to refer to my notes at the shop, but as I recall, certain individual leaves are different by as much as 0.075" ...even though they are the same overall length.

Just to say for comparison that you have two sets of 8-leaf springs that both measure the same eye-to-eye free length does not mean they will have the same compressed height once a load is added if they have different thickness leaves in one or more positions.

[CWPASADENA]

The rear spring for the roadster is only used on the roadster. it is a 7 leaf spring with one dummy leaf. One of the leaves is thinner than the same leaf on other springs. I think it is either the 3rd or 4th leaf. This thin leaf is used only in the roadster springs.

I have the information at my shop, I will look in the morning if I can remember.

Chris W.

[old31]

Yup, Brent and CW you are correct. I recounted my leafs and I have 7.

[BRENT in 10-uh-C]

Originally Posted by old31

Yup, Brent and CW you are correct. I recounted my leafs and I have 7.

But you are supposed to have 8 leaves total. There will be 7 of them that are load supporting and the 8th leaf with be to increase the height of the stack.

[old31]

According to Mikes & A-Springs.

8 leaf = 28-31 Phaeton, Coupe, Sport Coupe, 29-31 Cabriolet 68 A & B, & 30-31 Victoria.

7 leaf = Roadster.

[BRENT in 10-uh-C]

Originally Posted by old31

According to Mikes & A-Springs.

8 leaf = 28-31 Phaeton, Coupe, Sport Coupe, 29-31 Cabriolet 68 A & B, & 30-31 Victoria.

7 leaf = Roadster.

I don't know what to tell you. Here is a list of the part numbers of each spring leaf that makes up the proper Roadster rear spring. Spring Leaf #1 is the one with the eyelets and each subsequent spring # is the next higher leaf in the assembly. The Dummy Leaf is mounted below A-5563-A.

Rear Spring Leaf #1 - A-5563-A

Rear Spring Leaf #2 - A-5565-A

Rear Spring Leaf #3 - A-5566

Rear Spring Leaf #4 - A-5567-B

Rear Spring Leaf #5 - A-5568-A

Rear Spring Leaf #6 - A-5569-A

Rear Spring Leaf #7 - A-5570-B

Dummy Leaf - A-5585


All Roadsters used the A-5560-C Rear Spring Assembly. The 8 leaf spring as you mentioned was a A-5560-B Rear Spring Assembly. If all 8 leaves mentioned above by part number make up the Roadster Spring, and each one are called a "Leaf" by Ford's nomenclature, then the combined total is 8 leaves. If someone else says that it is supposed to be 7 leaves, all I can say is based on Ford records, they are incorrect.

So that you also understand, there were 3 different types of 10 leaf rear spring assemblies. All were 10 leaf in design however they were assembled with a different grouping of spring sizes. On those, you cannot just use any assembly of 10 leaves to make a spring.

[CWPASADENA]

Originally Posted by BRENT in 10-uh-C

I
If someone else says that it is supposed to be 7 leaves, all I can say is based on Ford records, they are incorrect.

Brent,

In the 1928-1948 Ford Chassis Parts Book, commonly referred to as the "Green Bible", on page 189, Ford refers to P/N A 5560-C as "Spring assy (rear) - 7 leaf -----".

You and I both know the roadster rear spring technically has 8 leaves, 7 active leaves plus one dummy leaf which makes a total of 8. However, I think it is easier for the lay person to refer to the roadster spring as having 7 leaves so as not confuse it with the P/N A 5560-B rear spring that has 8 active leaves.

Maybe Ford also came to the same conclusion.

Chris W.

[CWPASADENA]

The "A 5560-C" rear spring used in the Roadsters was only used in the Roadsters and no other model. It had 7 active leaves and one dummy leaf.

The "A 5560-B" rear spring had 8 active leaves and was used in the coupes as well as other models.

You can not actually make a correct "Roadster" spring by taking a a 5560-B, 8 leaf spring and remove the #8 active leaf (the short top leaf) and add a dummy leaf on the bottom. The #4 leaf (#1 being the long leaf with the "eyes") on a roadster spring is thinner than the #4 leaf of a A 5560-B, 8 leaf spring.

The A 5560-B, 8 leaf spring with the top leaf removed and a dummy leaf added to the bottom will come close and work just fine, but it would be slightly stiffer than an original. It is doubtful very many people would detect it as not being original.

My input,

Chris W.

[alexiskai]

I've attached the diagram from the July-Aug '31 service bulletin. You can see that they try to draw the spring assembly accurately. Despite listing it as 7 leaves – which I've tried to number in the image – they also show the 8th dummy leaf, which is located under the main leaf. I've indicated this leaf with arrows. Hopefully it comes through in the attachment.

[CWPASADENA]

alexiskai,

Good information.

While looking at the Service Bulletin you brought to our attention, I ran across a January 1931 service bulletin (page 533) titled "Springs Used Under Model A Cars and Trucks". There is a chart of all the front and rear spring part numbers. Ford listed the A-5560-C as a 7 leaf springs used under the Roadster. They refer to the A-5560-B as an 8 leaf spring used under Coupes, Phaetons, Sport Coupes, Cabriolets and the Victoria.

I also checked the Judging Standards and on page 4-5 (Revision 2016), the Judging Standard has a chart that lists the front and rear springs usage and this chart refers the A-5560-C as having 7 leaves and used under the Roadster. Under "Rear Spring", the written text states "A-5560-C - 7 leaf rear spring used on all Roadsters. It had a dummy leaf (spacer) on the bottom or underside of the spring making it 8 leaves thick----".

Brent,

Since Ford, in several places, referred to the A-5560-C spring as having 7 leaves and MAFCA and MARC in the Judging Standards refer to the A-5560-C spring as having 7 leaves and others in the hobby refer to the "Roadster Spring" as having 7 leaves, May be we can come to the conclusion that the common nomenclature for the A-5560-C Rear Spring is a 7 leaf rear spring for a Model A Roadster,

Referring to the Roadster rear spring as a 8 leaf spring makes it very easy to confuse the A-5560-C spring with the A-5560-B spring which is a 8 leaf spring.

I do not know about anyone else, but I will continue to refer to a Roadster rear spring as having 7 leaves.

Chris W.

[alexiskai]

Found a couple photos of the correct roadster rear spring setup just for reference. Second one is from a-springs.com.

unnamed10.jpg

3310A72.jpg

[BRENT in 10-uh-C]

Originally Posted by CWPASADENA

alexiskai,

Good information.

While looking at the Service Bulletin you brought to our attention, I ran across a January 1931 service bulletin (page 533) titled "Springs Used Under Model A Cars and Trucks". There is a chart of all the front and rear spring part numbers. Ford listed the A-5560-C as a 7 leaf springs used under the Roadster. They refer to the A-5560-B as an 8 leaf spring used under Coupes, Phaetons, Sport Coupes, Cabriolets and the Victoria.

I also checked the Judging Standards and on page 4-5 (Revision 2016), the Judging Standard has a chart that lists the front and rear springs usage and this chart refers the A-5560-C as having 7 leaves and used under the Roadster. Under "Rear Spring", the written text states "A-5560-C - 7 leaf rear spring used on all Roadsters. It had a dummy leaf (spacer) on the bottom or underside of the spring making it 8 leaves thick----".

Brent,

Since Ford, in several places, referred to the A-5560-C spring as having 7 leaves and MAFCA and MARC in the Judging Standards refer to the A-5560-C spring as having 7 leaves and others in the hobby refer to the "Roadster Spring" as having 7 leaves, May be we can come to the conclusion that the common nomenclature for the A-5560-C Rear Spring is a 7 leaf rear spring for a Model A Roadster,

Referring to the Roadster rear spring as a 8 leaf spring makes it very easy to confuse the A-5560-C spring with the A-5560-B spring which is a 8 leaf spring.

I do not know about anyone else, but I will continue to refer to a Roadster rear spring as having 7 leaves.

Chris W.

Before I concede, I want to look at the print to see the name. I am pretty sure that Ford's nomenclature did not call this a 7 leaf spring, ...it called it a Rear Spring Assembly.

Additionally as far as the RG & JS references, I will be very quick to say that there is some nomenclature in the RG & JS book that is not properly named either. That is has been a question I have asked in both revisions about why listing components by an incorrect name as this just adds confusion when comparing to PPLs and S/B info. These JSC guys supposedly have more knowledge than I do (-this was the exact reason I was given by the MARC JSC after I was asked to submit my application yet was turned down is that I did not have enough experience and knowledge in restoring Model-As! ) Like 'whatever'. Is it possible the S/B author for that month made up the 7 Leaves name just like the JSC authors used 'made-up' names like Backing Plates, Firewall, Deck Lid, etc?

The second point that needs to be made is that the Service Bulletins has errors too. Matter of fact, look at Colin's picture of the spring shown in the S/B, and compare to the one he shows in post #19. Similar, but look closely at leaf lengths. Sure makes it difficult to have a "clear understanding" when their picture does not match what the Agency's parts guy is looking at in his inventory. Also, there are part numbers listed in the S/B that do not match PPLs or prints.

The bottom line in this is call it what you wish. If you are trying to tell me that A-5585 is not really a Leaf, then OK. If you want to convince me that the Dummy Leaf is not "active" (-wherever that term came from ) then OK. If Ford's nomenclature called each of those 8 pieces of steel a 'Leaf', then it would seem plausible to most uninitiated that it would/should be considered an 8 leaf spring when assembled as a group. As Colin mentioned the term, if that #8 piece of steel was not a Leaf, then it likely would have been called a Spacer.

And, since the Dummy Leaf does move with the spring on rebound, and it returns to neutral during compression, it does seem it is indeed "active". By the same token, the #7 or top leaf in the assembly is only slightly more active than the Dummy Leaf is, -however that #7 leaf is WAY less active than the #1 and #2 leaf during normal compression & rebound during driving. So it sure makes a valid argument that all 8 leaves are actively moving, and while all are not sharing an equal load, they are an integral part of the spring assembly doing its intended purpose.