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I have a copy of a spreadsheet of Spider/GTV spring data that I downloaded many years ago. I thought that it was from the Abb but I have searched in vain trying to find it. So I have attached it to this post. I have updated it with calculations for Vick/IAP and Shankle Super Sport Springs. I don't know if this is worthy of a "sticky". I will leave that to the moderators. Again, I don't want to take credit for this. It is mainly the work of another Alfista. Please PM me if you have additional data that you want me to add.
 

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1984 GTV6, 1973 Berlina, 1987 Milano
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Oh man, I've been dreaming of something like this. Thanks Ed!
 

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Yes, thanks. Any input on the red springs from Vick Autosports?
I bought a set about 10 years ago and they were identical to IAP red springs, in other words very stiff. They could have changed since then.
 

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I bought a set about 10 years ago and they were identical to IAP red springs, in other words very stiff. They could have changed since then.
I think they changed them. I have an email conversation going on with them. Should hear more tomorrow.
 

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Spring rate is proportional to the cube of the wire thickness so that is the parameter that has the most influence. Ask them for that, coil diameter, number of coils and free length and you can compare them with other springs in the data base.
 

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Spring rate is proportional to the cube of the wire thickness so that is the parameter that has the most influence. Ask them for that, coil diameter, number of coils and free length and you can compare them with other springs in the data base.
Stated they are only 10% stiffer than stock and the previous ones were too harsh. No harsh complaints on the new ones. Do I need to do a review?
 

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It would be cool if you measured the parameters that are listed in the data base - wire diameter, etc. I will then calculate the spring rates (and verify their 10% claim).
 

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It would be cool if you measured the parameters that are listed in the data base - wire diameter, etc. I will then calculate the spring rates (and verify their 10% claim).

Even if they're "progressive"?

I'm intrigued by their springs and their claim.

I wouldn't mind being a guinea pig.

Not right now because I'm still doing other stuff on my 78.

Sadly, there are no reviews out there and there seems to be some dissatisfaction with other aftermarket spring that are currently available.
 

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Partially unrelated, but I measured the dimensions of an Alfaholics B set and came to 650 front and 165 rear spring rates. So if someone wants to update the database: feel free.

edited to add: they are also not progressive.
 

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Discussion Starter #12 (Edited)
I have no knowledge of "progressive" springs.
 

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Discussion Starter #14
Updated Excel file

I cannot remember how to edit the file attached to post *1 so here is an updated copy.
 

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Uneven coil spacing makes springs progressive. The closest spaced coils "bind" whilst the spring compresses, thus making it stiffer as it then has less "active" coils.

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Uneven coil spacing makes springs progressive. The closest spaced coils "bind" whilst the spring compresses, thus making it stiffer as it then has less "active" coils.
The calculation for that is above my pay grade.
 

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If you measure your springs to compare them with the database then make sure that you get an accurate wire diameter as it has by far the largest influence on spring rate. Coil diameter is the second most important.
 

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^^ It is also dependent on the material. Grade of steel etc. The same diameter rice noodle and hardened steel will have slightly different numbers.

I'm no engineer, but there are things to know, like stiffness of the wire in Newtons/meter, Young's Modulus in Pascals, the cross sectional area in square meters, and length in meters.

k = EA / L

stiffness = Young's Modulus x Area / Length

"Spring steel is a name given to a wide range of steels used in the manufacture of springs, prominently in automotive and industrial suspension applications. These steels are generally low-alloy Manganese, medium-carbon steel or high-carbon steel with a very high yield strength."
 

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Young's modulus is actually quite similar for many common steel grades, including spring steel. Yield strength, hardness etc do differ greatly, but Young's modulus does not. Which makes life easier when reverse engineering springrates from dimensions.
^^ It is also dependent on the material. Grade of steel etc. The same diameter rice noodle and hardened steel will have slightly different numbers.

I'm no engineer, but there are things to know, like stiffness of the wire in Newtons/meter, Young's Modulus in Pascals, the cross sectional area in square meters, and length in meters.

k = EA / L

stiffness = Young's Modulus x Area / Length

"Spring steel is a name given to a wide range of steels used in the manufacture of springs, prominently in automotive and industrial suspension applications. These steels are generally low-alloy Manganese, medium-carbon steel or high-carbon steel with a very high yield strength."
 
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