The mounted coils are compressed to a certain point or you would be able to just pull them out when the front end is jacked up The only way to compare is to remove the old ones and then compare side by each.
 Even though the coils look identical metalurgy will determine spring rate.

Last edited by Rudi (5/28/2018 12:46 PM)

You really need to use a spring compressor to get the springs out SAFELY.  The best I've found for the early Mustang is one that goes down the center of the spring once the shock is removed.

You want to be careful...compressed springs have an enormous amount of stored energy and lots of folks have been hurt by not working them properly.

BB

yes I used one of those...I gotta tell ya doing it the first time I was stressing it the whole time when the spring was compressed lol

Bullet Bob wrote:

You really need to use a spring compressor to get the springs out SAFELY.  The best I've found for the early Mustang is one that goes down the center of the spring once the shock is removed.

You want to be careful...compressed springs have an enormous amount of stored energy and lots of folks have been hurt by not working them properly.

BB

yes just reading on here and the net knowing it wasn't going to significantly lower the car with the Shelby mod..i was more so hoping the 1" coils would do the trick....I could probably drop another 1" for my taste...maybe when it settles ill get 1/2 of that?..if I do ill be happy with it....I still have to do the passenger side

TKOPerformance wrote:

Yes, its got to settle.  Also, the idea that you dropped the front end 2" by using the Shelby/Arning drop and a 1" lower coil is fallacy.  The drop isn't going to lower the car 1", yet I see that continually bandied about on the internet.  Lowering the upper control arm position has negligible effect on ride height, because the suspension is more complicated than that.  You don't get a linear drop, because you didn't relocate the lower control arm upwards, nor shorten the spindle.  In effect you changed the short leg of a triangle, with the spring mounted on the hypotenuse.  There will be some drop, but its not going to directly correlate to the amount you've moved the upper control arm down.  The reality is more like a 3/8" to 1/2" drop once everything settles out. 

yes TKO I agree its not all linear drop

but I did shelby drop and a 1" shorter spring from Dr Gas or Mr Gas, and the car settled a LOT lower .. almst 2" .. I have a stance now where the nose is lower than the back. 

It got low enough, to have to go with smaller tires, and rolling the fender.. I will be going back to the  stock springs though .Not liking the variable spring ratio and hardness of the ride.

and yes Spring compressors are a MUST!!! I wouldnt recommend doing without them.Around here, the old style dual clamp style compressors are now unavailable in normal auto parts stores. only online. The compressor would have a center spine, with two jaws each side compressinf the spring as evenly as possible. The other style compressors are either not strong enough or arent going to fit your shock tower.

Last edited by Gaba (5/29/2018 1:46 PM)

as far as the wear I can see what you mean..i deff see some after doing 1 spring

BobE wrote:

Regarding the spring compressor, I made my own, using the Ford OEM compressor as a guide.  I used 1/4" plate, a flat plate on the top where the shock mounts mount, heated up (torch) and bent the bottom plate to capture the diameter on the spring.  A 3/4" threaded rod was used, double-nut on the bottom, the nut on the top was tightened to compress the spring, when it cleared the upper arm, the arm was removed and the spring was de-compressed to remove.  Used grease under the nuts and washer.  And kept an eye on the lower nuts to ensure they didn't thread off the rod.
I'll note the this puts a lot of wear on the threaded rod & nut, and is not intended for every day use.  I originally used 1/2" rod, this lasted as a one-time use to remove both front springs.  I do not recommend using 1/2" even for a one-time use.
As other posts indicate, be very careful as when compressed, these springs contain a lot of energy.

With coil springs you have apples and oranges.  The pitch established when winding establishes the total spring length, the coil mean diameter, wire diameter, steel properties, and total number of active coils determines the stiffness.  So, you can have two springs side-by-side that have the same stiffness but one will be shorter than the other.  The shorter spring will have a lower/shorter installed height but will behave the same as the taller spring.  The math is pretty straight forward and the basic equation for a coil spring with constant pitch and constant wire diameter is shown at this site -  https://www.engineersedge.com/spring_comp_calc_k.htm  There is a link to a calculator here - https://www.engineersedge.com/calculators/comp_spring_k_pop.htm 

This exercise is helpful to understand what happens when you start messing around.  For the calculator, enter a value of 11,500,000 for the modulus of rigidity (G), a wire diameter of .625, 8 active coils (this is a guesstimate but typically, the upper and lower coils are fully compressed and not "active" so you can take the total number of coils and subtract 2 to get close.  I used a mean diameter of 4 inches and got a spring rate of 428 pounds per inch.  If you decide to cut one coil to lower the car, this has the often undesired effect of increasing the spring stiffness.  If you change 8 to 7 and recalculate you will see that the stiffness increases to 489 pounds per inch.  In a coil spring you are twisting the entire length of the wire.  When you remove a coil the total wire length is decrease and the twisting effort increases.  Try a few different wire diameters - small changes there can also produce very large spring rate changes.  The modulus of rigidity varies between 11200000 to 11500000 for various spring steels.  It does affect stiffness to a certain extent as well.

So, what is really needed to drop a car is the correct spring stiffness in a reduced total length.  This is done when winding by adjusting the "pitch" of the spring.  A high-end and reputable suspension source knows this stuff and can get you the exact springs you need - some can even get them wound to spec.  A parts-house may not know what they are buying on the open market especially when basing that on price.  So, you may pay a little less but buy 2 or 3 sets with the associated busted knuckles when trying to save a few bucks initially.  Since they often change suppliers on a whim, if someone tells you that they used a site's lowering springs 2 years ago and they worked perfectly is no assurance that the springs you purchase today will produce the same results.

I always put new springs in the press and go to near solid height a few time be fore I check rate. then I go by measured rate to match two that are very close the same rate for each end of the car. Then I shim or use the adjustable spring seat to get ride height. I have adjustable spring seats that go to a min of about .375 inches at the top of one set up that I cut to fit the front of my old mustang that worked great. I got them at Stock Car Products. I'm not sure if the are still in business, but the spring seats worked great. I imagine someone still has them. There is no rubber involved so you get a little noise from them, but that is another reason no mufflers are a good thing.

woah..very interesting stuff..good things to know thank you

GPatrick wrote:

With coil springs you have apples and oranges.  The pitch established when winding establishes the total spring length, the coil mean diameter, wire diameter, steel properties, and total number of active coils determines the stiffness.  So, you can have two springs side-by-side that have the same stiffness but one will be shorter than the other.  The shorter spring will have a lower/shorter installed height but will behave the same as the taller spring.  The math is pretty straight forward and the basic equation for a coil spring with constant pitch and constant wire diameter is shown at this site -  https://www.engineersedge.com/spring_comp_calc_k.htm  There is a link to a calculator here - https://www.engineersedge.com/calculators/comp_spring_k_pop.htm 

This exercise is helpful to understand what happens when you start messing around.  For the calculator, enter a value of 11,500,000 for the modulus of rigidity (G), a wire diameter of .625, 8 active coils (this is a guesstimate but typically, the upper and lower coils are fully compressed and not "active" so you can take the total number of coils and subtract 2 to get close.  I used a mean diameter of 4 inches and got a spring rate of 428 pounds per inch.  If you decide to cut one coil to lower the car, this has the often undesired effect of increasing the spring stiffness.  If you change 8 to 7 and recalculate you will see that the stiffness increases to 489 pounds per inch.  In a coil spring you are twisting the entire length of the wire.  When you remove a coil the total wire length is decrease and the twisting effort increases.  Try a few different wire diameters - small changes there can also produce very large spring rate changes.  The modulus of rigidity varies between 11200000 to 11500000 for various spring steels.  It does affect stiffness to a certain extent as well.

So, what is really needed to drop a car is the correct spring stiffness in a reduced total length.  This is done when winding by adjusting the "pitch" of the spring.  A high-end and reputable suspension source knows this stuff and can get you the exact springs you need - some can even get them wound to spec.  A parts-house may not know what they are buying on the open market especially when basing that on price.  So, you may pay a little less but buy 2 or 3 sets with the associated busted knuckles when trying to save a few bucks initially.  Since they often change suppliers on a whim, if someone tells you that they used a site's lowering springs 2 years ago and they worked perfectly is no assurance that the springs you purchase today will produce the same results.

yea that's what im going to do install both and drive it a lot...if it settles another 1/2" I can deal with it ...I ddeff don't want to be swapping springs lol

6sally6 wrote:

Might try a set of springs for a 6 cylinder Mustang.
Also......sometimes.... IF a car is equipped with AC....the springs will be stiffer. Jus' say'in.
After reading G Patrick's post......sorta....you might be $$$ ahead to find a spring builder and pay the hefty price ONCE instead of 3 or 4 "cheap price" springs and fight with the sprang compressor each time.
I would  install both sides and drive the fool-out-of-it for a few weeks and see where it settles.
You may "learn" to like the ride height considering the hassle of spring swaps.
6sal6