85 gt springs vs.factory mont

**CanyonGT** · 04-15-2009, 05:51 PM

my fairmont rear springs are shot would stock 85 gt hatch springs raise it some? i got some gave to me for free is why i am asking. thanks matt.

**Gerald Wiese** · 04-15-2009, 07:28 PM

I think mustang hatch springs are 200/300 variable rate ......if they are newer they should help the sag.

**CanyonGT** · 04-15-2009, 08:47 PM

thanks man.

**MAD MIKE** · 07-28-2009, 11:05 PM

**David Claflin** · 07-29-2009, 07:26 PM

Originally Posted by MAD MIKE

Do you by chance have any info on 85 LTD LX rear springs? I've got a set of stock mustang GT springs as well, and would like to see how the rates compare to the LX.

**CanyonGT** · 07-29-2009, 08:04 PM

thats nice to know thanks

**MAD MIKE** · 07-30-2009, 05:51 AM

Originally Posted by David Claflin

Do you by chance have any info on 85 LTD LX rear springs? I've got a set of stock mustang GT springs as well, and would like to see how the rates compare to the LX.

Same as Fairmont(excluding wagon) use 8597 or CC821.
What year GT? You may have one of six rates with the Mustang/Capri.

**Greywolf** · 07-30-2009, 06:32 AM

Mike,

Didn't the LTD LX have different spring rates from the regular LTD? Although the applications are the same in the moog/trx/etc catalogs, I'm pretty sure Ford gave them a different part number; perhaps the LX was uncommon enough to just get lumped in with the other LTDs by the aftermarket?

After work I'll fire up my Ford catalog and look.

Ben

**MAD MIKE** · 07-31-2009, 04:18 AM

Originally Posted by Greywolf

Mike,

Didn't the LTD LX have different spring rates from the regular LTD?

The rear weight will not change much between 4dr/5dr Fox Chassis models. I don't see any reason for Ford putting a higher spring rate in the rear. The easiest way to stiffen up the rear on the quadrabind would be to use a sway bar.
As for the front, the LX is a different rating from the other LTDs. They are rated at 415lb/in where the others are rated at 383lb/in. The only difference amongst the other LTD listings is free height and load ratings.

Originally Posted by Greywolf

Although the applications are the same in the moog/trx/etc catalogs, I'm pretty sure Ford gave them a different part number;

The LTD LX front spring does have its own listing. 8598.
Being a touring car I would think the sway bar in the front would also be upgraded.

**MAD MIKE** · 09-12-2009, 04:35 AM

**JACook** · 09-12-2009, 05:57 PM

Originally Posted by MAD MIKE

The rear weight will not change much between 4dr/5dr Fox Chassis models. I don't see any reason for Ford putting a higher spring rate in the rear. The easiest way to stiffen up the rear on the quadrabind would be to use a sway bar.

A stabilizer bar does not increase spring rate. What it can do is increase the
effective wheel rate on the outside wheel, when cornering. But that's not the
same thing.

A station wagon will normally have a substantially higher spring rate than it's
sedan equivalent. Station wagons do have more rearward weight bias, but the
bigger consideration is with how they are typically used. A wagon can carry
far more cargo than a sedan, and they tend to do so much more often. When
carrying cargo, spring rate matters more than anything.

Few Fox wagons ever came from the factory with rear bars under them.

BTW, Fox rear suspensions only bind when people modify them in ways they
shouldn't.

**MAD MIKE** · 09-12-2009, 09:01 PM

Originally Posted by JACook

A stabilizer bar does not increase spring rate. What it can do is increase the
effective wheel rate on the outside wheel, when cornering. But that's not the
same thing.

In a perfect application, yes. But we are talking Fox Chassis

.
I didn't say it would increase the spring rate/load capacity

, it does change the feel and does stiffen(through bind) the rear. The counteracting effect with the swaybar leveraging against the opposite control arm and spring does create the effect of a stiffer suspension. Over a speed hump you may not notice, but uneven dips the suspension will feel stiffer.

Originally Posted by JACook

A station wagon will normally have a substantially higher spring rate than it's
sedan equivalent. A wagon can carry
far more cargo than a sedan, and they tend to do so much more often.

I disagree.
Load Capacity is the difference, not spring rate. 8597 and 8599 have fairly close spring rates, the biggest difference is in their load capacities which is 200lb per spring. This often correlates with a taller free standing height and/or thicker coil wire. The car may sit higher empty, but when loaded it will still have the same spring rate and ride comfort when empty.
A wagon can definitely hold more volume in its interior than a sedan, that's a given. But both still share the same chassis.

Originally Posted by JACook

When carrying cargo, spring rate matters more than anything.

A cargo spring changes rate exponentially throughout travel. This is great for counteracting heavy weight in the car over large dips and bumps, where a linear spring may bottom out.

Originally Posted by JACook

BTW, Fox rear suspensions only bind when people modify them in ways they
shouldn't.

You mean like how Ford added a rear sway bolted directly to each RLCA

Which are not parallel links. With the links level to the chassis rails pointing straight back, the ends of the arms are farthest from each other. Bound the axle up past this and the arms begin to get closer, same in rebound. If the arms were long enough and could rotate 360* ,on their chassis mounting point, they would hit the driveshaft.

**JACook** · 09-13-2009, 07:33 PM

Spring rate is defined as how many pounds of load it takes to compress the spring
one inch. Rate is determined by the tensile strength and diameter of the spring wire,
and the number of active coils. Now, when the spring is not directly over the axle,
there is a bit of geometry involved to get the actual wheel rate, so you can't
just look at the chart and know what your wheel rate will be. But the fact remains,
the spring rate is the -most- important factor to consider when selecting springs
for either performance, or load carrying. The free length of the spring is simply
a by-product of how much preload you need at a given spring rate, to achieve
your desired ride height.

Cargo coils are just a marketing term for variable-rate springs. All variable-rate
springs work on the principle of reducing the number of active coils as you increase
load. Variable rate springs allow a softer ride when lightly loaded, then when you
add load, the closer-together coils stack. This causes the remaining coils to do
all the work, which increases the spring rate.

This is all pretty much "spring 101" stuff here, you can look it up in any text book.

I'm not sure why you consider a stabilizer bar as causing bind. A stabilizer bar
is nothing more than a torsion bar, or in other words, a linear spring. It's job is
to transfer load from one side of the suspension during cornering, to the other.
Being a spring, it has a linear spring rate. Suspension bind is characterized by
a non-linear buildup of effective rate.

Whether the stabilizer is bolted directly to the control arm, or tied to it using links,
doesn't change how it does it's job. The fact that Ford bolted the Fox rear bar
directly to the arms does not induce any bind, it's just the most expedient way
to get the job done. You might want to study how Ford chose to form the ends
of the bar the way they did, and bolt it inside the arms, rather than just using
a couple simple bends, and bolt the bar to the outside of the control arms. (The
way the bar is formed allows it to twist in multiple axes.)

**David Claflin** · 02-26-2011, 01:11 PM

Michael, where did you get the moog catalog from? I looked on Rock Auto and they sometimes list the heights and wire diameters, which is helpful, but they don't list that info for all springs. I looked on the Moog website, but didn't see anything about a catalog....

**MAD MIKE** · 02-27-2011, 04:48 AM

Originally Posted by David Claflin

Michael, where did you get the moog catalog from?

The old fashioned way, I asked for one.
There are no mystical magical springs for the F-C. It does not cover all makes/models/years either.

**David Claflin** · 02-27-2011, 09:58 PM

Thanks, my son took his old springs out of his 94Gt, and I was thinking of using his rear springs. I'll also see if there's a way to determine spring rate from the WD size and height info.

**MAD MIKE** · 02-28-2011, 12:21 AM

Originally Posted by David Claflin

Thanks, my son took his old springs out of his 94Gt, and I was thinking of using his rear springs. I'll also see if there's a way to determine spring rate from the WD size and height info.

**mcb82gt** · 03-01-2011, 08:38 AM

Originally Posted by David Claflin

Thanks, my son took his old springs out of his 94Gt, and I was thinking of using his rear springs. I'll also see if there's a way to determine spring rate from the WD size and height info.

Most of us cougar/bird guys were using those springs in the rear. It dropped it pretty good. Maybe too much for me, some were using adjustable rear lower cont arms to get the ride height dialed in for them.

**David Claflin** · 08-01-2011, 01:53 PM

Originally Posted by mcb82gt

Most of us cougar/bird guys were using those springs in the rear. It dropped it pretty good. Maybe too much for me, some were using adjustable rear lower cont arms to get the ride height dialed in for them.

I was just looking at the moog site and what I've found for spring numbers at rock auto and the rear spring for an LTD LX is the same as what they show for the rear of an 85GT of the same year.

**David Claflin** · 07-15-2011, 09:39 PM

Just as a gee-whiz for this, if you put the spring number Michael loaded into the search bar on Moogs site you can get all the info you might need about the springs. It's at the bottom of the page.
http://www.moog-suspension-parts.com...rod=MOOG-CC821

**ratio411** · 08-02-2011, 12:50 PM

That wasn't the 'Moog site'... It was an "independent Moog parts dealer".

Here is the Federal-Mogul tech site:
http://www.fme-cat.com/

**David Claflin** · 08-02-2011, 02:52 PM

Originally Posted by ratio411

That wasn't the 'Moog site'... It was an "independent Moog parts dealer".

Here is the Federal-Mogul tech site:
http://www.fme-cat.com/

True, but that information is still correct as far as I can tell.

**LTDScott** · 08-02-2011, 01:21 PM

Interesting that this topic has come back to life. I'd like to go with stiffer rear springs on my car but most Mustang springs are too low. Might have to check out the Moog catalog to see what options are out there.

**David Claflin** · 08-02-2011, 02:50 PM

Originally Posted by LTDScott

Interesting that this topic has come back to life. I'd like to go with stiffer rear springs on my car but most Mustang springs are too low. Might have to check out the Moog catalog to see what options are out there.

The coils on the wagon were .589, while the LTD LX were .620
The 823 are substantially stouter then the 821 that come stock on the LX. Rock auto lists the 823, 821 and the 8597 as replacementss for the rear of an 86 LTD. I imagine the wagon would normally have the 823's but the coil diameter is too small on mine.
For what it's worth the H+R race are close to the standard LTD LX springs, in rate from what I can tell, they are 11.5 free standing whereas the LTD LX are 12.29.

**BRWSaver** · 08-04-2011, 11:05 PM

Originally Posted by LTDScott

Interesting that this topic has come back to life. I'd like to go with stiffer rear springs on my car but most Mustang springs are too low. Might have to check out the Moog catalog to see what options are out there.

Oddly enough I have found that Amazon.com has the most complete "what else does this part fit" listing for these springs. I pulled a set of Thunderbird V8 springs out of the junk yard for use on the Lemons Futura after a long search of the internet. The Moog 8599 spring used in the back of the Fairmont wagons is also a stock Tbird part, and seems like the stiffest of the factory options.

Which brings me to my next question: Anyone know the stock ride height? Either the factory spec, and where its measured, or just with a tape measure to some standard point with stock springs and tires. I don't need to be super exact, but my car was lowered with a torch before I got it and I want to know where it sits now in relation to that.

Woody

85 gt springs vs.factory mont

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