Fox rear coil-over vs. traditional spring opinions

Waz900

Member
Apr 22, 2005
10
2
13
Sewell, New Jersey
Hey guys,

I've tried to go through various threads looking for opinions about rear coil-overs vs. traditional springs, but I didn't get my exact answer, so I wanted to post. I picked up a set of used Bilstein struts with the Maximum Motorsports coil-over kit on them for $75. They are in great condition and while I really don't like the idea of used suspension parts, the price made them worth a shot. I need to pick up caster camber plates, so they are on the shelf for the time being. I have seen people post in forums about rear coil-overs not being necessary for street cars and I wanted to get people's opinions. My car is an 88 5.0 T-top car that will almost never see the track. Its a 306 with basic bolt on's for the time being. The suspension is stock (16" chrome ponies) with no lowering components at all yet. Its not a DD, just a weekend cruiser in great weather. Are coil-overs in the rear for my application overkill? I am concerned with added performance, but ride quality is more important to me. I understand that there are additional parts that need to be purchased based on what I go with, but in here I am mainly concerned with the concept of coil overs vs. traditional suspension for a street car. Thanks in advance for your opinions.

Adam
 
  • Sponsors(?)


Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,597
9,883
224
Massachusetts
The use of rear coil-overs depends highly on front spring rates. MM typically recommends a rear coil over spring rate of 150# less than the front spring rate for street driving.

The LOWEST rear spring they sell is 175#. That means the lowest front spring rate is 325# that you can run. That's on the firm side of things for a street setup.

I run a good chunk of the MM catalog in my car, but I do not run rear coil-overs. I have 250# springs up front and they are great for street driving and maintaining a good ride while handling well. I could probably go to a 275# and still enjoy it, but you can see I am far from 325#. Therefore.....I have conventional rear springs.
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,279
2,627
234
74
Dublin GA
lowendmac.com
The shock mounts are less beefy than the spring mounts because they only absorb the bounce and not the constant full weight of that corner of the car. So, what is that going to do long term to the metal in terms of fatigue cracks and stress?
 

2000xp8

SN Certified Technician
Aug 8, 2003
6,992
1,085
194
NJ
Just use a traditional spring.
Call MM and they will pick the set that meets your needs.
Mike is right, you would need a pretty stiff front spring, just to match what is available for the rear.
 

96pushrod

Mustang Master
May 15, 2018
879
533
103
28
Savannah
Rear coil overs are Really not required. One thing that is kind of nice is how much less weight the coilover spring has than the standard spring has due to its size
 
  • Like
Reactions: revhead347

7991LXnSHO

Now I want a 10 year badge
10 Year Member
Sep 1, 2010
3,158
602
164
Kearney, NE
Exactly my first thought, you typed faster.

The height adjustment and weight jacking can help at a track, and the look and wheel gaps can be adjusted for show. But having the top shock mount area broken in the back will not look cool while driving and could be dangerous.

The shock mounts are less beefy than the spring mounts because they only absorb the bounce and not the constant full weight of that corner of the car. So, what is that going to do long term to the metal in terms of fatigue cracks and stress?
 

Waz900

Member
Apr 22, 2005
10
2
13
Sewell, New Jersey
Thank you for the replies, guys. It sounds like traditional springs are the way to go. The one downside to the front coil overs i picked up, is that I don't know the spring rate of the springs. I found where it would be on the spring, but what was etched on there has rubbed off. I've called around to a few speed shops in my area, but no luck finding anyone yet that could test them for me. When i'm ready to do the back end suspension, i'll stick with Bilsteins and reach out to Maximum about what springs to pair them with. I"m getting my car back soon after swapping out the front end due to strut tower rot, so i've got a lot of things to focus on in the immediate future as I put it back together.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,597
9,883
224
Massachusetts
Are they hypercoil springs?

Hope on ebay. Used ones are all over the place for cheap. Buy a pair at a rate that makes sense to you for your needs. If street driving, you will likely be in the 250-325 range. 250 if you have rough roads, 325 if you live where the roads are smooth.

If they are the yellow Bilstiens, i believe they will only provide dampening up to 325#. Any stiffer and you'll need a different strut
 

Waz900

Member
Apr 22, 2005
10
2
13
Sewell, New Jersey
Yes, they are Hypercoil springs with yellow bilstein struts. I'll keep an eye out on ebay, thanks for that. I'm in Southern New Jersey, so our roads get pretty chewed up from salt trucks and the weather. I"d have to research it more, but i'd probably target somewhere in the 275-300 range, based on your information.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,597
9,883
224
Massachusetts
Email MM and tell them what you want to do. They can recommend what rear H&R spring to run. Jack Hidley is a nice guy to talk to.