Rear coilovers

Chandar8

Chandar8

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Las Vegas
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1995 Thunderbird, 4.6
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Does anyone have any experience with rear coilovers in our cars? I ran across a thread on TSTSNBN from 2011 saying that 04 cobra rear shocks would fit, which leads me to belive that something akin to the linked coilovers would, in fact, work. Before throwing cash at the problem I'd just like to consult the hive mind.

juggernautpower.com

VIKING PERFORMANCE 99-04 IRS COBRA REAR COIL OVER KIT

We are excited to now offer a rear double adjustable coil over conversion kit for the 1999-2004 Mustang Cobra IRS application!This kit is offered in two different ride height ranges. The standard ride height will allow ride height adjustment between Factory to 1.5
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Honestly I never got the appeal, they're going to put way more stress on the rear wheel wells, which were never intended to take both shock AND spring load, and they're going to limit rear wheel/tire width. I doubt there'd be any quantifiable performance advantage to them
 
Agreed, the rear shock towers seem to rust on our cars as well, weakening them even more. At least the scp coilovers have a little extra support on the top, but I still don't like the shear point potential at the lower bolt into the control arm. I've got the scp dual adjustable coilovers on the front of mine and they are absolutely amazing. The rear I've got the cobra koni adjustables with eibach springs and that seems to be a great setup so far as well.
 
If you want more spring in the rear, go to the sport springs. That and poly, was so stiff I needed a kidney belt. The poly spring cups really helped.
 
XR7-4.6 said:
Honestly I never got the appeal, they're going to put way more stress on the rear wheel wells, which were never intended to take both shock AND spring load, and they're going to limit rear wheel/tire width. I doubt there'd be any quantifiable performance advantage to them
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The appeal to me is mostly if someone in the future makes fully adjustable rear suspension items. A lot of aftermarket stuff in other cars ends up replacing the A arms that we sit our springs on with 2 individual bars with heim joints in them. Mostly for me it's a 'could this be an option' question over a I'm going to do it question. A lot of my questions in the coming days and weeks will be those lol
 
AdamG said:
Agreed, the rear shock towers seem to rust on our cars as well, weakening them even more. At least the scp coilovers have a little extra support on the top, but I still don't like the shear point potential at the lower bolt into the control arm. I've got the scp dual adjustable coilovers on the front of mine and they are absolutely amazing. The rear I've got the cobra koni adjustables with eibach springs and that seems to be a great setup so far as well.
Click to expand...
Lucky me I live in the desert lol but potentially the coilovers would work?
 
Since nobody has made adjustable LCA in the last 30+ years, I am going to say that probably won't happen. Although I did hear a rumor somebody here was going to make a set out of titanium. 😉

The shock mounting point is only reinforced to the body structure with an additional stamped sheet metal spot welded in place. It would be foolish to think the weight of the vehicle normally held up by the framed section of the body would be as structurally sound at the shock mount without additional material welded in place.
 
Coilovers will work fine; Just use good hardware at the lca. If you can find one or racecougar's rear shock tower braces, they support the shock mount area pretty well too. That area is one layer of sheet metal except right at the shock mount.
 
good info to know. i've been wondering the same thing, would be a good idea to put rear coil overs on my 90. it still has arc ride and I know thats an obsolete item and i'm sure it won't be long before I need shocks/struts so its been in the back of my mind what i'm gonna do for a replacement. i'm not interested in lowering the car (its plenty low enough for me currently)
 
Bill and I discussed the single shear lower mounting issue years ago, but I don't believe anything came of it. I would not run rear coilovers in a single shear arrangement.

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As far as the upper mount is concerned, I agree that the stock structure isn't designed for the additional loading. As many have found out, that area is already marginal for just the upper shock mount. The RSTB's I made won't do much to help. Additional re-work of that area is needed, IMO.


My advice would be to run adjustable coilovers up front if you'd like, but stick to the stock spring and shock arrangement out back. There are plenty of great shock options available for the rear.
 
racecougar said:
Bill and I discussed the single shear lower mounting issue years ago, but I don't believe anything came of it. I would not run rear coilovers in a single shear arrangement.

View attachment 2051
View attachment 2052


As far as the upper mount is concerned, I agree that the stock structure isn't designed for the additional loading. As many have found out, that area is already marginal for just the upper shock mount. The RSTB's I made won't do much to help. Additional re-work of that area is needed, IMO.


My advice would be to run adjustable coilovers up front if you'd like, but stick to the stock spring and shock arrangement out back. There are plenty of great shock options available for the rear.
Click to expand...
I recall you talking about this a few years back. Very good points.
 
The part that worries me is how far the lca can move if it breaks. During a 'general lee moment, a snapping bolt could really make that landing even worse. I've never got one of these completely off the ground,but I've came close.
 
One good question I think needs to be asked before trying to make it work... but I have the feeling this is more a curiosity exploration than anything.

Why?

What limitations from the varied solutions to date related to rear-end handling are you trying to overcome with this idea?
 
Grog6 said:
The part that worries me is how far the lca can move if it breaks. During a 'general lee moment, a snapping bolt could really make that landing even worse. I've never got one of these completely off the ground,but I've came close.
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It's not a good idea in any car, single shear double shear, contrary to the show and movies no car likes the landing lol

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racecougar said:
Bill and I discussed the single shear lower mounting issue years ago, but I don't believe anything came of it. I would not run rear coilovers in a single shear arrangement.

View attachment 2051
View attachment 2052


As far as the upper mount is concerned, I agree that the stock structure isn't designed for the additional loading. As many have found out, that area is already marginal for just the upper shock mount. The RSTB's I made won't do much to help. Additional re-work of that area is needed, IMO.


My advice would be to run adjustable coilovers up front if you'd like, but stick to the stock spring and shock arrangement out back. There are plenty of great shock options available for the rear.
Click to expand...
This is a pretty in depth answer that definitely makes me see this in a different light. The cars seem to be just not built for this sort of thing and short of a space frame in the back it seems more work than it's worth.
 
theterminator93 said:
One good question I think needs to be asked before trying to make it work... but I have the feeling this is more a curiosity exploration than anything.

Why?

What limitations from the varied solutions to date related to rear-end handling are you trying to overcome with this idea?
Click to expand...
It's less of an overcoming of limitations than it was posed to ask if it was possible. With racecougars additions that answer really seems to be no with an asterisk, or yes with an asterisk depending on how you look at it. Largely this is out of the realm of my skill and I am very likely going to leave it be.
 
Find a set of sport springs, do the delrin/poly bushing upgrades, and I don't see you thinking it's not stiff enough. :) The koni rear shocks match the sports pretty well.
 
Chingon1 said:
I’d love to this this to the bird in the future. Cantilever suspension.






View attachment 2061
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I could see someone doing that, but it brings up a similar issue that racecougar was talking about with the lower control arm. Namely the single shear point. I feel like that single shear point with be the greatest point of failure, then having to beef up and manufacture a whole host of other stuff. Solve those problems and it'd be really sweet, but it's the cool factor for that rather than necessity.
racecougar said:
Bill and I discussed the single shear lower mounting issue years ago, but I don't believe anything came of it. I would not run rear coilovers in a single shear arrangement.

View attachment 2051
View attachment 2052


As far as the upper mount is concerned, I agree that the stock structure isn't designed for the additional loading. As many have found out, that area is already marginal for just the upper shock mount. The RSTB's I made won't do much to help. Additional re-work of that area is needed, IMO.


My advice would be to run adjustable coilovers up front if you'd like, but stick to the stock spring and shock arrangement out back. There are plenty of great shock options available for the rear.
Click to expand...


Edit: it'd probably look something like this in our cars.
 

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There are many different suspension designs that incorporate a cantilever .. commonly known as a pushrod or pull rod suspension; depending on the positioning of the components.

Forget shear point - these would not use the shock mounting as a focal point with a perfectly good spring perch. It's just a matter of adding weight and multiple link components to replace a perfectly good shock / spring combo. Unless you have an engineering degree or experience building suspension components .. I'd leave this one alone.
 
I'm with @dDUBb. At this point, build a tube chassis like above, cut body off the subframe and mount it to said tube chassis.
 
What spring rate you running? I can’t stand the progressive vogtland
 
It wouldn’t matter anyway since, they’re identical, Marks have slightly different upper mounting, though I’m not sure it would effect the usage
 
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