Dual mount Front and Rear Springs and Sway Bars

Sky65

Well-known member
Joined
Aug 27, 2008
Messages
185
Location
Maryland
What sway bars do you all recommend with front and rear dual mount springs on a SB 65. I'm currently running a VBP front bar 1.125 and no rear bar. 17X8 255/50 front and 17X9 275X50 rear. Shortened 460 ft coils and 300# rear spring. The VBP full kit comes with both bars but my experience is the rear is not necessary. Daily driver but I like to throw it around every now and then.

Thanks
Tom
 
Thanks. That's what I'm thinking too. I have a VBP full kit to put on the car. I think I will try it without the rear bar first.
 
I would really like to see someone test this on a dual mount. Put a load on one end and see if you get any movement on the other end. That would tell you if the spring is acting as a sway bar.
 
I can't say about the front end, but I can tell you from real life experience that in back you do NOT want to run a sway bar with a dual mount (unless you get a kick out of losing the rear end in corners).

Yes, the dual-mount is also a sway bar. The analogy I use to explain it is the 'teeter-totter' effect. The stock single center mount spring has one pivot point in the middle. You push up on one end, the other goes down. You need an equalizer bar to help counteract that reaction. The dual-mount has two pivot points. Two teeter-totters end to end with the center ends connected with another hinge. When you push up on the outside end of one, it's other (center) end goes down, pulling the center end of the other teeter-totter down and thus raising that one's outside end an equal amount.

When I got my rear dual-mount kit from VBP they included a sway bar. I thought it odd because they say it's not needed. I went ahead and put it in, and my rear slid out a number of times. I disconnected it and had no more trouble with that.
I called VBP and she told me it should not have been included in the kit and even though I was not charged extra for it, if I wanted to return it, they would refund me the price of it. I said thanks, but it's not worth the trouble to me to return it, I'll just put it up in the garage attic with all my other leftover parts.

And as an aside, I also tried 460 coils up front, then cut them, then just bought 550s and that was best. The cut 460s--it's the same spring rate as the 550 just more coil--did not seat properly.
 
Last edited:
What I'm wondering about is a full dual mount kit, front and rear. It comes with front and rear sway bars. If the dual mount spring it's self has anti-sway characteristics are the sway bars, especially the rear, necessary? I know sway bars are not supposed to add stiffness to the suspension but IMHO they do. If only one wheel is rising or falling do to road conditions seems to me there is additional force applied to that wheel's motion. I can feel the difference in my car with the rear bar attached or disconnected.
 
Last edited:
Probably know enough about suspension technology to be dangerous. ...About the rear sway bar. I've read that Hollywood car stunt drivers will reomove the front sway bar from a car, and install a strong rear sway bar. It makes it easy to spin the car out....create dramatic spin outs for a movie. In other words, a car with just a rear sway bar will create a car with exaggerated oversteer characteristics. So....., I'm thinking that a car with a front sway bar and no rear sway bar will have a tendency to understeer. I think I'll hold up my hand when someone says, who wants understeer. My only "performance" driving will be on the freeway; overtaking, changing lanes, and then quickly steering back into my original lane. Also negotiating a freeway off ramp. What I worry about is off throttle oversteer. I want to hit the throttle, steering into another lane, steer back, and let off the throttle....I don't want to induce an off throttle oversteer. So for me I leave the rear sway bars off. When I explained my thinking to Dick Guldstrand (he was setting up my 68's suspension) he didn't disagree with me. (In all fairness, he didn't verbalize agreement). I had the front sway bar from VBP's Street and Strip set up. I think it duplicated the F41 suspension option. Guldstrand said their front sway bar was to stiff. He installed a sway bar with less diameter.
 
I would really like to see someone test this on a dual mount. Put a load on one end and see if you get any movement on the other end. That would tell you if the spring is acting as a sway bar.

I'm a rank amatuer, so this is more a question then a statement - but moving the mounts out on a rear spring would increase the effective rate of the spring - and mathmatically, it's possible to figure out how much. Putting a rear sway bar would increase that rate to the point where you'd oversteer on a scary basis because you'd have insane spring rates. It would comply vertically as long as it was doing it on both wheels, but the moment one wheel dropped the rear of the car could feasibly raise every time it hit a bump.... I'm a big fan of each part doing only their part in the suspension (and I say that tongue in cheek because I had a GM A-body where the rear sway bar also kept the axle centered) - so from my understanding, I can't see a reason to have a dual mount; if you need more spring, use coil overs. My hypothesis (gained from the Abody) is use the softest spring that will maintain ride height and acceptable travel, then control vertical motion with adjustible (or good) shocks, control its lean with sway bars...

or?
 
I have a VBP 360# plastic spring in the rear on my '72 vert, my trick is to keep the ride soft and decent, and went Bilstien shocks a few years ago to soften it up and quit bouncing over the bridges...

I have spinal compression, skull to hips....to to stay comfy is my first requirement, and somehow I can't see/understand how in hell that would happen going to a dual mount spring setup.....

In fact I wish I had a 330# spring back there.....

:clobbered:
 
I have a VBP 360# plastic spring in the rear on my '72 vert, my trick is to keep the ride soft and decent, and went Bilstien shocks a few years ago to soften it up and quit bouncing over the bridges...

I have spinal compression, skull to hips....to to stay comfy is my first requirement, and somehow I can't see/understand how in hell that would happen going to a dual mount spring setup.....

In fact I wish I had a 330# spring back there.....

:clobbered:
I started with a 330# with Bilstein Sport shocks and found it too hard for me. I changed to a 300# spring, at VBP recommendation, and it was still too hard. I went to SPAX adjustable shocks and can get a real nice ride now but too soft for spirited driving and ride height very sensitive to fuel level. My guess would be a 330# spring with adjustable shocks like the SPAX would be my best combination. I have however a complete, new, VBP full dual mount spring kit with upper and lower front control arms and all. So I'm going to try it with my SPAX shocks instead of the Bilsteins. :drink:
 
Remember too, dual mount springs have easily adjustable spring rates. I have changed mine several times. It's a heck of a lot easier than changing whole springs, as I have also done several times up front.
The problem I have run into is, while I started off just wanting a good running fairly stock car, the better I got it to run, the better I wanted it to run. A number of things I did at first I now wish I had done differently (---Brake calipers being a big one).
With 550s up front and longer spring bolts in back, I'm so low now I have to worry about speed bumps & driveways. I keep bending my headers. But it sure runs better now.....Stiffer yes, but better, oh yes!!
 
I'm with most others here. I don't think the c2/c3 needs a rear bar except in very defined circumstances. I put a 7/16" on the back of mine years ago. Made the car prone to snap-oversteer. Removed it two months later.
 
I have a VBP 360# plastic spring in the rear on my '72 vert, my trick is to keep the ride soft and decent, and went Bilstien shocks a few years ago to soften it up and quit bouncing over the bridges...

I have spinal compression, skull to hips....to to stay comfy is my first requirement, and somehow I can't see/understand how in hell that would happen going to a dual mount spring setup.....

In fact I wish I had a 330# spring back there.....

:clobbered:
I started with a 330# with Bilstein Sport shocks and found it too hard for me. I changed to a 300# spring, at VBP recommendation, and it was still too hard. I went to SPAX adjustable shocks and can get a real nice ride now but too soft for spirited driving and ride height very sensitive to fuel level. My guess would be a 330# spring with adjustable shocks like the SPAX would be my best combination. I have however a complete, new, VBP full dual mount spring kit with upper and lower front control arms and all. So I'm going to try it with my SPAX shocks instead of the Bilsteins. :drink:

UNclear to me is if you had a single/center mount spring or a dual mount....

curiosity about if the spring itself is the same or not....

I suspect NOT....

:noworry:
 
I have a VBP 360# plastic spring in the rear on my '72 vert, my trick is to keep the ride soft and decent, and went Bilstien shocks a few years ago to soften it up and quit bouncing over the bridges...

I have spinal compression, skull to hips....to to stay comfy is my first requirement, and somehow I can't see/understand how in hell that would happen going to a dual mount spring setup.....

In fact I wish I had a 330# spring back there.....

:clobbered:
I started with a 330# with Bilstein Sport shocks and found it too hard for me. I changed to a 300# spring, at VBP recommendation, and it was still too hard. I went to SPAX adjustable shocks and can get a real nice ride now but too soft for spirited driving and ride height very sensitive to fuel level. My guess would be a 330# spring with adjustable shocks like the SPAX would be my best combination. I have however a complete, new, VBP full dual mount spring kit with upper and lower front control arms and all. So I'm going to try it with my SPAX shocks instead of the Bilsteins. :drink:

UNclear to me is if you had a single/center mount spring or a dual mount....

curiosity about if the spring itself is the same or not....

I suspect NOT....

:noworry:
Single/center mount. I now have the rear dual mount on the rear only. The dual mount spring is physically different from the single/center mount. It is slightly shorter, less taper and a different shape. Kinda flat in the center instead of a smooth curve end to end.
 
I have a VBP 360# plastic spring in the rear on my '72 vert, my trick is to keep the ride soft and decent, and went Bilstien shocks a few years ago to soften it up and quit bouncing over the bridges...

I have spinal compression, skull to hips....to to stay comfy is my first requirement, and somehow I can't see/understand how in hell that would happen going to a dual mount spring setup.....

In fact I wish I had a 330# spring back there.....

:clobbered:
I started with a 330# with Bilstein Sport shocks and found it too hard for me. I changed to a 300# spring, at VBP recommendation, and it was still too hard. I went to SPAX adjustable shocks and can get a real nice ride now but too soft for spirited driving and ride height very sensitive to fuel level. My guess would be a 330# spring with adjustable shocks like the SPAX would be my best combination. I have however a complete, new, VBP full dual mount spring kit with upper and lower front control arms and all. So I'm going to try it with my SPAX shocks instead of the Bilsteins. :drink:

UNclear to me is if you had a single/center mount spring or a dual mount....

curiosity about if the spring itself is the same or not....

I suspect NOT....

:noworry:
Single/center mount. I now have the rear dual mount on the rear only. The dual mount spring is physically different from the single/center mount. It is slightly shorter, less taper and a different shape. Kinda flat in the center instead of a smooth curve end to end.

Thanks man, so I know quick and easy, as opposed to a lot of effort for the info....

:friends:
 
I have a VBP 360# plastic spring in the rear on my '72 vert, my trick is to keep the ride soft and decent, and went Bilstien shocks a few years ago to soften it up and quit bouncing over the bridges...

I have spinal compression, skull to hips....to to stay comfy is my first requirement, and somehow I can't see/understand how in hell that would happen going to a dual mount spring setup.....

In fact I wish I had a 330# spring back there.....

:clobbered:
I started with a 330# with Bilstein Sport shocks and found it too hard for me. I changed to a 300# spring, at VBP recommendation, and it was still too hard. I went to SPAX adjustable shocks and can get a real nice ride now but too soft for spirited driving and ride height very sensitive to fuel level. My guess would be a 330# spring with adjustable shocks like the SPAX would be my best combination. I have however a complete, new, VBP full dual mount spring kit with upper and lower front control arms and all. So I'm going to try it with my SPAX shocks instead of the Bilsteins. :drink:

UNclear to me is if you had a single/center mount spring or a dual mount....

curiosity about if the spring itself is the same or not....

I suspect NOT....

:noworry:
Single/center mount. I now have the rear dual mount on the rear only. The dual mount spring is physically different from the single/center mount. It is slightly shorter, less taper and a different shape. Kinda flat in the center instead of a smooth curve end to end.

Thanks man, so I know quick and easy, as opposed to a lot of effort for the info....

:friends:

Yer welcome!
:drink:
 
Last edited by a moderator:
Remember too, dual mount springs have easily adjustable spring rates. I have changed mine several times. It's a heck of a lot easier than changing whole springs, as I have also done several times up front.
The problem I have run into is, while I started off just wanting a good running fairly stock car, the better I got it to run, the better I wanted it to run. A number of things I did at first I now wish I had done differently (---Brake calipers being a big one).
With 550s up front and longer spring bolts in back, I'm so low now I have to worry about speed bumps & driveways. I keep bending my headers. But it sure runs better now.....Stiffer yes, but better, oh yes!!

:hissyfit: Oh you be loving what the idiots did here, they resurfaced a mile worth of main yellow feeder road into the development, been shitty since I been here on the last two block to bottom of the hill, but the rest was tolerable, but NO the dumb bastards redid the entire road, then proceeded to put HELLACIOUS rumble strips that are about 3" tall and 3-4 strips per batch, and 4 batches, and so it ruins every car going over it, so we have to go about 1/4 mile outta our way to avoid the road now, rendering it basically useless to everyone in the burb now.....God DAMN PC .gov, run by idiots.....

:hissyfit::surrender: tax money up in smoke for nothing, worse than nothing....
 
Top