motown 71

My was stock slowly changing 71 coupe has no sway bar in the rear.
There is a 3/4 bar up front, what size bar should go on the rear and what would I gain by the installation ?
:crazy:

NHvette

Only install the rear with a matching front. The 3/4" front is too small to
match a rear up. You'll probably want 1 1/8" up front - 5/8" in the back.
This will noticably decrease body roll, without going to harsh springs.
Do you need it ? Only YOU can answer that question .... well, do you ?
MANY (and most SB) vettes did not have a rear sway bar.

If you do put new bars in, you are likely to start driving faster around corners. :steering:


[Modified by NHvette, 5:38 PM 2/16/2004]

motown 71

Faster around corners......
Faster anything is G-O-O-D !!
Thank NH
Dave
:party:

Jay M

This is a topic of much debate!

But I was at Laguna Seca two years ago to see all the corvettes race. I looked under about ten C3s and only saw two rear sway bars. And one was on the greenwood car that had 14" tires in back. I'd so no don't use a rear sway bar

~Jay

VegasJen

i am not a believer that a street driven c-3 needs a rear sway bar. i put on mine and have since disconnected it. now, if your on a track and running slicks, that's a different story.
then again, my name isn't greenwood or guldstrand either

Cali,68,L-79

thanks you guys just made up my mind. I have a 11/8" up front and a bare 7/8" sitting ready to go in, but there are 2 kits, and one looks like I need a press so F it! Thanks saved me money/ time.

etteroc27

I used a 427 big block front roll bar on my 72 after I modified the engine. Sometime later I added a rear bar, 5/8's if I remember. The thing I noticed most was that the ride quality became much harsher, and I could not notice much of an improvement in the handling. I like handling, but I don't feel that I gained much. My car has a completely rebuilt suspension, with bilsten shocks and poly bushings. The biggest change in ride quality was the rear anti-sway bar. I feel every bump on the road now.

turtlevette

years ago i put a big hunking swaybar on the back.

I had so much oversteer i thought i was dirt tracking it.

if you put one on the back you are going to have to increase the front bar size to maintain a balanced car.

Also the rear bar limits how big a tire you can run on the rear.

Cali,68,L-79

It really made it that harsher?? Wow definetly won't do it.

Jay M

hmmm As far as I know Greenwood says YES to rear sway bars, while Guldstrand says NO. In fact Dick Guldstrand removed mine himself! It made the rear end much more predictable. No more supprise oversteer.

As he explained it to me-
As the car leans in a corner the inside wheel wants to lift up off the ground. With posi-traction when that inside wheel starts to lift up it will spin and cause the outside wheel to spin. Then there will be major oversteer!

If you have a rear sway bar that effect is made much worse. without a rear sway bar the the inside wheel gets better traction.

As far as I know this is only true of our particular suspension design. Most other cars work better with a rear sway bar including C4s and C5s.

~Jay

KenSny

A street car driven normally does not require a rear bar. If you are driving corners fast, as in road racing or autocross, you will want to neutralize the oversteer-understeer so that the front end does not plow into corners and the back end does not come around to fast. You need to be sure that the sway bars, springs, shocks, etc all work together. Don't expect to put on big bars with some soft shocks and springs and expect good results.

A lot of guys in SCCA do not even use a rear bar.

LiveandLetDrive

What matters is front to rear balance. If you establish that (perhaps a percentage of torsional stiffnesses?) you can upsize front and back in unison, and aim for a target amount of body-roll, or ride-comfort. If you are set up to be neutral, then a large bar is not going to cause excessive oversteer. This is why it's called neutral, hehe.

Basically a really stiff swaybar is undoing the benefits of independant suspension (except of course unsprung weight), and stiff springs are undoing the benefits of having springs in the first place. But body roll is also bad... figure out a solution to these conflicts and you have a comfortable to ride in world-winning race car. :lol:

-Chris

Paul L

Just a comment from research and not road experience. The pic shows a GM late C3 FE7 (7/16") rear sway bar that I have in my basement. FE7 was 1 1/8" in front and 7/16" in the rear. Aftermarket rear bars seem to be 9/16" thickness as a minimum. Why so thick I do not know but someone is outguessing GM engineers and those aftermarket bars may be the source of the above-noted problems.

flynhi

Zora and GM designed the C3 suspension in 61 and modified it as tires got better. Base suspension had considerable understeer for safety and even F41/FE7 had some understeer.

VBP sells packages that (IMHO) must be matched with good to very good tires to perform well. I ran BFG T/As with VBPs 1 1/8 and 3/4 bars and experienced pronounced oversteer. with 17" wheels and very good tires, the VBP combo feels very good.

Too much rear bar essentially converts the independent rear suspension into a solid axle.

For most street use, OE front bar and no rear bar performs very well.

Paul L

I hear you. I will probably put that sway bar on Ebay. I was thinking of putting it on my 1967 but I can't see what value would be added for my kind of driving.

motown 71

Thanks for all opinions and views, good stuff here! I'll be going as is 3/4 up front and nuttin' in the rear.

:steering:

Cali,68,L-79

Me to!!!


:yesnod: :yesnod:

Paul L

I have decided to sell that FE7 rear sway bar. See C3 Parts for Sale.

The Dude

EDIT: Nevermind.


[Modified by The Dude, 9:54 PM 2/19/2004]

Cali,68,L-79

Jack lot of experience on this thread saying NAY to the rear S.B. I'm going with their advise. plus I believe there is no way to get it on with current exhaust configuration.