fiberglass rear leaf spring
 

does the car ride any better with one of these? my 66 rides like a bucket of poop with the steel leaf

Put one in my 63 was a lot better

YES...they can ride much better....depending on the spring rate.

And keep in mind any excessive radiant heat from exhaust pipes can effect the composition of the spring material....so possibly wrapping up the pipe slightly before the spring area and after can aid in its life expectancy.

You can contact Gary at Vette Brakes and Products and he can explain it if you need a second source of validation.

DUB

A combination of good gas shocks that are designed to work with the composite spring can result in a better ride.:cheers: Dennis

thanks guys. it has a good set of gas shocks all the way around. i already have a slightly used fiberglass spring. i will have to give it a try

Define 'better'? A new leaf spring is better than an old and tired one too:thumbs: A correct balance between spring and dampers and car has probably more impact on 'better' than just looking for the best composite spring:hide:

I had one on a 72 coupe that I owned. Did not like it. I believe it was the 300 lb unit and it rode stiff. My 66 with the 9 leaf spring rides great. I wouldn't even think about installing a composite unit in it. JMO

:iagree:

I put one in my 63 and my 69.

Clear improvement.

I had the same thing. Very stiff ride. I took it out 5000 miles later and put a new stock spring in. Much better! The stiffer springs maybe good for racing, not so good for street use. I went for stock a spring, large sway bars, good shocks and tires. Makes for a comfortable riding street car.

I posted this is a similar thread six months ago or so, but it's still my opinion.

A monoleaf composite spring has no interleaf friction, like a multi-leaf steel spring, and requires shocks with a much higher level of damping (rebound and compression). Stock type shocks won’t do the job and you’ll have a “bounce” problem. So, without getting into spring rates and ride quality, unless you can get shocks “engineered” for a specific composite spring, I would stay away from one.

In my opinion, Chevrolet did a pretty good job engineering the 2 stage (6/3) spring in the midyear Corvette. If you’re serious about replacing a steel spring, I would give Eaton Detroit Spring a call – their springs are about as close to original as you will find.

I also wonder how much "improvement" you get with this sort of thing. I put AC Delco shocks on my 63 with the original springs and it rides wonderfully.

They didn't have the fiber glass spring back then just my opinion
my 63 handled better maybe my shocks were bad .
It felt better maybe the original was fatigued

I like Fiberglass
 

I have fiberglass rear springs on my 66 BB and 71 LT1 . I like them .

FTF, what ac delco shocks did you use? Do you have a part number? While working on the brakes, there's gonna be some scope creep. The shocks that are on now have seen better days and the bushings are shot.

What was oem on these back in the day, ac delco?

Yes. I replaced my sagging spring with a fiberglass mono leaf along with more stout shocks. I used the stock shocks at first and it bounced all over.

Mono leaf is not supposed to sag over time either.

Yes AC-Delco were originally from the factory, I replaced my Monroe Gas-Ajust with AC-Delco modern equivalents to get some judging points for having at least the correct brand and they turned out to be nice shocks... I'd have to dig through my receipts to find the actual part numbers....I think I might have just gone to NAPA and had them look them up for the 63.

Spring
 

Just to make sure you dont have other issues:
1. What cold tire pressure are you running?
2. Are your tires more than 10 years old?

Some interesting info on the subject from an online vendor that sells both steel and composite springs.

"Composite vs. Steel Rear Leaf Springs

A couple of times a week we are asked to give the plusses and minuses of composite vs. steel rear leaf springs. This is how we see it:

The TRW spring is the OEM replacement spring for the 81 and 82 Corvette. From 1963-1980, Corvettes came with steel rear leaf springs. In an effort to shave weight off the car to help with fuel economy, for the 1981 model year Chevrolet went with magnesium valve covers, a composite rear spring and a number of other weight saving substitutions. The spring change saved about 20 lbs; a huge savings for comparatively little money. To the end user, the twenty pounds is equivalent to about two and a half gallons of gas; not exactly earth shaking for the average Corvette driver.

Unfortunately the composite spring weight savings was right where the Corvette least needed to lose weight; low and behind the rear axle. The steel spring is like ballast in a racecar, right where it needs to be; low and behind the rear axle.

Composite springs don’t lose their spring rate over time. A 315 lb spring will stay 315 lbs until it breaks. Yes, that’s what sends composite springs to the dumpster; a rock in just the right place. Hit on edge by a road hazard, a composite spring will often de-laminate. It will turn a milky white at the point of injury and its service life is over. A steel spring will slowly lose its spring rate over time, but it will never break.

The softest TRW composite spring is 315 lbs. Most C2 and C3 Corvettes came with 196 lb. steel rear springs. After 20 years or so, when they are ready for replacement, their effective spring rate has eroded by as much as 40%. Replacing the original spring with a new stock steel spring makes a big difference; a 40% difference. Changing to a 315 lb spring would be a change of 270%, and you would have a completely different automobile.

The spring rate of the 78-80 OEM factory steel rear spring was 260 lbs. You can order a 315 lb spring for a 78-79, but for anything newer than that, you have to chose between 345 and 355 lbs. That’s a heavier spring rate than we run on our racecars, so you can imagine it’s not the softest ride on the planet.

One more thing that may or may not be a big deal to a street driven Corvette: The steel spring is at least somewhat progressive in its spring rate. In our custom steel springs that we use for our racecars, we individually arch every leaf to achieve an almost linier rate progression. This helps handling a lot, and we see it in our lap times. Obviously that’s not possible with a composite spring.

In summary:

Composite spring Advantages:

• Light weight
• Permanent spring rate

Disadvantages:

• Cost
• Durability
• Limited spring rate options
• Often much stiffer than stock"

Last I heard, Gabriel makes Delco shocks. I have Delco Professional on my 65, and I like them very much. Gabriel Ultra gas shocks are suppose to be the same as the Delco Professionals. Rock Auto sells both brands for a C2 at about 20 dollars a piece. :thumbs:

In a few days i will be replacing my steel with composite, how would i know what shocks to get?