Rear spring
Thread Starter
Safety Car
Joined: Aug 2001
Posts: 3,681
Likes: 200
From: Waterford Mi
Rear spring
My composite spring has started to come apart. I don't know how long it has been on the car but it was there when I bought it 14 years ago so I can't complain.
What size should I replace it with, the 300# or the 330# from VBP.
I don't know what is on there.
What size should I replace it with, the 300# or the 330# from VBP.
I don't know what is on there.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
I would go with at least the 330 pound spring. They are not exact poundage either. When you get it look at the numbers and it will tell you exactly what it is rated at. I have seen a 330 pound spring be anywhere from 315 to 350. Ask what they have when ordering. They should be able to get exactly what you want.
Team Owner
Joined: Aug 1999
Posts: 42,487
Likes: 47
SPARTAN
CI 3-4-5-6-8-9-10 Vet
CI-9 AutoX Winner
CI-3 Go Kart Champ
St. Jude '03-'04-'05-'06-'07-'08-'09-'10-'11
Is it a VBP spring? If you're happy with how it's riding, you could always send the spring back to them and have them measure it. I believe they'll measure a spring to get close to 330, 340 or whatever you actually have.
Thread Starter
Safety Car
Joined: Aug 2001
Posts: 3,681
Likes: 200
From: Waterford Mi
Thanks for the reply. Just a question for curiosity sake, how does the ride of the composite spring compare to the original metal spring? Not that I would go back but my car has had this spring since before I got it.
Team Owner
Joined: Aug 1999
Posts: 42,487
Likes: 47
SPARTAN
CI 3-4-5-6-8-9-10 Vet
CI-9 AutoX Winner
CI-3 Go Kart Champ
St. Jude '03-'04-'05-'06-'07-'08-'09-'10-'11
But, friction = damping. That steel spring doesn't need quite as much force in the shocks to damp out ride motions because the friction helps. So if you take dampers designed for a steel spring and put them on with a glass spring, it'll be more bouncy. That really doesn't matter since there aren't people out there tuning shocks for specific spring rates and types.
Racer
Joined: May 2005
Posts: 308
Likes: 10
From: Dirty Jerzey
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Burning Brakes
Joined: Feb 2007
Posts: 779
Likes: 0
From: San Bruno California
I have a 69 vert and installed the VBP #330 spring with the Bilstien sport shock. The car seems to be somewhat springy to me and on a big bump or dip, it bottoms out. Depending on the size of the bump/dip. Last ride I went on the car bottomed out hard. Wrote about it on the forum and other members who installed the VBP # 330 said the same thing, it was kind of springy and bottomed out if they hit something big. But on the smooth open road, it felt good. As you'll see, every member has different experences with their own vette. Look up on the search and look up monoleaf spring. I called up Pattie at VBP and their going to let me exchange it for the # 360 or work out the stiffness with the tech guy. VBP, good customer service. I've only had the spring for a short time. Just my thought on the subject. Hope it helps.
Tony
Tony
Pro
Joined: Apr 2006
Posts: 647
Likes: 22
From: Norwalk CT and Boynton Beach FL
Go with the 360 spring and the Bilstein shocks. I installed the 330 last fall and the car bottoms out --- so now I have the car riding a little high in the rear. I'll probably put in Bilstein rear shocks this summer to help solve the problem. The 330's are just too soft for any kind of bumps in the road and if you're riding on smooth highway, the you won't feel any difference between the 330 or 360. Go with 360's in the rear and 550 in the front if you're doing front springs
Team Owner
Joined: Aug 1999
Posts: 42,487
Likes: 47
SPARTAN
CI 3-4-5-6-8-9-10 Vet
CI-9 AutoX Winner
CI-3 Go Kart Champ
St. Jude '03-'04-'05-'06-'07-'08-'09-'10-'11
The difference between the 330 spring and the 360 spring should be minimal in terms of bottoming out. Assuming a jounce travel of about 3 inches, there's a difference in spring load per corner of 3 x (360-330) = 90 pounds. That's not much of a difference in load.
If I was doing the suspension tuning on a C3, that spring rate difference would be used as a means of balancing out the pitch motions of the car and not for loads management (and I'd realy want an in-between rate to work with, too). The loads management would be done through damper valving and jounce bumper tuning. Since the C3 has more of a bump-stop than a real jounce bumper, it would pretty much all have to be done through the dampers.
If I was doing the suspension tuning on a C3, that spring rate difference would be used as a means of balancing out the pitch motions of the car and not for loads management (and I'd realy want an in-between rate to work with, too). The loads management would be done through damper valving and jounce bumper tuning. Since the C3 has more of a bump-stop than a real jounce bumper, it would pretty much all have to be done through the dampers.
Racer
Joined: Jan 2006
Posts: 382
Likes: 24
From: Uxbridge Ontario
I just installed a TRW composite rear spring 315 lb as I have a stock small block. It works much better then the 20 year old steel spring, it has a much less harsher ride. The car now is much more pleasureable to drive. Make sure that if you change to a composite spring that it works best with gas shocks. I used KYB's. It truly is one of those changes that makes a big difference to the ride quality. Also you just dropped some 40 lbs of steel mass.
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
When you call for a new spring... make sure you know which bolts are currently holding your spring in. There are two types of kits... OEM bolts/hardware, and non-OEM.
With the non-OEM, the kit comes with thread inserts and the bolt size is reduced. The width of the spring is different at the differential mounting point.
If you don't get a spring to match your current configuration, the new spring may not mount right.
You need to determine this before you make the call.
With the non-OEM, the kit comes with thread inserts and the bolt size is reduced. The width of the spring is different at the differential mounting point.
If you don't get a spring to match your current configuration, the new spring may not mount right.
You need to determine this before you make the call.
Burning Brakes
Joined: Aug 2006
Posts: 1,155
Likes: 0
From: San Diego California
I have a 69 vert and installed the VBP #330 spring with the Bilstien sport shock. The car seems to be somewhat springy to me and on a big bump or dip, it bottoms out. Depending on the size of the bump/dip. Last ride I went on the car bottomed out hard. Wrote about it on the forum and other members who installed the VBP # 330 said the same thing, it was kind of springy and bottomed out if they hit something big. But on the smooth open road, it felt good. As you'll see, every member has different experences with their own vette. Look up on the search and look up monoleaf spring. I called up Pattie at VBP and their going to let me exchange it for the # 360 or work out the stiffness with the tech guy. VBP, good customer service. I've only had the spring for a short time. Just my thought on the subject. Hope it helps.
Tony
Tony
