C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Leaf spring-composite vs. steel

Thread Tools
 
Search this Thread
 
Old 06-05-2016, 07:01 PM
  #1  
Lee Smits
2nd Gear
Thread Starter
 
Lee Smits's Avatar
 
Member Since: May 2016
Posts: 2
Received 0 Likes on 0 Posts
Default Leaf spring-composite vs. steel

Need to replace to leaf spring on my '78 soon, is there a big difference in composite over steel? Every parts supplier refers to the composite as an upgrade, just wondering what everyone's experience with composite is.
Old 06-05-2016, 07:33 PM
  #2  
DUB
Race Director
 
DUB's Avatar
 
Member Since: Apr 2009
Location: Charlotte NC
Posts: 19,294
Received 2,713 Likes on 2,321 Posts

Default

Nothing wrong with going with a new composite rear leaf spring.

There only drawbacks are HEAT and some idiot tow truck person using it to pull from with the hooks and chipping it.

The ride will improve and you can custom tailor how much spring rate you want....for what you are using your Corvette for.

They are also MUCH EASIER to install. Due to being so light.

DUB
The following users liked this post:
Lee Smits (06-05-2016)
Old 06-05-2016, 07:44 PM
  #3  
The13Bats
Race Director
 
The13Bats's Avatar
 
Member Since: Mar 2003
Location: Eustis ( Area 51 Bat Cave ) Fl
Posts: 11,608
Received 772 Likes on 645 Posts

Default

Originally Posted by DUB
Nothing wrong with going with a new composite rear leaf spring.

There only drawbacks are HEAT and some idiot tow truck person using it to pull from with the hooks and chipping it.

The ride will improve and you can custom tailor how much spring rate you want....for what you are using your Corvette for.

They are also MUCH EASIER to install. Due to being so light.

DUB
did the factory go to composite for cost or because they are better in many ways?
Did you see the picture the member posted the exhaust burnt up a composite spring?
I have them front and rear and as you know have had to have my poor car towed more than a fair share and I am always up on the tow driver where not to hang those hooks...
The following users liked this post:
Lee Smits (06-05-2016)
Old 06-06-2016, 09:03 AM
  #4  
dochorsepower
Drifting
 
dochorsepower's Avatar
 
Member Since: Sep 2010
Location: Laguna Niguel California
Posts: 1,412
Received 49 Likes on 42 Posts

Default

I've had a composite spring on mine for over 30 years, no problems. The original steel spring broke after 8 years. You will have to get different shocks to control the rebound rate. Most guys get Bilstein or Koni adjustables.
Old 06-06-2016, 10:06 AM
  #5  
Tim Ware
Instructor
 
Tim Ware's Avatar
 
Member Since: May 2016
Location: Vermont
Posts: 178
Likes: 0
Received 22 Likes on 18 Posts
Default

Dochorsepower: You bring up a good point on the need for different shocks. I'm a new owner of a 71 & have the composite spring. And I've noticed that the rebound can be pretty abrupt ( Vermont has terrible roads ). The previous owner installed new AC Delco shocks all around and probably had no knowledge of the spring's requirements.
I hope this doesn't take away from this thread, but would you explain a little more about your experience & recommendations ?
Thanks, Tim
Old 06-06-2016, 10:27 AM
  #6  
jb78L-82
Le Mans Master
 
jb78L-82's Avatar
 
Member Since: Oct 2007
Location: Rhode Island
Posts: 7,114
Received 740 Likes on 617 Posts

Default

I have had my VBP 360 mono spring on my car since 1985 (30+ years)...The composite spring is superior to steel in every way..weight, response rate, ride comfort, etc...GM has used composites on all corvettes since 1984 and it's not for cost savings..composites are superior to steel springs. You do need a quality shock to be matched with composites..no mass market shocks like Monroe, Gabriel, KYB...I have Bilstein Sports with my 360...
Old 06-06-2016, 11:02 AM
  #7  
bence13_33
Safety Car
 
bence13_33's Avatar
 
Member Since: Aug 2000
Location: Clymer PA
Posts: 3,909
Received 26 Likes on 26 Posts

Default

I really like my 420lb mono spring....if nothing else for the sheer weight of it compared to much heavier 9 leaf spring. It was already mentioned but you definitely need to keep the composite springs away from heat as much as possible.
Old 06-06-2016, 07:16 PM
  #8  
DUB
Race Director
 
DUB's Avatar
 
Member Since: Apr 2009
Location: Charlotte NC
Posts: 19,294
Received 2,713 Likes on 2,321 Posts

Default

Originally Posted by The13Bats
did the factory go to composite for cost or because they are better in many ways?

I believe it was to lighten the car...and actually you can get a higher spring rate. I do not knwo WHY GM did it...
Did you see the picture the member posted the exhaust burnt up a composite spring?

YES...I have seen it before at my shop and do not need to see a photo of that. SO...making sure your exhaust does not cook the spring is up to the person doing the job. GM did have a stove shield to aid in this issue.
I have them front and rear and as you know have had to have my poor car towed more than a fair share and I am always up on the tow driver where not to hang those hooks...
YEP...just put a good nick it it and give it time...the spring will begin to shear.

DUB
Old 06-07-2016, 04:36 PM
  #9  
Richard Daugird
Melting Slicks
 
Richard Daugird's Avatar
 
Member Since: Dec 2015
Location: Texas City, TX Texas
Posts: 3,143
Received 718 Likes on 518 Posts
Default

I have heard many times that the Bilstein Sport is recommended, as well as the HD, but no one mentions part numbers. I am having trouble finding the right one for my car, I plan to go composite as well. This will be a weekend fun street car, riads not too bad, on 50-60 series 15" wheels.

Last edited by Richard Daugird; 06-07-2016 at 04:37 PM.
Old 06-07-2016, 04:45 PM
  #10  
drwet
Melting Slicks
 
drwet's Avatar
 
Member Since: Dec 2009
Location: Thunder Bay
Posts: 3,041
Received 538 Likes on 413 Posts

Default

Switching to a composite rear spring was one of the best upgrades I have done to my '79. Ride and handling are both vastly improved. I have the Vette Brakes & Products 330 lb spring and KYB shocks. They have been on the car for about 20 years.
Old 06-08-2016, 03:35 PM
  #11  
dochorsepower
Drifting
 
dochorsepower's Avatar
 
Member Since: Sep 2010
Location: Laguna Niguel California
Posts: 1,412
Received 49 Likes on 42 Posts

Default

I have the standard spring and couldn't stand the bouncy rebound so I went with Koni adjustables set at one turn stiffer than factory medium and it feels just like I want it.
Old 06-08-2016, 04:32 PM
  #12  
Alwyn678
Team Owner
 
Alwyn678's Avatar
 
Member Since: Jun 2001
Location: Thomson Georgia
Posts: 43,095
Received 143 Likes on 126 Posts

Default

Originally Posted by jb78L-82
I have had my VBP 360 mono spring on my car since 1985 (30+ years)...The composite spring is superior to steel in every way..weight, response rate, ride comfort, etc...GM has used composites on all corvettes since 1984 and it's not for cost savings..composites are superior to steel springs. You do need a quality shock to be matched with composites..no mass market shocks like Monroe, Gabriel, KYB...I have Bilstein Sports with my 360...

I guess since Corvette switched in 84 they seemed to agree. I wonder if the agreement applies to the older corvettes as well
Old 06-08-2016, 05:46 PM
  #13  
DUB
Race Director
 
DUB's Avatar
 
Member Since: Apr 2009
Location: Charlotte NC
Posts: 19,294
Received 2,713 Likes on 2,321 Posts

Default

Actually the composite rear leaf spring was being used in 1981 on a Corvette. I believe the 1980's were still steel.

DUB
Old 06-08-2016, 07:28 PM
  #14  
jb78L-82
Le Mans Master
 
jb78L-82's Avatar
 
Member Since: Oct 2007
Location: Rhode Island
Posts: 7,114
Received 740 Likes on 617 Posts

Default

Originally Posted by DUB
Actually the composite rear leaf spring was being used in 1981 on a Corvette. I believe the 1980's were still steel.

DUB
Correct DUB! 80 C3's all had steel transverse leaf springs, base and sport suspension.

The 81/82 BASE suspension only corvettes had a composite leaf spring and the gymkhana cars had a steel leaf spring. Starting in 1984 ALL C4's had composite transverse leaf springs, front and rear, regardless of suspension specified. The 81/82 composite springs were rated at a whopping 172 lbs/in...total marshmellow versus the FE7 Gymkhana sport springs rated at 306 lbs/in.

I love my 360lb composite that replaced my 7 leaf steel gymkhana spring in 1985 (292 lbs/in in 1978). The 360 VBP composite monospring rides much smoother than the 292 steel spring. The beauty of a composite spring is that the spring rate can be MUCH higher than a steel spring with a MUCH better ride/handling, its reaction time to bumps/ road irregularities is much faster (this where the bouncy nature comes from-use a quality shock and no issues) and weighs 8 pounds versus 50 lbs for a steel spring. Yes there have been some issues with delamination of the composites but that is by no means a common occurrence-witness the forum members like me that have 30+ years using a composite. My 505 NET HP C6Z06 has no issues either with its rear composite.....

Last edited by jb78L-82; 06-08-2016 at 07:40 PM.
The following users liked this post:
DUB (06-09-2016)
Old 06-09-2016, 07:38 PM
  #15  
DUB
Race Director
 
DUB's Avatar
 
Member Since: Apr 2009
Location: Charlotte NC
Posts: 19,294
Received 2,713 Likes on 2,321 Posts

Default

Originally Posted by jb78L-82
Correct DUB! 80 C3's all had steel transverse leaf springs, base and sport suspension.

The 81/82 BASE suspension only corvettes had a composite leaf spring and the gymkhana cars had a steel leaf spring. Starting in 1984 ALL C4's had composite transverse leaf springs, front and rear, regardless of suspension specified. The 81/82 composite springs were rated at a whopping 172 lbs/in...total marshmellow versus the FE7 Gymkhana sport springs rated at 306 lbs/in.

I love my 360lb composite that replaced my 7 leaf steel gymkhana spring in 1985 (292 lbs/in in 1978). The 360 VBP composite monospring rides much smoother than the 292 steel spring. The beauty of a composite spring is that the spring rate can be MUCH higher than a steel spring with a MUCH better ride/handling, its reaction time to bumps/ road irregularities is much faster (this where the bouncy nature comes from-use a quality shock and no issues) and weighs 8 pounds versus 50 lbs for a steel spring. Yes there have been some issues with delamination of the composites but that is by no means a common occurrence-witness the forum members like me that have 30+ years using a composite. My 505 NET HP C6Z06 has no issues either with its rear composite.....
THANKS.

I am amazed on how much my brain can remember this stuff. Sometimes I fell I am correct...but there is a part of me that wonders if I am confusing it with something else due to all the years I have to deal with.

DUB
Old 06-10-2016, 07:12 PM
  #16  
BlackC3vette
Burning Brakes
 
BlackC3vette's Avatar
 
Member Since: Jan 2012
Posts: 943
Received 73 Likes on 69 Posts

Default

Originally Posted by Richard Daugird
I have heard many times that the Bilstein Sport is recommended, as well as the HD, but no one mentions part numbers. I am having trouble finding the right one for my car, I plan to go composite as well. This will be a weekend fun street car, riads not too bad, on 50-60 series 15" wheels.
Mine is an 80 and for right now, just to get this thing on the road again, I am reinstalling the original steel spring. But I did replace the old sears shocks with Bilsteins B6 - HD. I actually found them not only in stock, but a decent price and shipping on Tire Rack!

Get notified of new replies

To Leaf spring-composite vs. steel




Quick Reply: Leaf spring-composite vs. steel



All times are GMT -4. The time now is 07:32 AM.