Rear leaf spring... fiberglass?
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 3,193
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From: Pittsburgh PA
Rear leaf spring... fiberglass?
I'm thinking about upgrading to a fiberglass leaf spring. Is it worth the $260? How much does it weigh compared to a stock spring in a 79? Also, if I were to get one, which would you recommend (315, 340, 355)?
Thanks,
Jerry
Thanks,
Jerry
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: Rear leaf spring... fiberglass? (jerryjfunk)
I am also planning to do the change to a composite spring. I'm also wondering which one is the right composite spring for my setup. My front suspension features the Grand Touring 460 lbs/inch springs. I was thinking in putting a 340 lbs/inch composite spring on the rear...
I think that the important thing is that your spring has to work good with your front suspension.
:cheers:
Olivier
I think that the important thing is that your spring has to work good with your front suspension.
:cheers:
Olivier
Racer
Joined: Apr 2001
Posts: 413
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From: Bluffdale Utah
Re: Rear leaf spring... fiberglass? (jerryjfunk)
I think this is the best purchase I've ever made for my car. I went with, I think, the 360 lb spring and my car rides and corners better than ever!! I think the stack of steel leafs weighed about 55 lbs. The composite spring is about 6 lbs. Just my 2 cents.
Burning Brakes
Joined: May 2000
Posts: 765
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From: Canton GA
Re: Rear leaf spring... fiberglass? (jerryjfunk)
I'll be doing this in the fall. I don't want to go over 340lbs.
I bought a good book "How to restore and MODIFY your 68-82 corvette" by Richard newton. In it he explains that one of the biggest mistakes people make is going with too stiff a spring trying to reduce body roll. This is not the job of the spring...that's handled by the sway bars. Anyway its good reading...I'm going to go with the 340lb spring on the rear but add a sway bar since my SB car didn't come with one.
I bought a good book "How to restore and MODIFY your 68-82 corvette" by Richard newton. In it he explains that one of the biggest mistakes people make is going with too stiff a spring trying to reduce body roll. This is not the job of the spring...that's handled by the sway bars. Anyway its good reading...I'm going to go with the 340lb spring on the rear but add a sway bar since my SB car didn't come with one.
Le Mans Master
Joined: Apr 2000
Posts: 5,202
Likes: 10
From: cincinnati ohio
St. Jude Donor '09
Re: Rear leaf spring... fiberglass? (jerryjfunk)
Yoy won't regret switching to a glass spring, ride quality is improved 10 fold.
As for weight savings they are super light...maybe 6-8 lbs? :cheers:
As for weight savings they are super light...maybe 6-8 lbs? :cheers:
Drifting
Joined: Mar 2001
Posts: 1,514
Likes: 1
Re: Rear leaf spring... fiberglass? (yellow 72)
I agree with the above, composite spring works well. Some things to watch for is enough clearance from the exhaust obviously they aren't as heat tolerant as the steel. I have a TRW 355# spring and will probably go 340 when I replace it.
Scott
Scott
Le Mans Master
Joined: Aug 2000
Posts: 6,273
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From: Austin TX
Re: Rear leaf spring... fiberglass? (jerryjfunk)
GrandSportC3 has it right - Balance is the key. Richard Newton also has it right - for street driven Vettes, go with softer springs and beefier bars - beefier up to a point.
After experimenting with several different combos, I landed on the following:
front: VB transverse on softest setting (OE 285# coils would be fine here),
1 1/8" stabar, Bilstein Sport shocks, poly bushings, HD idler arm, BFG 245/15/60 T/As on 1908 alum wheels.
Rear: TRW 315 composite spring, 5/8" stabar, Bilstein Sport shocks, poly bushings, Smart Strut bracket, long spring bolts, BFG 255/15/60 T/As on 1980 Alum Wheels
very good overall performance and ride quality. Tires are an excellent value at about $80.
My experience was that rear bars larger than 5/8" induce significant oversteer and undesired dizziness due to spins. Remember, Zora only used rear bars on Big Blocks to induce some oversteer to counteract the massive understeer due to the heavier front end of a BB.
After experimenting with several different combos, I landed on the following:
front: VB transverse on softest setting (OE 285# coils would be fine here),
1 1/8" stabar, Bilstein Sport shocks, poly bushings, HD idler arm, BFG 245/15/60 T/As on 1908 alum wheels.
Rear: TRW 315 composite spring, 5/8" stabar, Bilstein Sport shocks, poly bushings, Smart Strut bracket, long spring bolts, BFG 255/15/60 T/As on 1980 Alum Wheels
very good overall performance and ride quality. Tires are an excellent value at about $80.
My experience was that rear bars larger than 5/8" induce significant oversteer and undesired dizziness due to spins. Remember, Zora only used rear bars on Big Blocks to induce some oversteer to counteract the massive understeer due to the heavier front end of a BB.
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Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 3,193
Likes: 0
From: Pittsburgh PA
Re: Rear leaf spring... fiberglass? (Scott78)
Thanks for the input. I had no idea they only weighed 8 lbs! Has anyone found a better price than $260? Also... how much does a stock leaf spring go for these days? I'll probably take mine apart, sand them to the metal and paint. Maybe someone will give me $200 on ebay :lol:
I remember a thread about shocks a couple weeks ago... was it determined that KYB are better than most for the money? If so, I'm going to get them... is 4 for $130 about right?
Thanks,
Jerry
I remember a thread about shocks a couple weeks ago... was it determined that KYB are better than most for the money? If so, I'm going to get them... is 4 for $130 about right?
Thanks,
Jerry
Le Mans Master
Joined: Aug 2000
Posts: 6,273
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From: Austin TX
Re: Rear leaf spring... fiberglass? (jerryjfunk)
The rebound characteristics of fiberglass or composite springs are quite different than steel springs. After trying Koni, KYB, GM, Tokico, Carerra and Monroe, I strongly advise you to spend the extra $ and get Bilstein Sports from VB. They are properly valved for composite springs, have long service life and can be rebuilt for half the cost of new.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: Rear leaf spring... fiberglass? (flynhi)
flynhi, I have heard that bilsteins are supposed to be better than the KYB I have and have been happy with for 6 years now, on my VB plastic spring '72 rear...thing is, what are the differances you noticed??? and yes 130 bux for 4 KYB shocks is a decent price, compared to others....I have KYB on all 4 corners and paid that 6 years ago...been happy, but wonder what I did miss about the bilsteins....except the price maybe....
GENE :D :D :D :cool:
GENE :D :D :D :cool:
Le Mans Master
Joined: Aug 2000
Posts: 6,273
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From: Austin TX
Re: Rear leaf spring... fiberglass? (mrvette)
My experience with KYB was that they were a lot stiffer and tended to bounce more that the Bilsteins. Paul Lisinsky at VB has worked with Bilstein to understand the correct jounce and rebound rates optimal for fiberglass springs. This work has occurred in the past few years - since you bought your KYBs.
When I switched from KYBs to Konis, my ride quality improved considerably - much less boounce and less road surface feel coming up through my butt.
A couple of years later, I switched from Delco HDs to Bilstein Sports and the bounce and porpoise I was experiencing disappeared.
As you know, GM has used Bilsteins on Vettes with composite springs since 84 - must be a reason.
When I switched from KYBs to Konis, my ride quality improved considerably - much less boounce and less road surface feel coming up through my butt.
A couple of years later, I switched from Delco HDs to Bilstein Sports and the bounce and porpoise I was experiencing disappeared.
As you know, GM has used Bilsteins on Vettes with composite springs since 84 - must be a reason.
Race Director
Joined: Apr 1999
Posts: 11,520
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From: CORVETTE 77 385 C.I. TEXAS
Re: Rear leaf spring... fiberglass? (flynhi)
It is imperative to have a balanced setup esp. if you drive hard- Rec.!
For stock springs you want about 300 rear. Have never used. You should consider the entire setup so some like Will (flynhi) have mentioned a bounce problem w/ softer springs.
Some say about FE-7- What Suspension.
Have FE-7 & VB rear. No bounce problem ever w/ Koni adj. or Delco Performer.
:cool:
For stock springs you want about 300 rear. Have never used. You should consider the entire setup so some like Will (flynhi) have mentioned a bounce problem w/ softer springs.
Some say about FE-7- What Suspension.
Have FE-7 & VB rear. No bounce problem ever w/ Koni adj. or Delco Performer.
:cool:
Le Mans Master
Joined: Oct 2001
Posts: 5,943
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From: Wildwood IL
Re: Rear leaf spring... fiberglass? (jerryjfunk)
.. how much does a stock leaf spring go for these days? Thanks,Jerry
Forget stock... buy composit, you'll be glad you did. I didn't.. and I'm sorry :cry :cry :cry :cry :D
Safety Car
Joined: Apr 2001
Posts: 3,574
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From: Middleboro/Boston MA
Re: Rear leaf spring... fiberglass? (flynhi)
After experimenting with several different combos, I landed on the following:
Rear: TRW 315 composite spring .
Rear: TRW 315 composite spring .
a 315lb some day. :smash:
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 3,193
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From: Pittsburgh PA
Re: Rear leaf spring... fiberglass? (flynhi)
"GM has used Bilsteins on Vettes with composite springs since 84 - must be a reason."
Good point, I agree. :yesnod: How much are Blisteins, and where's the best place to get them?
Thanks,
Jerry
Good point, I agree. :yesnod: How much are Blisteins, and where's the best place to get them?
Thanks,
Jerry
Racer
Joined: Mar 2002
Posts: 499
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From: honolulu HI
Re: Rear leaf spring... fiberglass? (jerryjfunk)
VB sells the bilistiens for about $70 a piece..the kyb's are only $30 a piece..it says that kyb's are now set special for composite rear springs..are these the kyb shocks that people have tried and are not happy with or are these now set up different?
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 3,193
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From: Pittsburgh PA
Re: Rear leaf spring... fiberglass? (razz1980)
"are these the kyb shocks that people have tried and are not happy with or are these now set up different?"
I'd also like to know the answer to that... it would be a shame to spend that much more on shocks that would be almost the same as KYB's.
ALSO... what modifications are required to use a C4 or C5 rear spring in a C3?
Thanks,
Jerry
I'd also like to know the answer to that... it would be a shame to spend that much more on shocks that would be almost the same as KYB's.
ALSO... what modifications are required to use a C4 or C5 rear spring in a C3?
Thanks,
Jerry
Drifting
Joined: Feb 2002
Posts: 1,987
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From: Manchester, Dead Center in the Middle of TN 25 miles to Jack Daniels,10 miles to Geo Dickle, and .8 mile from the Liquor Store at I-24 Exit 114
St. Jude Donor '05
Re: Rear leaf spring... fiberglass? (jerryjfunk)
Jerry there are two KYB shocks in the VBP catalog. I was advisded by Paul that I had the wrong ones on my '80. The new KYB for fiberglass springs is the GR-2. The original KYB is for the steel spring and works well with it.
I purchased the std. KYB's and later changed to the fiberglass spring ,then came the bounce. I am currently going to the blueprinted VanSteel Offset TA Asm.'s and will change to the Sport Bilstein shocks at that time. JIM
I purchased the std. KYB's and later changed to the fiberglass spring ,then came the bounce. I am currently going to the blueprinted VanSteel Offset TA Asm.'s and will change to the Sport Bilstein shocks at that time. JIM
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