1978 Rear Spring Change
Thread Starter
Heel & Toe
Joined: Aug 2014
Posts: 16
Likes: 0
From: Clarence New York
1978 Rear Spring Change
My 7-leaf steel spring is in need of replacement with the back end of the car sitting too low and ride a bit rough. I'm thinking of a TRW composite mono leaf spring as a replacement. Wondering which is the better option - the 340 lbs or 355 lbs? I'm also expecting this exercise is going to lead to new shocks. On a budget so trying to upgrade in phases here. Thx.
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
My 7-leaf steel spring is in need of replacement with the back end of the car sitting too low and ride a bit rough. I'm thinking of a TRW composite mono leaf spring as a replacement. Wondering which is the better option - the 340 lbs or 355 lbs? I'm also expecting this exercise is going to lead to new shocks. On a budget so trying to upgrade in phases here. Thx.
I have a complete VBP Street and slalom kit on my 78 with no problems with ride height.
Team Owner
Joined: May 2001
Posts: 87,357
Likes: 1,592
From: Western NY
Before deciding on the brand of the mono leaf check out the possible problems with ride height. There are a few reports of some units providing a very high ride height. The most common unit without reported problems are from VBP. There may be others but check this out before your final purchase.
I have a complete VBP Street and slalom kit on my 78 with no problems with ride height.
I have a complete VBP Street and slalom kit on my 78 with no problems with ride height.
Le Mans Master
Joined: Oct 2007
Posts: 7,451
Likes: 974
From: RI, Now Franklin/Nashville TN
The 360 VBP composite is the replacement for the gymkhana 7 leaf spring...7 leaf steel spring is the sport suspension spring, 9 leaf for the base suspension cars. I have had my VBP 360 composite on my 78 since 1986 and the car came with the gymkhana suspension...I love mine with Bilstein Sports in the rear and Bilstein HD's in front with my 550 coils. The car is firm but not harsh and handles and rides so much better then the OEM steel spring.
Team Owner
Joined: May 2001
Posts: 87,357
Likes: 1,592
From: Western NY
Back in the mid-90s, I "went through" the suspension of the '79 coupe that my wife owned at the time (bought new). I installed a VB&P spring, and as you said, it totally transformed the ride. It went from riding like a buckboard, to actually riding like a car!
Thread Starter
Heel & Toe
Joined: Aug 2014
Posts: 16
Likes: 0
From: Clarence New York
Thx for responses so far. It seems that the VB&P composite is getting the most hits. Decision will be 330lb vs 360 lbs then. Did the spring require the longer 8" bolts or the standard 6.5"?
Team Owner
Joined: May 2001
Posts: 87,357
Likes: 1,592
From: Western NY
IIRC, I used the standard length, but since I did the job about 20 years ago, don't quote me on it. However, my suggestion would be to contact VB&P directly, and talk to their tech line. They'll ask you about the particulars of your car, and recommend a spring rate based on that.
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Instructor
Joined: Dec 2003
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From: Blythewood S.C.
St. Jude Donor '14
My 7-leaf steel spring is in need of replacement with the back end of the car sitting too low and ride a bit rough. I'm thinking of a TRW composite mono leaf spring as a replacement. Wondering which is the better option - the 340 lbs or 355 lbs? I'm also expecting this exercise is going to lead to new shocks. On a budget so trying to upgrade in phases here. Thx.
Melting Slicks
Joined: Jun 2003
Posts: 2,802
Likes: 241
From: Niles, MI
Melting Slicks
Joined: Jun 2003
Posts: 2,802
Likes: 241
From: Niles, MI
I think you may be referring to the toe steer problem which is inherent in the C3 rear suspension. The spring will have no effect on that other than the proper ride height minimizes the problem. Inboard halfshaft u-joint should be 1/2" higher than outboard per John Greenwood's recommendation in the VIP series of articles.
Racer
Joined: Feb 2009
Posts: 390
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From: Louisiana