I have a 1980. I recently replaced my old leaf spring and shocks with a Composite Monospring and Bilstein Gas Shocks. I was looking for a good comfortable solid ride. I got anything but. As I am driving and hit a bump the rear end bounces easily up and down like a car with poor shocks. When I stand beside the car and push down to determine bounce as you usually do to test shocks, the front end is solid, but I can easily get the back bouncing. Is this the way it should be? Did I do something wrong on installation? :seeya

 

I bought shocks that were recommended for use with the monospring. I don't have a problem with bouncing, but I understand that using the wrong shocks will cause "Porposing" (bouncing up and down). I think I used KYB's, but it's been a while so I'd have to check to be sure.

 

Mine does not have this problem either. Maybe shocks??

 

What is the brand and psi rating of the spring? Many of the forum members have found the Bilsteins to be the best shock to use with composite springs and some claim that the TRW design is less bouncy than the ones sold by VB&P. :confused: The Bilsteins sold by VB&P are specially valved for composites. I take that to mean that the average Bilsteins do not work as well.
I recently installed a composite 355 psi (TRW design) and I'm very satisfied with it. It has turned out to be one of the best upgrades to date. Huge ride improvement over the worn out 9-leaf that it replaced. It is a little bouncy but not too bad. One of my rear shocks is shot and I will be replacing all of them soon with a set of used but fresh shocks that I bought from a forum member.

 

I have a TRW 355# spring and KYB shocks. No bouncing, when time comes to replace it I might go for the 340# TRW spring instead.

Scott

 

I can tell you why it's happening. The composits spring lacks the friction that comes from the leafs rubbing against each other. That leve of friction provides damping.

With the composite spring, that damping is gone and if your shocks don't have the proper level of low to mid-speed damping, then you're going to get that bouncing. So the "problem" is incorrectly matched shocks and spring. Which shocks to use? Not sure, take some of the advice in this thread perhaps.

Dave

 

Thanks, it sounds like a concensus, mismatch of spring and shocks. I will have to check to see just which spring and which Bilstein shocks I have and make whatever changes are necessary. Right now I feel like I am going down the road on a ball. :seeya

 

Paul Lisinsky at VB will tell you that 80% of C3 ride quality is due to the rear spring.
Miker is right about the TRW being less bouncy than the VB spring. I have tried two different TRWs and three VBs and the VBs are considerable more bouncy. I don't know that either is better or worse - they're just different and require different shocks to ride properly. Look at the photos of the two and you'll get a clue. The TRW is wide at the ends and tapers down at the center somewhat similar to a C4/C5 spring. The VB is a uniform cross section. Somehow the TRW cross section provides more internal damping than the VB.
ddcart is right about the damping of steel springs. That's why Dick Guldstrand only uses steel. He says the C2/3 suspension was designed for steel and that the damping from a steel spring is necessary for it to function properly. Without the internal damping of the steel spring, the shock must provide much more damping to avoid bouncing.
I settled on the TRW 315 for street use and it's great.
I had the same bouncing and porposing problem with my TRW 315/VB front transverse setup and changed to Bilstein Sport shocks which solved it. Call VB and talk to Paul Lisinsky about shocks for these springs- no one else! He will get you squared away...


[Modified by flynhi, 9:16 AM 7/27/2002]


[Modified by flynhi, 9:23 AM 7/27/2002]