Coil-Over tuning, springs and valving

[Jeffh555]

I was watching Lite Brite's bomber car shock tuning video. The tuner talks about how important and difficult it is to dial in the rebound with on live axle cars. What options are there when you already have put in a .008 stack and you need an even lighter stack?

Smaller clamp shim, if it exists. Limitation is often the piston post diameter. More likely on FOX (1/2" Post), less likely on SAW (9/16" post) and pretty unlikely on King (5/8" post). I think Bilstein is a 12mm post, but I've never worked on them. This all assumes a 2.5 shock, I think 2.0 is the same.

 

[TTMotorsports]

I have ran a Spring on the rebound valving stack so it keeps closed when on compression but opens to free flow for coilover when you have a bypass to tune/control the suspension. I also have done a fllutter stack BUT when you do that with thin shims you run the risk of breaking the shims.

 

[JBT]

I have a friend that works at Ohlins suspension and he tested my SAW shocks on their shock dyno. His conclusion was that even with .008 valving they're pretty "stiff" on rebound when used in a 1 to 1 motion ratio. He was also wondering why FOX, king and SAW doesn't offer 0.004 and .006 shims.

 

[Jeffh555]

FOX has .004 and .006 shims.

.004 shims are sketchy, I've seen too many break, I avoid them.

 

[DesertCJ]

I have a friend that works at Ohlins suspension and he tested my SAW shocks on their shock dyno. His conclusion was that even with .008 valving they're pretty "stiff" on rebound when used in a 1 to 1 motion ratio. He was also wondering why FOX, king and SAW doesn't offer 0.004 and .006 shims.

Because even if they don't break in one direction, they can get sucked into the ports they're blocking for the compression stack to work.