How do you determine what the largest clamping shim OD you would use with a shim stack?
Very difficult question, because there is no set answer.  What type of
dampers are you using and what does the manufacturer
recommend?  Whatever that is, it's probably a bit on the safe side.

When
doing a 1-off build, I usually try to go with something kind of 'middle
of the road'.  That way if I want to change it to get a little more or a
little less overall damping, I can just change the clamp shim 1mm up or
down and have an easy, but effective, change.

I also usually end
up using a large stack of thin shims rather than a small stack of thick
shims.  That's more personal preference as far as getting the curve,
though.

What are you using, what are you using it on, and what is your overall goal?filter
It is a set on a set of motorcycle forks, but the if there is any type
of "rule" governing the largest OD using some type of formula then it
would be universal I would figure.

I am looking to increase
overall damping on a compression stack that currently uses a 9 mm
clamping shim with a 6 mm ID. I know I could stiffen up the stack by
increasing the shims, but I also know that I can do it by increasing the
clamping shim size.

I really have not played around too much
with different clamping shim OD's and would like to find out what their
effect is vs increasing the shim count.
And just looking at the stack you've laid out, I think you might have too
little low speed.  With no preload and a large step from the sealing to
the next shim, it will crack off the piston port very easily, even with 3
sealers.  Uncovering the port even 0.05mm will allow a lot of oil to
flow.  Think of what a small amount of oil the needle/seat adjuster
flows and how much it effects the damping.

With a 2 stage stack,
I've always seemed to end up with too little low speed for a certain
amount of high speed.  By the time I get the low speed where I want it,
the high speed is way too much.  I think off-road guys get it to work,
but on a track, I never really have.

My advice is to stick with a
relatively simple stack.  It's way easier to go slower with shock
changes than it is faster.  Regardless of what you end up running, keep
good notes, and let us know how it worked.

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