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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