Shock shim question

[bte]

I decided it was time for me to revalve my shock myself (my first). I have revalve my forks may times, so I didn't think the shock would be to bad.

Everything went very well. Even easier than I thought, to get it apart. Once I had it apart I was taking notes on the shim stack and came across something I couldn't understand, so I thought I would ask the Pro's (of atleast the guys that see more shocks than me).

A little info.
04 TE250
Sachs shock.

I understand that not may people have worked with the Sachs, but maybe someone can tell me why they did this or has seen this before.
The Question:
In the rebound shim stack. I have a stack of 3 - 38 o.d. 12 i.d. shims. The 2nd shim in this stack is a 36 o.d. with another 38 o.d. 36 i.d. shim outside of the 36 o.d. shim.
So it's
(all shims are the same thickness)
38 o.d. - 12 i.d.
36 o.d. - 12 i.d. / 38 o.d.- 36 i.d.
38 o.d. - 12 i.d
It seem to me that it would be the same as 3 38 o.d. shims.

Maybe this is done alot, and I just don't know it because this is the first shock I have taken apart.

I'm sure that there is a reason it is setup like this, but what is the reason ?

Thanks for any info
brown

 

[marcusgunby]

Do you mean it has a shim thats like a band that sits around a smaller shim(36mm od)? as if so its like a pds-it preloads the shims and acts like a stiffer shim stack under small deflections, but on larger deflections its more like a normal stack.

 

[bte]

Yes!
It is somewhat like a band. The 36 o.d. sits inside the 38 o.d. shim. When put together is form (1) 38mm o.d. shim.

Thanks,
brown

 

[Jeremy Wilkey]

Its what we call a preload shim, its purpose is as Marcus pointed out. In more techincal terms it increases the load of the stack without increasing the rate of the stack..

BR,
Jer