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  #11  
Old 4 Weeks Ago
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Quote:
Originally Posted by Marty MOOSE View Post
The cross over from rebound adjustment to comp changes was larger than the tuner has seen on other shocks.
MM
Mr Moose,

I'm not seeing anything unusual on my graph. You can see quiet a large change to the rebound curve (bottom half of the graph) and yet the compression (top half) hasn't changed much.
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  #12  
Old 4 Weeks Ago
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Graph makes sense. I did 2 slow laps on the weekend. It did nothing weird and felt quite good on a sandy whooped out track. 108mm sag on the rear. Also watched a fast expert rider on my bike as well. The shock was following the ground well, but seemed a little soft for the whoops he was in. Prob could have speed up the reb a touch but not enough hrs on it yet to make changes
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  #13  
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Marty MOOSE Marty MOOSE is offline
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Quote:
Originally Posted by dwb79 View Post
Mr Moose,

I'm not seeing anything unusual on my graph. You can see quiet a large change to the rebound curve (bottom half of the graph) and yet the compression (top half) hasn't changed much.
Can only report what we saw! The only other change we made was the KYB piston which had a radically different shim stack to what I thought would work.
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  #14  
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Originally Posted by dwb79 View Post
So the general consensus is that the shock is pretty good and I agree, especially compared to the forks.

I think the biggest issue with the shock is that it is lacking low speed rebound control. This is pretty common for Sach shocks. There is a decent improvement in traction to be had here. The trouble is that the shock already has a reasonable amount of high speed rebound damping and adjusting the clicker is only going to increase this to a undesirable level.

The attached screenshot shows two dyno runs. The red graph is with stock clicker settings. The black graph is with the rebound adjuster screwed in significantly.

The black arrow shows the changes in low speed rebound and the red arrow shows changes in high speed rebound.

My ideal damping curve would be the low speed from running the rebound clicker in and the high speed from running the rebound clicker out. Or in other words, the black graph at the black arrow and the red graph at the red arrow. Make sense?

So its time for a revalve.

How far is significantly?

At what point do you typically start to see cross talk between the comp and rebound circuits?

I know on many shocks I've tinkered with as you come towards 0 on the rebound the comp side all but hydraulically locks itself up. Definite cross talk. Without a dyno and back to back runs and data hard to see where those changes start to make considerable differences though.
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  #15  
Old 3 Weeks Ago
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Quote:
Originally Posted by Jakobi View Post
How far is significantly?
10 clicks in
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  #16  
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Quote:
Originally Posted by Jakobi View Post
At what point do you typically start to see cross talk between the comp and rebound circuits?
I've attached a screenshot of a live test.

After each cycle of the shock, I unscrewed the rebound clicker one click, starting from zero (full clockwise) and working out to 30 clicks.

You can see that every clicker reduced both the compression and the rebound damping. So, crosstalk is happening all the time. You will find this to be true for nearly all shocks without a shaft jet or RSV.

I believe that crosstalk will continue to cause a change in compression damping right up to the point that the compression adjuster starts to produce more damping than the rebound clicker. Given the compression adjuster sees a fraction of the oil volume compared to the rebound clicker (14.9% in this case), we will never see an absence of crosstalk within the normal working range of most rebound clickers.
Attached Images
File Type: jpg Rebound sweep.jpg (110.9 KB, 12 views)
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  #17  
Old 3 Weeks Ago
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Quote:
Originally Posted by Jakobi View Post
I know on many shocks I've tinkered with as you come towards 0 on the rebound the comp side all but hydraulically locks itself up. Definite cross talk.
In the above graph, you can see that with the rebound clicker at zero, it takes 40kg (half an average persons weight) to compress the shock at 9mm/s.

Quote:
Originally Posted by Jakobi View Post
Without a dyno and back to back runs and data hard to see where those changes start to make considerable differences though.
I think the "considerable differences" are when the clicker change, and in this case crosstalk, puts the damping numbers outside the comfort zone. This is dependent on the original damping forces and the rebound clicker design.

Great questions Jakobi
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  #18  
Old 3 Weeks Ago
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Quote:
Originally Posted by dwb79 View Post
In the above graph, you can see that with the rebound clicker at zero, it takes 40kg (half an average persons weight) to compress the shock at 9mm/s.



I think the "considerable differences" are when the clicker change, and in this case crosstalk, puts the damping numbers outside the comfort zone. This is dependent on the original damping forces and the rebound clicker design.

Great questions Jakobi
Bloody good answer too Dave!
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