Sidecar

Member
Jun 16, 2004
4
0
Hi all,

I have read allot of threads forks and shock's ect. Passive Valve , Active Valve and CV's on some models.
I am curious if Tuners look at the front and rear in similarities. (As far as the workings)
The rear shock Shaft piston assembly is so similar to the Mid in a fork, and we know they are the active valving.
So could we say that the Compression Adjuster in a shock as being the passive valving, just like the base valve on a fork.
I read allot on these threads, and most individuals spend more time on revalving the passive side of the forks then the active side. ( I said most )
So this brings me to my question. Why don't we here of Tuners or individual's who revalve there shock's talk on revalving the comp adjuster on a shock. Sounds to me like it would be passive valving just like the forks. The reason I say this is, they are both controlling the displace volume of oil caused by the entrance of the shaft's
Maybe I am way off here ,but it makes sense to me. Correct me if I am wrong here.
maybe some of you can make more sense of the workings of the shock.
If they are similar then why don't we here to much on revalving the comp adjuster's on the shock ? any thoughts ? :worship:
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
I think the main difference is the shock comp adjuster affects a smaller operating range(speeds) than a fork adjuster.

I think technically you are correct but the shock operation is different than a fork, the active side of a fork has a bleed(midvalve lift) and this is different from a shock that has the shim tightly clamped to the piston face.

Some tuners do modify the comp adjusters on a shock but only certain ones come to mind, the pds of the ktm and i think the 04 KXF was one that was played with by a tuner who was on the boards.
 

Sidecar

Member
Jun 16, 2004
4
0
Thanks Marcus

But isn't there a bleed in the reb curcuit on a jap shock.. and wouldn't the comp adjuster be some what position sensitive, do to the further the shaft moves into the body the more fluid is moved through the adjuster?
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
Yes there is a bleed in the reb but that doesnt really compare to the lift on the midvalve.

As for position sensititive -not totally sure really , as the linkage speeds up shaft movement deep into the travel,so to some extent i guess it is , but not like a pds on the ktm. However most people think of the compression being speed sensitive only.

Dont forget as well the shock has a bladder inflated to over 150psi-this makes it different again to a fork.

Im guessing if the fork passive side was harder to access it wouldnt be played with as much, but then that suggests people should work on the shock adjusters as they are easy to get to, again i think its down to the fact that the comp adjuster will not alter the shock feel much.Where the shock comp stack will have a massive change on feel.

On forks i think also its due to the fact older forks(pre 95) didnt have a active stack.
 

Sidecar

Member
Jun 16, 2004
4
0
Thanks Marcus once again
I think there is more of a position sensitive than we give credit to, as far as where we are into the stroke. I agree the valving is speed sensitive do to velosity of the displaced oil, but if the shaft moves X amount oil regardless of the speed it is still desplacing the same amount correct? so now this would be a 50/50 relationship as far as position sensitive and speed sensitive. I just feel I am missing some thing here, between in the coralation between the too. ( that being speed sensitive and position sensitive)

As far as the bladder is concerned, I look at it as the same as the forks air spring. Kind of the same princeable but applied in a different manner.

I am not here to dispute anyones knowledge . But I am trying to understand the differences of what I believe is or what might be happening ( from my point of view)
 

shockdoc

Member
May 3, 2001
327
0
i have been trying different valve stacks along with different spring rates in both the showa & kyb comp adjusters for some time now with nice results.

doc
 

Sidecar

Member
Jun 16, 2004
4
0
Thanks Marcus and Doc
By your post Doc I must be some what on the right track in my way of thinking. As far as the valving in the comp adjuster I am a little nieve on this, as I have never seen one apart. Are they a diggressive stack, as far as the build. You talk of this spring, how does this spring effect the aduster or the funtion of this , If you don't mind sharing.
I just like to play around with stuff and try to figure out what might be going on.
I had a friend tell me about this site and have been hooked. I have been sitting back and reading . I must add from some of the past threads that I have read there are some quite smart people on here.
Forgive me if I ask to many questions that might not be on track of the norm
:worship:
 
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