Showa Forks mid valve shim stack for wood

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4/1/2019 9:59 PM

I have a Showa A-kit forks that i want to Soften for gnarly staff and wood riding
I assume, according to what I have been reading, that the mid valve is responsible for all the little rocks and roots “feel” and in general - all the high speed movements
do I guess the key is removing shims of the mid valve.
I guess it will take few tries since i have never revalved shock before but i want to get direction where to start of

So my fork is disassembled and my mid valve was taken out
Lets say, i want my fork to be 15-20% softer than now
so, is removing one big shim from each side of the mid valve will increase the flow enough?
What about the base valve, any changes are recommended there?

Thanks guys

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4/3/2019 6:38 AM

What bike do you have? Do you have your current shim stacks measured?

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4/3/2019 6:51 AM

Polishhammer wrote:

What bike do you have? Do you have your current shim stacks measured?

I have a CR125R 2007, modified for tight technical terrain
I weight 80kg without gear
Front spring is 0.46 according to RaceTech spring calculator (by putting CRF250RX 2018 as a reference with the showa 49mm)
I like stiff suspension but at the moment the compression and the rebound clickers are open and it feel little stiff
I’ve been riding like that for 60hrs ~ one year and no complaints
But it can be done better

I don’t have the current shim stack, my base valve is still with all the shims, i will check it tonight
Any way, i want to make it little more soft for the roots and the small stones

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4/3/2019 12:15 PM

Comp BV:
7 - 22mm
2 - 19mm
1 - 17mm
1 - 15mm
1 - 13mm

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4/3/2019 12:24 PM

How thick are the shims

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4/3/2019 12:36 PM

Helda wrote:

How thick are the shims

0.01mm
Can I remove 3 face shims?
There is any amount of shims i need to put so it will touch the valve?
Or it is ok its free?

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4/3/2019 12:53 PM

They will be 0.10mm, you can remove them, If you need packing shims put them under the clamping shim.

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4/3/2019 12:57 PM

Helda wrote:

They will be 0.10mm, you can remove them, If you need packing shims put them under the clamping shim.

Is it ok it is moving free?
I just removed 3 shims so now i have 9 in total and it seems they move free

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4/3/2019 1:25 PM

You are about 3 sizes too stiff on your fork spring. You should be on a .43kg at most for a CR125 at 175lbs

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4/3/2019 1:37 PM

slipdog wrote:

You are about 3 sizes too stiff on your fork spring. You should be on a .43kg at most for a CR125 at 175lbs

Thanks for the reply guys

This is the first time i am setting up my suspension myself
Cause every time i am leaving it to some local suspension guy everything still feel the same

I have just checked my left fork and the spring stamped 0.448 that means i am somewhere in the upper boundary do you think i can get along with it?
I have a rubber on the fork and it is not using the whole stroke, it leaves about 30mm but i think it is mostly because of the valving and not the spring rate

I had CRF250x 2009 stock fork with stock spring on it before and it was on the soft side for me

and as more as i read about it the more i see that my shim stack is damn too stiff
Isn’t it? 7 face shims of 20mm on the compression side of the mid valve?

Any way purchasing springs take too long, I live in Israel and everytime i buy something on Ebay it takes 2-3 weeks until i get so...

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4/3/2019 2:13 PM

Helda wrote:

They will be 0.10mm, you can remove them, If you need packing shims put them under the clamping shim.

Yotam wrote:

Is it ok it is moving free?
I just removed 3 shims so now i have 9 in total and it seems they move free

When you say moving free do you mean the piston or the shims? It's so hard to say to be honest, what was you mid valve float with it all together?

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4/3/2019 2:16 PM

Helda wrote:

They will be 0.10mm, you can remove them, If you need packing shims put them under the clamping shim.

Yotam wrote:

Is it ok it is moving free?
I just removed 3 shims so now i have 9 in total and it seems they move free

Helda wrote:

When you say moving free do you mean the piston or the shims? It's so hard to say to be honest, what was you mid valve float with it all together?

Shims move free, piston is tight
Was 12*0.1= 1.2mm
Now 9*0.1=0.9mm

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4/4/2019 3:20 PM

cut your cross bar. 49mm and twin walls will make it feel harsh.

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4/4/2019 3:24 PM

Radfonz wrote:

cut your cross bar. 49mm and twin walls will make it feel harsh.

Seriously?
I dont think it can help with suspension set up but maybe Swap my bar to non twinwall could help with vibration and staff?

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4/4/2019 3:28 PM

Yotam wrote:

Is it ok it is moving free?
I just removed 3 shims so now i have 9 in total and it seems they move free

Helda wrote:

When you say moving free do you mean the piston or the shims? It's so hard to say to be honest, what was you mid valve float with it all together?

Yotam wrote:

Shims move free, piston is tight
Was 12*0.1= 1.2mm
Now 9*0.1=0.9mm

Some mid stacks move freely on shaft or bush (float) to allow some flow before the mid valve comes into play. So now you'll get more flow but knowing how that effects the feel on the bike is what takes years of trial and error. Essentially what you have done right there is a revalve, at a basic level. Getting more flow on float doesn't automatically mean softer and plusher on rock and roots like I think your chasing. Your going to need a bigger selection of shims to change out, add in, increase in thickness etc. and time. It will be softer now though so reassemble and go out and find out how-where-why. And use red Loctite like 262 on the shim retaining nuts.
Slip has put you on the right track with getting your spring rate right first though. Get the basics right first. Play with your oil levels and clickers and I'm sure you'll get some improvement.

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4/6/2019 3:32 AM

I agree the spring rate looks stiff for you’re weight and off-road. As we get older most of us don’t to slam stuff with the front tire like we used to because it makes our wrists hurt.
If you could measure and post your stacks it would help us to get tell you what other direction to go with shims. I’m curious if there is a crossover in the base valve? If not adding one will help. Also it would work well to soften the high speed side which is the shins in the bottom or the smaller ones.

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4/6/2019 3:34 AM

Yes the crossbar on twin walls needs to go. A lot of pros cut it. Kurt caselli has his cut when he was alive and well racing. I personally would run a different bar.

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4/8/2019 12:25 PM

Ok so i will replace my bar
Thanks for the advicwhat about the spring rate?
Any recommend bar?
My preference is the 994-996 bent of renthal
Do they have one without bridge?
(I rather buy new one and sell mine than cutting the bridge)

Are you guys sure it is too stiff?
The CRF250RX is wood-machine and it weight 10kg more than my CR and it comes with .49, my weight is 85kg (need one stage stiffer spring on most of my bikes) and i have .458 on my bike
I don’t think the spring is my problem

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4/8/2019 6:27 PM

Yotam wrote:

Ok so i will replace my bar
Thanks for the advicwhat about the spring rate?
Any recommend bar?
My preference is the 994-996 bent of renthal
Do they have one without bridge?
(I rather buy new one and sell mine than cutting the bridge)

Are you guys sure it is too stiff?
The CRF250RX is wood-machine and it weight 10kg more than my CR and it comes with .49, my weight is 85kg (need one stage stiffer spring on most of my bikes) and i have .458 on my bike
I don’t think the spring is my problem

Someone with good experience has given you good advice on spring rate. I'd take it unless you know better.

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2/11/2020 6:54 AM

Polishhammer wrote:

Yes the crossbar on twin walls needs to go. A lot of pros cut it. Kurt caselli has his cut when he was alive and well racing. I personally would run a different bar.

If goin the Bar route to fix the harshness, get flex bars, I know they are pricey but make a big difference!
But personally I try to get suspension working well then add the flex bars,

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2/11/2020 7:41 PM

I'm 160lbs, and ride a YZ125. .44's springs work good for me for vet mx riding. For offroad stuff, you would tend to go softer though.

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