Fork valving

A service reference
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canyncarvr
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Fork valving

Post by canyncarvr »

Not many of youse guys fuss with this I think...but 'ya never know until you ask.

IdahoCharley?

Consider the following stack:

20 bleeder shim
24 (3)
22
20
17
15
12

Two questions.
1. Who likes bleeder stacks, who doesn't...and why or why not?

2. Who has swapped the 22/20 to give the 25s more room to flex. That would tend toward a dual stage stack..but not really...just sort'a.

Thanks!

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Post by IdahoCharley »

CC Wrote - "Two questions."
"1. Who likes bleeder stacks, who doesn't...and why or why not?"

Looks like your questioning mid-valve bleed shims. Can of worms IMO because there is no one correct answer it all depends..........

I like a predicable response from the forks when I hit something and it can be achieved with a bleed shim but is IMO somewhat dependent upon the speeds and debris that you normally encounter where you ride .

ANS - If your base valve is firm and your mid-valve is firm and of the clamp variety then a correctly sized bleeder shim in your mid-valve should help the bike settle in corners better. That would be good and thus liked if it did not introduce any other problems.

Too small or too thick of a shim allows more oil bleed prior to engagement of the following shims and can lead to harshness related to blowing through a portion of the fork travel before activation of additional shim stack. This is bad and thus not liked by me - some people may like the versatile of this set-up. (i.e. still stiff enough to jump)

IMO if your suspension is oversprung and running a clamped mid-valve (verses a spring loaded check plate or spring loaded mid-valve) then a bleeder shim may work well because the over springing of the bike tends to keep the bike up in the fork travel and the bleed valve allows it to settle for corners or when on the brakes. (Both good thus liked - like when you have bought a larger MX dirt bike for the kid (or wife) and you know they will be growing into it within a year or two (weight wise) and don't want to invest in new springs every year the kid grows.

"2. Who has swapped the 22/20 to give the 25s more room to flex. That would tend toward a dual stage stack..but not really...just sort'a. "

ANS - Don't see any 25s in your stack but flipping the 24(3) 22 20 to 24(3)20 22 will soften the mid-valve but not by much. If you want to soften it so that you will notice it pull the 22. (Normally you want the supporting shim size to be with in 4 or 5 mm diameter to get decent life out of the shim stack) I'am running forks off a 01 CR 125 on the boy's KDX and I'll look at my notes tomorrow and see what I went with - seems good to us.
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Post by canyncarvr »

Oops...I edited the 25s out of the stack config and made it 24s (cuz that's what I think they in fact are)..but did NOT change the '25' in the write-up.

In a progression of stacks from more firm to less firm, would you say a 24(3) 20 22 would be between 24(3) 22 20 and 24(3) 20 17?

Does 'not by much' mean it wouldn't be effective to any extent..or would it be a 'step' in the direction of dropping the 22?

I understand that how they ride is what works...and without specific knowledge of a fork and a rider it's all going to be an 'it depends'.

While I don't mind working on my bike..I don't plan on taking it apart every weekend for the next six months fussing with it. So, I'm looking to develop a 1/2-way reasonable approach from the beginning.

Listed in the first post is a known/used midvalve comp stack from bradx btw.


What would you estimate the effect to be of changing the existing .15s to .10s keeping the SAME shim OD configuration? Is that WAY too big a jump?

Use all the same ID? ID is a tuning tool, also, is it not? I'll probably make 'em all 8mm or whatever it is that fits. I don't recall the ID on mine..didn't write it down.

Point of THAT question is to put together an MX-Tech shim order. At $1.20 each..it adds up!

Thanks IC!

**Just ADDED 'em up. Comes to about $100!! That's a lot for a handful (a small one) of washers........
Last edited by canyncarvr on 01:22 pm Apr 29 2009, edited 1 time in total.

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Post by Indawoods »

CC... I am disappointed in you.

I was of the impression that you are the head first kinda guy. And now you go and try to save yourself frustration, money and time.

I am at a loss for words right now.... :?
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Post by canyncarvr »

I was a head first kind'a guy LAST week.

Going up a brushy trail, looking at the ground at what I thought was a converging track, SMACKED my head on a sapling leaning over the track I was riding on.

Now that's head first!

Hit hard enough to blur my vision for the rest of the day..and I got real sleepy, too! :rolleyes:

So..I changed my ways! This is the new me!

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