kx fork shim stack configuration

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KDXsg
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kx fork shim stack configuration

Post by KDXsg »

Hi, i have recently reconfigure my 05kx125 BV shim stack. I have done a 2 stage stack to soften up the fork and to reduce low and high speed harsness.
low speed stack : 24mm, 24mm and 14mm
high speed stack : 22mm, 20mm, 18mm, 16mm, 14mm, 12mm and 11.

my doubt is will my stack configuration too weak? i have removed 5 x24mm of shim in each fork but have yet to test things out. any opinion and expericence to share? thanks.
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Tedh98
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Post by Tedh98 »

I don't know enough about suspensions to be able to look at a stack and tell how it is going to perform, so I can't help you there.

But I have been told by others that have a lot of suspension experience that the .15 shims in your HS stack are way too stiff for forks. I've ordered some .1 shims to replace those .15's. The stack I'll be testing soon has almost the same LS as factory, but the HS will be much softer. We'll see how that goes.

It sounds like you've already made this change. If the bike is ready to ride, you should go ahead and test it out. At least you'll know how that stack feels and will be better able to determine what the next step(s) will be.
KDXsg
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Post by KDXsg »

Hi, thanks for the insight. do let me know of the result for the .1mm shim and your configuration. i have tested the fork action last night and it is still too stiff for my weight. i am 65kg without gear. till then, do update on your ride report. thanks.
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Post by KDXsg »

Hi Tedh98, any update on your ride with the shim stack?
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Post by Tedh98 »

Here is a very small ride report:

http://kdxrider.net/forums/viewtopic.ph ... highlight=

I've only gone riding once since then and that was with my 8 year old daughter. While she was riding around on the pee wee track, I was off to the side riding over and hitting some logs at different speeds. I was happy with those results, but I really need to go out for a good ride to really test it out.
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Post by KDXsg »

Hi Ted, can you do a stack senario for me using the shim restacker program? or you think I should get one for myself? sound cool to be able to configure shim stack without actually doing it on the fork. thanks.
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Post by Tedh98 »

Sure, give me the stack.

I think the basic program is either $30 or $35. If you think you'll be doing a lot of testing or making changes, it is well worth the money.
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Post by KDXsg »

I am 65kg without gear. About 75kg with gear. riding condition mainly some rocky rooty terrain. some open flat sandy trail with lots of those corners.
2005 KX 125 48mmUSD
my current stack is a 2 stage. 24, 24, 14, 22, 20, 18, 16, 14, 12, 11

after testing, i still find my low speed and high speed over rocky terrain harsh. the fork refuse to soak up enough of the impact. thanks for any finding.
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Post by Tedh98 »

Your 24's and 14 are .1 and everything else except the 11 is a .15, correct?

US stacks are often times different.
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Post by KDXsg »

I measured them. yes, as what you mentioned. thanks.
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Post by Tedh98 »

I've got two views, each comparing your stack to the factory stack (I'll list the factory stack at the bottom, the US version may be different than what you started with).

The first graph is set at a harder impact, your stack is in yellow and is softer than factory.
Image

The 2nd graph is at a lower impact and shows in more detail the transition from low speed to high speed.
Image

I've tested some stacks that look similar to yours and wasn't happy. Rocks and roots were still rough and I bottomed out was too easily. In doing some reading, I came to the conclusion that my low speed was set so soft that the forks were riding too low. That would cause them to be harsh and bottom out on jumps and g-outs.

On my blog I've got a page of my ongoing experiences with revalving my forks. Near the end I've got graphs of my current set-up to compare to what I've listed for yours.

Disclaimer - my only experience with suspension tuning has been with my bike, internet research and my own trial and error. Put another way, I'm really not qualified to give tuning advice.

If you are up to experimenting, I would disable the bladders and with your stack I would try beefing up the low speed and softening the high speed. Don't forget to test different air gaps. I always bring a syringe and extra fork oil. I start with the biggest air gap and then add oil through the bleed hole to test different air gaps while I'm out riding.




Here is the factory US stack that was on my bike.
7 - 24.1
1 - 14.1
1 - 12.1
1 - 24.1
1 - 22.15
1 - 20.15
1 - 18.15
1 - 16.15
1 - 14.15
1 - 11.25
KDXsg
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Post by KDXsg »

Many thanks Ted for your time. i try to play with the air gap and preload. indeed true that my stack is soft that the bike actually sag lower. that cause lowwer ride height and was hash at the mid stroke.
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