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No Fear
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Discussion Starter · #1 ·
A friend of mine needed a DHX for his Stinky . I couldn’t find a Stinky size DHX for him over here . Those who know me know why !!

But I found a 9.5” DHX 4.0 for him from a Glory Dh frame. I Managed to resize it .

But want to know the mechanical faults it may cause.
I opened the Air cap also the bleeding port on the IFP ( only Fox DHX’s have this port) Or at least I havnt saw any on others ! Then pushed the shaft an inch in. and let fluid come out .

So now I had a Shock with 8.5” eye to eye and no air in the fluid system also the IFP position wasn’t changed . But its shaft was an inch in . That means When ( on the Stinky frame ) fully extended it was an inch through its travel ‘had some fluid behind the damper assembly .
I know it wouldnt bottom on that frame as its original travel is 3.35 “ and the Stinky’s own has 2.5” so my one inch shortening would be fulfilled by the extra travel.

Any other faults that I may havnt thought of ?
 

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Has it stayed at that length when a spring was installed? It seems like once there's the rebounding force applied from a spring, the fluid behind the piston would still go through the rebound valving anyhow, and then the resulting motion would cause the IFP to displace in towards the body to compensate, effectively increasing the IFP depth.
 

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Could be a cool idea. I'd like to see how this works out. One thing I would hope to not happen is sucking in of air through the IFP into the damper due to the negative pressure at topout (or hypertopout).

I thought possibly about a spacer or a negative spring or combo of both under the piston, but one of the issues here is the Al piston rod that can easily be damaged. Perhaps a combo of both where the spring is attached to a spacer sleeve to protect the piston rod would work, with only a slight bit of the spring sticking up on either end to minimize harshness.
 

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Either I didnt get your mod completely or your mod is way off:
1. by shortening the shaft (or at least the travelable way of the shaft) you are making a 8.5" shock with 2.5" stroke
2. your shock shaft wil expand to the complete length (when ridden) and as soon as the ifp is bottoming air will get inside the dampener through the shaft seal resulting in mazocchi style squeezing and the need to rebuild the complete assembly.

the only way to archive what you are looking for is a precise shortening of the shock body (truing) and using a shorter shaft and rebound needle.
spacers on the shaft dont do the job as there is a rebond port about 0.25" about the piston
that gets closed by the shock-shaft-bushing when extending to full stoke. This way the slow speed rebound is closed and only the high speed rebound is active (thats why your shock isnt topping out with a loud "clonk" even if you preload your spring for 2-3 full turns.

I hope you get the point of what I am trying to say as my english isnt very good.
If you dont understand why your mod doesnt work dont hesitate to ask. I will try to describe the system as "english" as possible.

CW
 

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No Fear
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Discussion Starter · #7 ·
Yup o know what you are talking about . But the shock i built dont have any negative pressure even when fully extended under the Stinky's rockers . As i bled it in that position ( eye to eye exactly as the Stinky's size) . I took it out and it keeps ist 8.5" size when its free !

I set the spring to fully open unpreloded there's no force to extend it.
 

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I see what you're saying, that the spring is placed reflecting the new stroke, but I think under rebound, you will have some hyperextension, even a small amount. The key here is if this is going to suck air in from the pressurized IFP chamber. I would love to hear how this works on the trail, so keep us posted.
 

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This will absolutely not work in any way.

There is no way you could displace fluid out of the damper through the bleed hole in the IFP and have the shock stay in that length. The shock requires a specific oil volume and gas volume. By doing what you did, as soon as you put the spring on and let the shock attempt to extend to the full length, the IFP will bottom out on the Boost Valve causing all sorts of problems including the shaft topping hard against the seal housing and the shock separating from itself. Riding it in this condition will cause damage to the shock and possible harm to you or your friend.

Bottom line. In doing this, the shock will now have to go through a complete dis-assembly and reassembly.

Darren
 
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