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Discussion Starter · #1 · (Edited)
This post is one in a series of twelve posts depcting the build of my Hollowpoint MkIII.
Link to MkIII / Speedhub bike build post.

I put this post together while building my Iron Horse MkIII to demonstrate just how simple it is to change the air chamber volume on Cane Creek AD-series shocks, including the AD-12, AD-10 and AD-8.

Although servicing the AD-12 is a simple proposition, requiring nothing more than a pin spanner and a hooked tool, I recommend downloading the service instructions from Cane Creek's website, and having a replacement seal kit on hand. The seal kit is cheap insurance (less than $15) incase you damage one, and comes with a handy adapter that will make reassembly easier.

The AD shocks have three groves in the main chamber in which the retaining ring can sit. The retaining ring supports the volume plate, which determines the air chamber's volume. Greater volume (furthest in) gives the most linear travel. Less volume (closer to the lip) gives greater bottom-out protection.



Begin by completely depressurizing the shock.

Open it by unscrewing the lock ring. Use your hands and a rag, but no tools.



Use a spanner wrench to unscrew the piston from the shaft. If you need greater leverage, place the end of the shock in a vice, or use the shank of a screwdriver through the eyelets as a lever.



Removing the piston will reveal the compression & rebound rod. Remove these together by pulling straight out using your fingers.



The plate nestled in the shock is the volume plate. Insert a hooked tool or an 'L' bend allen wrench through the center, and work it out of its seat. The plate will want to come out crooked if you pull in only one location, so work your tool around to different positions to keep it level. If it gets cockeyed, simply press on it to get it flat again.



Removing the volume plate reveals the plate retaining ring and the three grooved position.



Use your fingernails and hooked tool to get ahold of the retaining ring and remove it from the shock. Be careful not to scratch the air chamber surface with the tool.



Replace the retaining ring in the desired position.

Before re-installing the volume plate, attach the black rebound/compression ramp (indicated) to the end of the rebound/compression rod and insert into the bottom of the shock. The ramped surfaces should face the bottoms of the rebound and compression adjustment screws.



Wipe everything with a clean rag and grease using Slick Honey. Assembly is the reverse of disassembly. Once assembled, pressurize to 300 psi and do a leak check in a sink full of water.


 

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I dig trails!
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Nice write up Nate!

Just to add. The LBS may be the best source of a proper sized spanner, I checked all the tool stores and came up empty. Then found one later at the LBS. I used very pointy needle nose pliers in their open position as a spanner. (use a spanner if possible)

I had a tough time the the volume plate but with patience it popped out.

These shocks are great for tearing apart. A few minute job! You inspired me to use one on my HollowPoint and haven't been disapointed. Very active shock. Thanks!

One question, I have some Mantou Prep M fork/shock grease, would it work ok as a substitute for the slick honey?

Mr. P
 

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Discussion Starter · #3 ·
Mr.P said:
The LBS may be the best source of a proper sized spanner, I checked all the tool stores and came up empty. Then found one later at the LBS.

I had a tough time the the volume plate but with patience it popped out.

These shocks are great for tearing apart. A few minute job! You inspired me to use one on my HollowPoint and haven't been disapointed. Very active shock. Thanks!

One question, I have some Mantou Prep M fork/shock grease, would it work ok as a substitute for the slick honey?
They're not as popular as they used to be, but you're right -- most bike shops should still have them.

The volume plate gets tricky if it turns sideways just a little bit, but patience and persistance pays off. Once I got a feel for it, it now just takes a few seconds to pop out.

The ease of servicability is one of the reasons I keep going back to the Cane Creek shocks. Of course it helps that they work well, they're reliable, and have a great range of adjustability.

The newer Prep M lubricant made by Motorex (gold colored) is remarkably similar to Slick Honey and is probably an effective substitute. The older Prep M made by Maxima (green color) is too runny and may even clog the air ports. The back of the tube says which version you've got.
 

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I dig trails!
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Speedub.Nate said:
The newer Prep M lubricant made by Motorex (gold colored) is remarkably similar to Slick Honey and is probably an effective substitute. The older Prep M made by Maxima (green color) is too runny and may even clog the air ports. The back of the tube says which version you've got.
Thanks, I have the Motorex version and will give that a try. You the man.

Mr. P
 

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Awesome post Nate! Thanks a lot. I didn't know how to get the piston off (the Canecreek manual isn't clear), and I didn't want to start forcing things, but your description showed me it just unscrews. Awesome, thanks.

Wanted to run this by you too. My AD-12 doesn't lose pressure or anything, but what happens is:
When I it goes through a lot of travel, it'll actually stay in a compressed state, then slowly rebound up to its original position. As if it looses 1/2 its preset pressure and gradually fills back up. It does this regardless of the rebound setting.
I cleaned, inspected the seal, and regreased it. It still does the same thing. My guess is that pressure is leaking past the "volume adjustment plate" then slowly leaking back into the main chamber.
I just want to have an idea what the problem is before I rebuild it. I too am one of those guys that like to know whats going on inside....
Whats your take on it?
Thanks again for this great post on the rebuild.
Brian.
 

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Discussion Starter · #6 ·
BigBri said:
When I it goes through a lot of travel, it'll actually stay in a compressed state, then slowly rebound up to its original position. As if it looses 1/2 its preset pressure and gradually fills back up.
I'm trying to visualize this and I don't believe this is where a leak is occuring.

If air got behind the volume plate, I believe it would equalize with the main chamber pressure (if not immediately, then after repeated deep compressions) and would never be able to return the main chamber to full pressure. Further, I think it would leak through the adjustment screws or the mounting eyelet.

I think it's more likely the tip of your rebound rod is wedged into the valve screw, or this opening is somehow otherwise plugged up.

Nevertheless, a good cleaning and a rebuild definitely can't hurt. You don't need the seal kit right away, although it does come with a handy reassembly adapter that'll let you easily slide the two halves of the shock back together without slicing any O-rings.
 

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I had a similar set of problems on an AD-12 that i was rebuilding today.

It could be the compression bits are assembled out of sequence. I did that on the first rebuild and the shock behaved in that manner. Took a long time to return to full length, never seemed to work right. Put the bits back together in the correct order (reread the directions) and the problem went away only to discover another one.

The other issue i was having was a slow and steady lose of air out the adjuster screws and mounting eyelet. That was the caused by the volume adjuster plate not being fully seated. I used the handle of a socket wrench to gently tap it all the way down into position. Both of my issues have gone away and life is good again.

When in doubt, call Cane Creek. Talked to a rep within minutes of calling on a friday afternoon, explained my problem with air loss and got the solution to it right away. Great service and very friendly.
 

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Discussion Starter · #8 ·
bbbr said:
I had a similar set of problems on an AD-12 that i was rebuilding today...

When in doubt, call Cane Creek. Talked to a rep within minutes of calling on a friday afternoon, explained my problem with air lose and got the solution to it right away. Great service and very friendly.
That's great -- and exactly the point I try to make as to why I like these shocks so much. Try that with just about anything else out there!

I'll have an interesting dilemma in the next week or so... I'm building up an Azure for my wife, and fitting an AD-12 to it.

In the past, with all of my bikes, I've spent a decent amount of time tuning the ride quality to my liking, what with all the volume, pressure, and damping adjustments.

But my wife isn't quite the tinkerer that am, nor does she know (or care) what each of these adjustments does. I'm not sure what to expect as we get her cockpit dialed in and tune the suspension the first couple rides.

"I think you've got too much bottom-out, hon!" SMACK!
 

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Great timing BBBR!
I got the problem with the rebound fixed. Yup, that was the problem, the compression shim and cylinder were reversed. Good call. I figured that out last weekend but then it leaked like crazy:( So yesterday I was going through it carefully, cleaning and lubing, when I just happened to check my email and... saw your post about the volume plate not being fully seated:idea: So on reassembly on made sure it was tapped down, and voila! No more leak!

Perfect timing on the email! Thanks dude, you saved me bunch more frustration. Id'a been ticked if I'd have replaced the seals and it still leaked:eek: I have new seals inbound, but I think its good, I'll have a set in reserve.

Thanks again guys, ya' hooked me!
B.
 

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Crank monkey
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Volume plate won't come out!!!

Hey, I have an AD-5 on my GF Sugar+ that's started making a clunking noise when it tops out. I tried varying air pressure (between 130 and 220 psi - Fisher recommends 25-35psi below rider weight - I weigh 215lbs). Higher pressures tend to clunk more on smooth terrain and over every root.
I checked all the mounting bolts, rebuilt the shock twice now, re-lubed, etc with no success, and I thought I'd try adjusting the volume plate and playing with those settings a bit. I don't usually have a problem with bottoming the shock.

Anyhow, I'm getting to the point here eventually. I followed the instructions in the post and referred to CC's service instructions, and I can't get the volume plate out. I tried using an L-shaped allen wrench, and I pulled so hard I started to mark up the edges of the hole in the centre of the volume plate. I worked all the way around, so it didn't get wedged in on an angle, and pushed it back flat each time it looked like it was going to get stuck on an angle.
So, 2 questions:
1. Did I miss anything on getting the volume plate out, or do I just need to pull harder?
2. Any suggestions on the clunking noise?

I reassemled and it seems to work just fine, except for the clunk. My next step is to call CC and ask them. However, there are lots of CC gurus here, so I thought I'd try you guys first.

PS, Awesome post as usual, Nate.
 

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Discussion Starter · #11 ·
There is nothing that can be holding the plate in there other than old grease and time. I haven't run into this problem myself, so this is a role of the dice: With a full rebuild kit at the ready, try soaking the volume plate in a light solvent (mineral spirits ok, perhaps even WD40, but NO Simple Green). I don't expect that would have any effect on the seals, but I'm not 100% positive, so I'd change 'em just to play it safe.

As you describe it, the "clunk" is probably the sound from the shock topping out due to you running higher pressures. I always recommend discarding the manufacturer's recommended pressures, unless they are absolutely specific to a particular frame/shock combination.

Instead, set by sag. On a Sugar, you're looking for around 25%. Then if you find you are blowing through too much travel (frequently bottoming), decrease the air chamber volume. This will give you a more supple ride over the smaller stuff, and ramp up at the end of the stroke, where increasing air pressure will give you a harsher ride all around.
 

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Crank monkey
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Ok

Thanks, Nate.

I'm not sure why the plate is so hard to pull out - I'll try again this weekend.

As for pressures, I've generally run the shock depending on the conditions - if I'm just riding to work on asphalt, I pump it up a bit to reduce bob. When I'm on the trails, I reduce it a bit. Otherwise I find it tends to kick me off the seat when I'm going over a log, rock, etc. That's one of the reasons why I want to move the volume plate - to give it a little more plush feel. Even if it starts to bottom on me, I figure I can just pump in a bit more air. Anyway, your original post is what got me thinking about it some more. I guess a little knowledge can be dangerous, eh?

Thanks for the suggestion - I'll let you know what happens.
 

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Wow, thats awesome how you can literaly tear down the shock and service everything yourself.

I'm going to be getting a Trance soon, I sonder what kind of differences I would see swapping the Float-R out for a AD12 or Cloud 9.
 

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about damping...

Another question for you Nate...
The shock is working great now. New seals, and Slick Honey. I'm looking for a little more low speed compression damping though. I switched to the large chamber, which seems to give a little more damping throughout the travel. The rebound adjustment is fine.
I've been in the shock but can't quite visualize how the low speed damping works, with the compression shim and compression cylinder.

Is it the four holes around the perimeter of the compression cylinder that control the low speed damping, while the shim is for the high speed? To increase low speed damping, would I need to reduce the area of those cutouts in the cylinder?
Any ideas on how I might go about doing that?
I know these are some unusual questions but if you have any tips I'd appreciate it!
Thanks again, Brian.
 

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Discussion Starter · #15 ·
You've almost got to have the shock disassembled in front of you to visualize this, but here's what's going on (as best I am able to disect).

Only the compression shim and compression cylinder are responsible for compression damping. Obviously, the tighter the shim is pressed up against the cylinder, the slower air will bleed through.

However, my impression is that volume setting has an affect on damping. A larger chamber (which is the chamber the air bleeds into from the main chamber during compression) results in a lower ramp-up, i.e. flatter pressure spike, so air will flow more easily (less damping) towards the end of the stroke.

The four holes you refer to (drilled into the inside end of the piston shaft) feed the negative air spring.

The negative air spring exists in the small space between the outside of the piston shaft, and the inside of the main cylinder.

As the shock compresses, the large white plastic "seal bushing" (as shown in photos #2 & #4 in my original post), slides back to reveal the four holes. Air bleeds in to feed this growing gap between the seal bushing and the piston.

As the shock rebounds, this air is bled back through the four holes into the volume chamber, until about 12mm of piston are left to retract. At that point, the white seal bushing covers the four bleed holes, and whatever air is stuck between the seal bushing and the piston head is trapped and acts as a negative air cushion to prevent a clunky top out.

To answer your question, other than finding a slightly thicker compression shim (Cane Creek lists only one part number), I'm not sure you have any other options to slow this any further.
 

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Wow, you seem to have figured out the workings of this shock. Thanks for all the info.

I was thinking that mine was a little under-damped, but paid close attention on a ride yesterday, and worked on my settings, and I think that my adjustment range is sufficient. I currently have the compression damping at about 3/4ths, and rebound at about 1/4th or a little less, and it seems to work pretty well. I think I'll end up sticking near these settings.

I had no idea what was going on with the negative air spring and bleed holes. Thanks for taking the time to explain the how this all works.
Brian.
 

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Speedub.Nate said:
The four holes you refer to (drilled into the inside end of the piston shaft) feed the negative air spring.
The negative air spring exists in the small space between the outside of the piston shaft, and the inside of the main cylinder.
imho that space is a variable positive volume.
if you pay attention you'll notice that after 12mm AD becomes suddenly softer: air is flowing through 4 holes into the added volume. imho that's why AD is so linear.
 

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Speedub.Nate said:
To answer your question, other than finding a slightly thicker compression shim (Cane Creek lists only one part number), I'm not sure you have any other options to slow this any further.
Try using two shims to make up the extra thickness, rather than just getting one thicker one. That should work, right Nate?
 

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Discussion Starter · #19 ·
AndrewTO said:
Try using two shims to make up the extra thickness, rather than just getting one thicker one. That should work, right Nate?
I dunno. The shim sort of fits on the end of the compression rod. I'm not sure the lip it sits on is deep enough for two shims. Anyone else care to check that out?
 

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Discussion Starter · #20 ·
30x26 said:
imho that space is a variable positive volume.
if you pay attention you'll notice that after 12mm AD becomes suddenly softer: air is flowing through 4 holes into the added volume. imho that's why AD is so linear.
It may just be symmantics.

I based my negative spring theory partly on this statement in the AD-12 instructions:

"It may be difficult to compress the shock the first time since the negative air spring chamber has not been charged. It is charged when the shock is compressed about 1/2 inch (13 mm). Once it is filled the shock will function normally."

In the zero to 12mm range of compression, this gap operates just like a negative spring should: It provides a spring force that acts to compress the shock, opposing the main chamber force to extend it. Obviously, compared to the main chamber, this volume is small, and gets smaller as the shock extends -- but the pressure spike must be substantial as compression nears zero millimeters.

I'm guessing that those four holes, being rather small, provide some slight amount of damping (both rebound and compression). You are correct that, in the 13mm through fully compressed range, this negative chamber "connects" to the volume chamber, and therefore becomes an extension of it -- contributing to the shock's linear stroke.

But I still see a HUGE difference in stroke quality (ramp-up vs. linear) by playing with the volume plate settings, which leads me to believe the extra volume added by the negative chamber is of minor consequence overall.
 
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