Andreani Advanced Cartridge kit

[howlinhoss]

I finally got the kit on Friday and took it apart. 
1. The basic components (comp piston)
 

 
2. Rebound piston
 

 
3. Preload cap mechanism
 

 
4. Max preload is 10mm (between numbers 3 and 4)
 

 
5. Needle taper comparison between theirs and mine
 

 
6. Valve assembly comparison theirs vs mine (Showa)
 

 
7. Cartridge tube (OD=25.15mm, 1") clearance is >1mm all around vis-a-vis in this case SV650 upper tube
 

 
8. stroke limiting bumpers vs ID of cartridge tube
 

 
9. Same as seen thru oil flow holes
 

 
10. Relative length of cartridge tube vs mine (Showa)
 

 
11. Compressing spring (how much?!?!?) to connect fork cap
 

So what are your thoughts on the kit? Well designed?

[pattonme]

12. compression stroke as limited by top-side bumpers
 

 
13. compression stroke as limited by banging into bottom base' "shaft" protrusion
 

[pattonme]

Ok, now for some commentary. Please don't take my criticism below as trying to sh*t on a competing offering in a crass bid to win more business. It's not. I think the points are well justified and warrant a fix from the manufacturer. The kit is a pretty good effort and at the special promotional combo-price well worth it, even if it does need some remediation by the customer or the installer.
 
I will address things in order of the pictures referenced by number.
 
 
[HASH]1) Nice bit of kit and has all the standard parts one expects of a cartridge system. The 3 black pieces are plastic and are used as spacers to limit the stroke of the valve rod. Not pictured (you can see it under the '7' on pic [HASH]11) is a fat o-ring which is their solution to a top-out bumper. It's decently squishy but I think it's a poor choice and unnecessary shortcut when a real top out spring is only a couple bucks and could be used simply by replacing one of the 3 plastic bits.
 
The pistons have a 2:1 bias which is pretty common. Some of Kayaba's I've seen have a 3:1 bias. But recent examples from Traxxion Dynamics and Racetech show no or slight bias (compression), or 2:1 for the rebound piston. The pistons used here are identical, just flipped around to keep the active valving on the smaller orifice.
 
The valving was 18-0.1 x3, 16-0.15, 14-0.15. They placed the orifices slightly more outboard which meant using 18mm shims to cover all of the lip (instead of industry "standard" 17mm, even though they'd work here too). Yes, they are fractionally more rigid than 17's but I haven't run it thru ReStackor. Remember this one valve is responsible for all of compression damping since the other one does rebound only. By comparison, I use a shim stack that is more than double the shim count and has preload which makes it stiffer still. Plus I have 2 such valves working in tandem. Furthermore my valving (and any other system using bottom-mounted comp valves) only acts on ~35% of the oil being displaced per unit of stroke. This one sees 100% of displacement.
 
Effectively they are trying to cram 3x as much oil thru the orifice than it is traditionally subjected. That explains the very light valving. But like we found with the silly-small orifices in the FZ07 damper rods (5.5mm dia), given a big enough bump (aka demand for flow), you can induce harshness (temporary hydrolock) if the orifice is too small.
 
Anyone want to calculate the area of the 3 small holes in this valve? It's roughly 2.5*3*pi(3/2)^2=53mm^2. The area for the OEM damper rod is 4*pi(5.5/2)^2=95mm^2.
 
Hold on, we have to compare relative displacements.
 
When we move a 41mm fork 10mm, on the FZ07 damper rod system it displaces 3000*pi mm^3, of which 1/3 goes thru the 95mm^2 worth of holes while the rest bleeds up into the rebound chamber. In this cartridge system we are putting the same amount of fluid: 10mm*pi*(20/2)^2=1000*pi mm^3 thru a valve area of only 53mm^2.
 
If people experience problems with sharp/big bumps in an otherwise low-restriction damper rod system, how does having only HALF the valve area not present a problem? So when dealing with a sufficiently hard/sharp bump, the compression leg can move only as fast as the oil viscosity and valve area permit, even if there were no shims at all. 
 
I don't know where that point is in terms of shaft speed (cm/second) and maybe hitting a 1" bump at 40mph is below this valve's threshold. I'll need to spend some time with ReStackor.
 
But in my book this is a BIG oops!
 
What Andreani should have done was made a mirror-image piston and put the compression valving on the big side of that 2:1 bias. Then there would be 106mm^2 of valve area which still might not be sufficient to handle extreme cases (>1.5" bump at 60mph), but the inflection point would have moved dramatically farther up the velocity:area:viscosity curve.
 
If you want, you can flip the valve around and it should work just as long as you're careful to keep the spring cap, spring, and pop-off shim centered. It normally sits in a recess which by flipping the piston over you don't have anymore. As to what the new valving should be, I don't know.
 
 
Q: But wouldn't that unduly restrict the rebound stroke on the compression leg and induce torque moments into the axle and triple tree just like above?
 
A: Not at all. Because the Rebound leg is also gating flow thru the smaller set of orifices and reducing it further still with it's shim stack which is pretty darn stiff. You want the rebound stroke to be much slower than the compression stroke anyway. And by using the same size orifices for the rebound stroke in both legs, the forces are considerably more balanced.
 
 
 
[HASH]2) The rebound shims are 18-0.2 x2, 16-0.2, 14-0.2. That's approximately the same as 32 shims of 0.1mm thickness. My normal setup for 0.95kg/mm springs is equiv to 31. But mine only see 66% of the oil vs Andreani's which again sees 100%.
 
I believe that makes Andreani's over damped by 10 worth of 0.1mm shims. But I may be wrong.
 
Given that rebound damping needs to be pretty stout even under a 2-pair setup, and this is trying to do it all with just one valve, I think it would have been far smarter to equip both sides with rebound valving. Thicker shims make tuning more difficult. A stack of 0.1 and 0.15 would allow considerable flexibility. It's not like there isn't plenty of space to hold the shims... [Edit: can't put a stiff rebound stack on the Comp valve or it will cavitate]
 
 
More to come but I gotta get @howlinhoss  forks done by the time he comes home tomorrow from the beach.

[pattonme]

Back to [HASH]1)
That large'ish silver part in the top right corner? It screws into the bottom of the cartridge tube and your fork bolt screws into that. It's Locktite'd in with something that's pretty strong. You'll have to get it good and sizzle your hand hot for the Locktite to let go. Oh and it's straight out of the Kayaba parts bin. Not even modified. I have a bin full of them that came from ZX6F bikes.
 
So if you wanted to turn the 2-piston setup into a traditional 4, just unscrew the spring seat (I'll put money it's the same 22x1.0mm thread) and flip the tube end for end. Add the extra piston, shims, and wala!
 

[pattonme]

[HASH]3, 4) Fork caps
You can only add 10mm of preload for a total of 20. If you need more, you should change out springs, though you could try to add some washers below the spring (more on that later).
 
This is a fixed-height cap. In traditional caps when you add preload the part you're twisting decends into the fork cap body. If you slack off, it gets longer. If you have low-mounted handlebars this could be a problem either because you can't get a tool in there or there just isn't enough vertical space. AFAIK the FZ07 doesn't have either problem. But a fixed-height cap is "cool".
 
Except for one thing. The traditional caps have little grooves in them so you can "add a line of preload" and visually see it. While Andreani's also have 2 such grooves, they don't move so there is absolutely no visual cue as to how much preload is in there and how much did I just add/subtract? Basically unless you tape your settings to your triple-clamp, you have to wind it all the way out, and then count revolutions in. To be fair, some of the more modern sportbike caps have the exact same problem. but remember, they look cool.
 
In [HASH]3 you can see the key that rides in the slot to transmit the twisting motion of the golden piece to the black colored part which then in turn rides in the threads joining the black and gun-metal parts. They have nicely formed threads (bless you CNC) but I sure wouldn't want to make something this involved by hand.

[pattonme]

[HASH]5) Needle taper
Here we can see the Andreani has a very, very minute taper to it's needle. Now I'll grant you mine's (gold, short needle) pretty aggressive but the idea was that a 1/4 or 1/2 turn should make a noticeable difference. It also closely mimics the Showa needles.
 
Andreani's is so shallow it's great if you're trying for that minute amount of adjustment I guess. 4 full turns (what you set it to when installing the caps) and you've barely changed the orifice size. I think this was a poor choice on their part since the user (not generally a suspension expert who can feel a pea under a mattress at 80mph) will wonder why he can't feel any changes despite several turns one way or the other. It also pre-supposes the setup they started with is bang on.
 
I might be good, but I'm not that good. But if you're going to spend hours and hours on a shock dyno to get it just so, well great.

[pattonme]

[HASH]7) Fit into the upper tube
Like I said that's an SV650 Gen1 tube (I'll re-take with FZ07 tube in the morning). Andreani is using a 25.15mm tube (probably the standard slightly oversized bar stock made by the foundries) whereas the entire motorcycle industry uses 24mm and has for 20 years. Ok, so it's 0.5mm on a side fatter but every little bit is making the path the oil must take from under the tube, past the side of the cartridge and into the spring area that much smaller. At some point it becomes too restrictive. Is that the case here? I very much doubt it, but I would have to test it wet.
 
To me, the presence of this passage way is part of the damping circuit, even if it's pretty light. If you gut the upper fork tube, then absolutely everything depends on the compression valve to keep things in check. I'm not confident they've got that figured out.
 
That may be why their instructions call for removing the entire innards of the tube as that will provide an over-abundance of flow. But if you're going to do that, then by gorge, why aren't they selling a 25 or 30mm system to FZ07/SV650 etc. owners?! That would be a KILLER and unique offering and wouldn't cost anything extra. Doing all these major mods just to put in a 20mm system, is disappointing.
 
This is what a gutted tube looks like. It's a ninja 300's 37mm tube with a 20mm cartridge system that I did for @howlinhoss.
 

[pattonme]

[HASH]8-10) Stroke-limiter spacers
 
I'll talk more about stroke-limits later, but I took these pics to show just how massive these are (whopping d=18.5mm!!) relative to the ID of the cartridge tube (d=20mm). Since they are so fat, they displace a TON of oil which means there is a lot of high speed fluid movement in and out of the 4 holes. The rod itself is 10mm which is very common. But I would have cut these spacers down to 14mm, maybe 15mm diameter to minimize their impact and, let the valving do it's job with as little interference. It's not just the spacers, the base of the valve is also 18.5mm in diameter. Everything I've ever seen has been under 16mm.
 
Recall that on compression, all that fluid has to get thru the valve orifice and then "squeeze" past these spacers with not even 1mm of gap between them and the wall. Yeah... the cross section of the area behind the piston is a mere 47mm^2 vs the needed 53. It's dramatically worse for the rebound circuit which is likewise constrained despite having a valve area of >106mm^2.
 
In my book this is major OOPS. That's two.
 
 
I'm guessing given how "off" these parts are, that they were designed for and intended to be used in a 25 or even 30mm cartridge system. In that situation a 18.5mm base and spacers is no big deal.
 
 

[pattonme]

[HASH]11) Installing the fork cap
 
@cmar143 I need you to chime in on this one. Maybe I'm just stupid, but...
 
The picture shows the fork cap installed on the rod and the spring spacer sitting beside it. Obviously one takes the cap off, slides on the spacer and then reinstalls the cap, right? Of course, easy-peasy. Till you realize in order to reach that silver nut and turn it counter-clockwise against the yellow portion and lock them together you're going to need to compress the spring (0.9+kg/mm mind you) a full 60mm and then another 10mm to clear the black spacer, slap in a forked shim to keep this now VERY highly compressed spring from taking your fingers off, put a wrench on the flats, tighten. Then push down on the spring so you can get the wedge out and watch out at the damn thing tries to put a hole in your ceiling.
 
Basically you need to apply 140lbs worth of pressure to this tool to get that spring to compress that far. I suggest getting friendly with your local line backer or weight lifter.
 
The suspension suppliers and other storefronts will be delighted to sell you this.
 

eg. http://www.traxxion.com/Fork-Spring-Compressor-Kit-4017/
 
But the thing is, it's completely and utterly unnecessary if they but designed it correctly!
 
Take the spring spacer and cut it 50mm from the top (left in pic) so it's just shorter than the golden piece. Then drill the 2 holes in the shorter (right piece). Now all you have to do grab ahold of the lower part and compress the spring about 15mm which you can do without special tools and should the wrench slip while tightening, it won't fling across the room and take your eye out.
 
Put a fender washer between the 2 halves if you want.
 
This doesn't arise to the level of an OOPS, but it's definitely a WTF were they thinking...

[pattonme]

[HASH]12, 13) Stroke limiters
 
The OEM fork limits travel on compression by banging the upper and lower tubes together. It limits on rebound with the use of a top-out spring that sits on the damper rod and under the flared portion. When the lower tube is extending this spring becomes trapped between the damper rod flair and the big piece of metal in the bottom of the upper tube. Secession of movement.
 
In my kit, this same mechanism is employed by mounting the top-out spring on the outside of the cartridge tube.
 
But in the Andreani that big piece of metal is not only perhaps no longer present, but there is no spring mount. Instead they decided to use these lengths of plastic rod to mechanically limit the stroke in either direction. On the face of it, a reasonable solution. Since the cartridge tube is physically and immovably attached to the lower fork leg, they put spacers inside the tube to halt extension (rebound), and spacers inside the spring and riding on the damper rod to limit compression.
 
Looking up what fork travel is supposed to be on the FZ07, our sometimes accurate Shop manual says 5.1 inches or 130mm. If we look at [HASH]13 we see that full stroke is 150mm. That is the distance from hitting the internal spacers when pulling up on the rod, and then pushing in all the way down till the cartridge piston bottoms out on that funky Kayaba valve base. So far so good.
 
Now per [HASH]12 we add the long, barrel-like spacer and then the medium length one and measure how much distance there is between those and the fat O-ring and silver nut with the shaft pulled all the way up. We get 115mm but i'll be generous and call it 120mm since the nut is threaded all the way down and normally it would be a few mm further up. What was the number we're supposed to have? 130mm?
 
Yup, Andreani screwed up and shorted us 10mm of stroke because they used a spacer that was too long. No it's not the end of the world, and there are lots of bikes that use 120mm and a number that go as low as 100mm.
 
But in my book this deserves an OOPS. Number 3.
 

[pattonme]

Conclusions
 
Q: would I buy it?
A: assuming I wasn't well versed in the art of cartridge retrofits and just a normal Joe looking for an upgrade to OEM, in a heart-beat but only at the special discount price. At full price (~$850) given it's gatchas and missteps, probably not since remediation costs money and time and at that point I would go with an AK-20 or other seasoned cartridge retro-fit option.
 
Now if Andreani were providing a 25 or 30mm cartridge kit it would be no contest. Buy it with both hands! but alas...
 
IMO this kit is not a casual DIY upgrade. They clearly intend for it to be installed by a suspension professional who has the requisite tools and know-how. Also I consider the shim stack to be suspect and several bouts of disassembly and re-shimming are in your future. But even out of the box and without addressing any of the errors, it'll run circles around any damper rod system, souped up with GVE or not, at least up to the point where the valving is overwhelmed.
 
 
Hopefully I've been fair in my assessment. I'm pulling on my Nomex suit. Flame away!

[rick]

Think I'll have to re-read all of this a couple times - after lots more coffee - to even understand most of what you've described in such nice detail detail.
 
I have read some owner reviews of this cartridge ( think one was a Triumph Bonneville - or maybe it was a Thruxton) That guy complained of some harshness on compression as it sounds you would predict. He went to a lighter wt oil in that one leg and then was happy.
 
1st, gonna go back to the bit about the spring compressors to see if I can make this operation a bit simpler.
 
http://i48.photobucket.com/albums/f216/rashapir/IMG_0357_zpsmdt0iwsw.jpg
 

[pattonme]

Well geez @rick, that's simple all right. A fine woodworker that guy is too. Note also the nut the spanner is on is right under the cap body, not buried another 60mm down. Andreani should have shortened the Goldenrod part by nearly 2" and lengthened the rod by 2" and moved that nut up to where it was accessible.
 
What is funny, is that all they have to do is take 2 of their inside-the-cartridge spacers out and the rod is magically 2" longer. So all that's left to do is chop 2" off the golden rod and re-thread it and now the nut has "moved" 2 inches closer to the cap body where the preload needed for access is downright manageable. But unfortunately they'll also have to chop 2" out of the needle adjuster to match. But is trivial (for Andreani or machinist) to do.
 
They probably already have the correct-sized parts in their inventory.

[rick]

Oh, I get it now. Well, that fix might be trivial for you perhaps.
 
My EE father had a small manufacturing business when I was a kid. I kinda grew up in a machine shop. Don't quite have the tools anymore. With a 100+ year old Craftsman era house, I found myself with lots of woodworking toys - enough to build my own cabinetry and furniture. Sure would love a nice machine lathe again though. 
 
I actually know guys who jam screw drivers in that Showa fork to push the spring retainer down out of the way to get at that nut under the cap - while it's still in the bike no less. I prefer having a bit more control. lol
 
Won't be pulling that sorta stunt with the Andreani. Fortunately for the average rider, won't need to get in there all that often ( sure sounds like we all will be sooner than later to deal with that lower bushing). For someone who works on these things a lot (dat be yunz), yeah, that would be a big ol pain in the arse.
 
That home made spring compressor of mine (heh, heh, you should see my set-up for breaking tire beeds) is nothing fancier than some scraps
(which as you've guessed, I have stickered stacks of hardwood) 2 bolts to poke into the holes in the collar, some all-thread, nuts, and threaded inserts. Now, if i could only figure out how to spin both screws at the same time.
 
Well, I'm ordering this set-up. The deal on the shock alone is too good to pass up - i didn't see your offer soon enough darn-it. But that OE POS shock needs to go ASAP. When I get around to doing the front, with my fly-weight, I'll have the preload set at full soft and never touch it - the minimal adjustment won't be an issue as i suspect the spring will already be on the stiff side for my preferences anyway. As for the damping and ride quality, only one way to find out. But it's gotta be better.
 
So, are you gonna put it into your SV w/o modification to see how it works out of the box?
 
 

[pattonme]

> So, are you gonna put it into your SV w/o modification to see how it works out of the box?
 
Doubtful. Come on, you expect me not to fix/tweak stuff before I install it? Sure, the scientific method requires I try it in stock trim first, but you guys are keeping me way too busy doing fork upgrades that I won't get around to doing the mods till a lot later.
 
I'd offer to revise and fix the kit I have and install it in a willing FZ07 donor but would need a local (NoVA) tester with patience who wouldn't mind me taking rides on their bike nor the 2 or 3 tear-downs that would likely be needed to fine tune things. Software simulations are only as good as the inputs. Maybe I can talk @howlinhoss into this arrangement, his FZ is not a daily rider I don't believe.
 
Anyone got a line on an inexpensive set of FZ07 forks? (swapping one set out for another keeps the down-time to a minimum)

[gregjet]

Probably unnecessary but will assist Pattonme ( no, we don't have a relationship). Smaller orifaces are not a linear change. One round hole of 10mmmm^3 does not flow the same as 3 round holes of equal crossectional area and the same thickness material ( yes the thickness to diameter matters). The internal surface area of oriface/fluid contact increases as you increase the number of holes. This raises the Reynold number as the fluid velocity streamlines get very close together and restrict considerably more as the diameter and fluid velocity increases. Simply put smaller holes will create much more drag as a square relationship ( not a simple square but certainly not zero nor linear either) of the increase in the number of holes used. Considering we are using quite viscous fluid here the effects will be considerable. For more accurate and wider range control, bigger is better as Pattonme points out.
On as more supportive note for the cartridge manufacturer, if they are creating the kit for RACING , some of these problems are mitigated to some extent, because most tracks don't have square bumps and the fork extention/compression velocities are relatively small compared to the wide range of conditions an actual road fork encounters. This is why setup parameters for road racing ( track) are so finely tuned...because you CAN.

[pattonme]

@gregjet, I appreciate the input. And you're right, the box is clearly emblazoned with "for race only" several places and indeed 1"+ square-shaped bumps are pretty hard to come by on any track that isn't the infamous Nelson Ledges in Ohio. Though hitting one of VIR or Atlanta's curbs as some riders are fond of doing can still pack a serious wallop.

[gregjet]

" infamous Nelson Ledges in Ohio"
Sounds like a track for motards (lol)

[norcal616]

Michigan....Ohio...Illinois...all have lovely roads...thanks to mother nature... The nicest road surface I have ever encountered was at US 131 drag strip...

[pattonme]

@norcal616, you need to come visit west-by-god virginny. Ignoring the coal and lumber trucks and the gravel early in the season, you won't find more lovely, smooth pavement anywhere. Pork-barrel spending at it's finest.

[rick]

Not hard to tell when you cross the state lines out of PA. And it doesn't matter which direction. The roads always get smoother.
 
The Ledges, lol. 

[pattonme]

updated post http://fz07.org/post/41976 with the even greater negative effects on the rebound leg.

[gregjet]

OK I think I may have figured this one.
The flow Around the spacers ( the squarish leading and trailing edges not withstanding) is a single large pipe shaped flow with only the wall and a smooth(ish) internal shape to flow by. The orifaces in the Valve body are not round. This has a huge effect on the flow pattern, possible enough to decrease the effective orifice size ( especially after passing past the vales) by the roughly 15% difference. Just a thought. I am wondering , infact, if the shape MAY not be deliberate because the effect of the hole shape will increase with flow speed. Making a hole that shape has got to be more expensive than a round one, so it may be for a reason such as this??
 

[pattonme]

The orifice shape in the piston is pretty much universal across all pistons I've seen. They take an end-mill and rotate the piston under the cutter so it inscribes an arc. Some of the older style have sharp corners in a wedge-shaped hole (drill round hole then use a broach) which can't be good for flow. So everyone has pretty much moved on to the arc model for pistons this small. At 30mm+ they've returned to the wedge (think slice of pie with tip cut off) since the cutter can actually get into the corner.
 
So @gregjet are you saying that the constricted "pipe" flow may actually be flowing well enough to out-do the piston even though it has a square mm deficit? You seem to be the guy with the knowledge in fluid dynamics. I'm just looking at it from a simple geometry point of view.
 
Never have I seen a cartridge system with these bumpers nor ones this massive. I still contend that they were designed for a much bigger system (eg. 30mm kit) and thoughtlessly used in the 20mm.

[bigtwin]

I received my Adreani cartridge set today from Italy....it has had modifications done compared to the pictures in this thread! The gold part is short and the nut can be tightened with ease....perhaps there are other changes...