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Dagenham Dave
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Discussion Starter · #1 ·
Can someone please explain in simple terms what the Floodgate actually does on a Rock Shox with PopLoc remote?

I have a vague idea after reading some of the posts, but having come from Fox Shox I'm not 100 per cent sure. Is it the same as the "T" on a set of F80RLTs?

Dave V.
 

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http://www.sram.com/en/pike/
the motion control has a compression damper with two fixed-size orifices, one larger than the other.
The size of the little orifice is externally adjustable, up to lockout, with the poplock.
The large orifice is normally closed down by the "gate".
The floodgate sets how much millimeters the plastic spring must be compressed to open up the gate.
The compression of the plastic spring depends on the pressure build up under the gate, and the pressure depends on:
- rate of the plastic spring
- compression speed
- oil viscosity
Last but not least:
- size of the little orifice
So the Floodgate "threshold" is a "lockout threshold" if the Gate is closed, otherwise is a "high speed threshold".
 

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Dagenham Dave
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Discussion Starter · #4 ·
ClaudeFr said:
http://www.sram.com/en/pike/
the motion control has a compression damper with two fixed-size orifices, one larger than the other.
The size of the little orifice is externally adjustable, up to lockout, with the poplock.
The large orifice is normally closed down by the "gate".
The floodgate sets how much millimeters the plastic spring must be compressed to open up the gate.
The compression of the plastic spring depends on the pressure build up under the gate, and the pressure depends on:
- rate of the plastic spring
- compression speed
- oil viscosity
Last but not least:
- size of the little orifice
So the Floodgate "threshold" is a "lockout threshold" if the Gate is closed, otherwise is a "high speed threshold".
Cheers ClaudeFr...Very helpful. Much appreciated.

Dave V.
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Dave V. said:
Yes this article by Angry Asian was very helpful.

Thanks Cyclo-Dude...
I am sorry but that doesnt seem to work that way.
I read in an article that that only works in the boxxer fork, I cant recall if that worked for the Pike or not, but that in the case of the Reba the Floodgate created a platform effect, and it reulated the ammount of force needed for the fork to break into its regular travel.

You will notice this very easily in the REBA.
If you crank the compression you will not get the brake dive and/or anti bob, your fork will move but it will be require more force to o throug its travel.
If you mess with the floodgate then what you get is a platform effect.
Turn the floodgate all the wayand your fork wont move at all, unless you are over 300 pounds. Turn the floodgate all the way off and even if you have the compression in the locked position yur fork will use all of its travel. Unless of course you weight 100 pounds.

So:
Compression locked-floodgate all the way counterclockwise: the fork reacts to most bumps it is almost completely active with some bobbing and brake dive but only in its initial travel; it has more resistance to bottoming out.
Compression locked- floodgate all the way clockwise: The fork doenst move at all, Nada.
Compression unlocked-floodgate all the way couterclockwise:the fork reacts to any sized bumps it is completely active with bobbing and brake dive. PLUSHEST SETTING
Compression unlocked floodgate all the way clockwise: There is no platform feeling, you require the compression to be more than half way to the locked position to experience it.
 

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Cyco-Dude said:
this article by angry asian should help a little.
That was a good article, though I don't think the second setup.......

Low-speed compression damping relatively open for excellent small-bump sensitivity, but firm Floodgate for resistance to bottoming on really big stuff.

works too well that way, unless you consider "spiking" to be resistance to bottoming.
 

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bang
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kapusta said:
That was a good article, though I don't think the second setup.......

Low-speed compression damping relatively open for excellent small-bump sensitivity, but firm Floodgate for resistance to bottoming on really big stuff.

works too well that way, unless you consider "spiking" to be resistance to bottoming.
hmm...i have more testing to do, but it seems that wouldn't work too well. for me, when i have the compression full open and start to turn the floodgate to a firmer setting, the small-bump plushness disappears fast, and you need a bigger hit to activate the fork. in that sense it does provide resistance to bottoming on big hits.

i don't know how much time he had on the pike and reba befor writing this (i believe this was posted on his website over a year ago?). he could probably give a much better description of how it works today. see if there's anything on his forums; i don't have flash installed otherwise i'd look myself.
 

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I find that the floodgate does nothing unless you have upped the compression. And after doing some reading at the RockShox site i think floodgate will only work if compression is increased from full open. Have not tried this mayself yet, but plan on it soon.
 

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kirbster1966 said:
I find that the floodgate does nothing unless you have upped the compression. And after doing some reading at the RockShox site i think floodgate will only work if compression is increased from full open. Have not tried this mayself yet, but plan on it soon.
Cyco-Dude said:
hmm...i have more testing to do, but it seems that wouldn't work too well. for me, when i have the compression full open and start to turn the floodgate to a firmer setting, the small-bump plushness disappears fast, and you need a bigger hit to activate the fork. in that sense it does provide resistance to bottoming on big hits.

i don't know how much time he had on the pike and reba befor writing this (i believe this was posted on his website over a year ago?). he could probably give a much better description of how it works today. see if there's anything on his forums; i don't have flash installed otherwise i'd look myself.
Thats exactly what i explained above :(
 

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Meh.
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kapusta said:
That was a good article, though I don't think the second setup.......

Low-speed compression damping relatively open for excellent small-bump sensitivity, but firm Floodgate for resistance to bottoming on really big stuff.

works too well that way, unless you consider "spiking" to be resistance to bottoming.
I run floodgate about 3/4 closed and compression about 1/2 to 3/4 way. 1/2 way results in a very plush and active initial stroke, but becomes more progressive towards the end stroke, however, it still maintains a very smooth feeling. At 3/4 way it feels more like it's spiking. The travel becomes much harsher, but it's still moving.

The Pike is a little linear, but I have never bottomed mine. I run the maximum oil height. I want to switch to the firm springs though.
 

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bang
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Cyco-Dude said:
for me, when i have the compression full open and start to turn the floodgate to a firmer setting, the small-bump plushness disappears fast, and you need a bigger hit to activate the fork.
i'll go ahead and modify my previous comment: with compression full open and floodgate set firm, the fork is compliant on small or low-speed impacts, such as coasting slowly off of a curb.

what i was doing befor was testing the floodgate setting while riding fast down some stairs (about 5-6 inches tall and maybe three feet long). the fork was harsh with the floodgate set firm (four full turns in or 32 clicks). but coasting down slowly was more compliant.

i haven't spent enough time tinkering with air pressures or compression yet (besides locked out). as it is i have the floodgate set just firm enough to resist bobbing when i'm locked out and hammering out of the saddle, which seems to be about 24 clicks from full open (or three full turns).

what was the question again??? :p
 

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Dave V. said:
Can someone please explain in simple terms what the Floodgate actually does on a Rock Shox with PopLoc remote?

I have a vague idea after reading some of the posts, but having come from Fox Shox I'm not 100 per cent sure. Is it the same as the "T" on a set of F80RLTs?

Dave V.
I am seeing some posts claiming that the floodgate can be set up to resist bottoming. Perhaps I am misunderstanding them, but the floodgate does NOT help resist bottoming. All the floodgate can do is BYPASS (turn off) the compression circut. Whatever you have the compression dial set to is the maximum compression dampening you are going to get. Setting the floodgate fully firm simply means it is NOT going to bypass the compression damper. and what you have left is a simple "unshimmed" damper with no high speed blow off. It is not progressive in the sense of being possition sensitive (it does not ramp up at the end of the stroke) but it does "spike" at higher shaft speeds, thus feeling harsh. I guess you could call that "bottoming resistance", but that is not what the term generally refers to.

The floodgate opens up when a certain amount of pressure builds up at the compression damper. The floodgate adjustment adjusts how much pressure (or resistance) is required to do so. A firm (clockwise) setting means that it requires a lot of pressure to open the floodgate. Two things increase the pressure at the damper: The size of the damper hole (which is what the compression adjustment changes) and the speed of the fluid pushing through it. Smaller hole (which is a high, clockwise compression dampening setting) and faster moving fluid (faster moving shaft) means more pressure. So here is how this can play out in 4 different scenarios:

1) With the compression all the way open (lowest or counterclockwise setting) the floodgate setting makes little difference because the fluid (and therefore the fork shaft) have to move incredibly fast to build up enough pressure to open the floodgate. The floodgate must be set to full soft (counter clockwise, lowering the pressure needed to override the compression damper) in order to have any effect. So what you have is very little compression dampening until you have a big, fast hit, and then you have even less. Personally, I don't see why anyone would want this (compression and floodgate both at min). You'd may as well just loose the compression damper and the floodgate altogether, and save some weight and money. Plus, as I will explain below, the lockout feature is also now totally useless.

2) With a more moderate compression setting, with the Floodgate set to open at higher fork (an fluid) speed you have something like Marzocchi's HSCV that overrides the damper just as it reaches the fluid speed that causes spiking. I used this setting for a while and it felt a lot like my `03 Z1 FR.

3) With a high compression setting (small damper hole), pressure builds up very easily at lower fluid speeds. The floodgate is set up to open at pretty low fuid speeds. This gives you a fork that resists bobbing and diving fairly well, but opens seamlessly up for any bumps. This is my favorite setup.

4) When you "lock out" the fork you are essentially closing the compression damper, so no fluid gets through. Any force the shock experiences will translate to pressure at the compression damper. This is where the setting of the floodgate is most noticable. Full firm setting means the shock is going to be very difficult to move. It is truely locked out. As you lighten it up though, the compression damper is easier to override and the fork can be set to feel locked out, but it will react to larger hits. As you get to the really light settings, the fork has more of a "platform" feel to it. However, I don't think it is accurate to say it's like most platform shocks. Once the floodgate is open you have no control over the compression dampening characteristics. Most platform shocks that I am familiar with have some well though out compression dampening circuts that are in effect even after the platform is breached. For example, Manitou SPV shocks have a compression circut that ramps up at the end of the stroke to resist bottoming, and often you can adjust how much it ramps up.

The trick thing about the floodgate setting is that it has a different result when your fork is locked and unlocked. The compression/floodgate setting that works well in the unlocked position (scenarios #1, 2, 3) may not have the floodgate setting you want when you lock the fork (scenario #4, if you ever do that). For example, for my unlocked setting I run high compression with a very light floodgate setting (scenario 3). I think this is the best feel for me. However, this means that when I use the lockout, the floodgate opens up more easily than I would like. It's not a lockout at all. However, I do notice a little more resistance to movement, and it can be a useful feature when going down something REALLY steep, and it helps me launch drops and jumps more easily. I use it less and less, however, and I am considering trying to ditch the poplock altogether. For people using #1 and #2, however, the locked out setting (#4) will perform much more like a lockout.

Does this answer your question?
 

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kapusta said:
4) When you "lock out" the fork you are essentially closing the compression damper, so no fluid gets through. Any force the shock experiences will translate to pressure at the compression damper. This is where the setting of the floodgate is most noticable. Full firm setting means the shock is going to be very difficult to move. It is truely locked out. As you lighten it up though, the compression damper is easier to override and the fork can be set to feel locked out, but it will react to larger hits. As you get to the really light settings, the fork has more of a "platform" feel to it. However, I don't think it is accurate to say it's like most platform shocks. Once the floodgate is open you have no control over the compression dampening characteristics. Most platform shocks that I am familiar with have some well though out compression dampening circuts that are in effect even after the platform is breached. For example, Manitou SPV shocks have a compression circut that ramps up at the end of the stroke to resist bottoming, and often you can adjust how much it ramps up.
I think you are slightly off there. The floodgate isn't an on/off switch. It does in fact provide damping through the whole stroke when lockout has been breached.

The thing that makes it feel good for trail riding is the fact that the floodgate pressure release is actually linear. Just about every other high end fork is progressive. The linear feel of the floodgate release makes for a plush trail fork, but does not ramp up quite like others. This still doesn't mean there isn't damping through the whole stroke, it takes pressure to keep the floodgate open.

The motion control in the boxxers has an added shim stack to make the floodgate more progressive in damping, which is the inherent trait of shims.

ON top of all this, the motion control damper is IN FACT A PROGRESSIVE UNIT. It has a small air chamber in the swiss cheese unit that get compressed to nearly full capacity. Just the slightest amount of being low on oil in the damper can reduce its progression. If you remove the spring from the fork and compress the fork, you will see that the damper ramps up the spring rate quite a bit in the last 1 inch.
 

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SpawningGround said:
I think you are slightly off there. The floodgate isn't an on/off switch. It does in fact provide damping through the whole stroke when lockout has been breached.

The thing that makes it feel good for trail riding is the fact that the floodgate pressure release is actually linear. Just about every other high end fork is progressive. The linear feel of the floodgate release makes for a plush trail fork, but does not ramp up quite like others. This still doesn't mean there isn't damping through the whole stroke, it takes pressure to keep the floodgate open.

The motion control in the boxxers has an added shim stack to make the floodgate more progressive in damping, which is the inherent trait of shims.

ON top of all this, the motion control damper is IN FACT A PROGRESSIVE UNIT. It has a small air chamber in the swiss cheese unit that get compressed to nearly full capacity. Just the slightest amount of being low on oil in the damper can reduce its progression. If you remove the spring from the fork and compress the fork, you will see that the damper ramps up the spring rate quite a bit in the last 1 inch.
First, I was talking about the motion control on the Pike and Reba. I don't know much about the Boxxer. If the boxxer has a shim stack beyond the floodgate, then what I am saying would not really apply. But as for the Reba and Pike:

I did not say it was an on-off switch, I said it bypasses the main compression circut. Sure, is still has some compression damping going on, but my point still stands (whether that constitutes an on-off switch is an open question). Once the floodgate opens, you just have a larger hole that the fluid is going through. I'm not saying that is a bad thing. That's all HSCV, (or any shimmed damper) comes down to. The point I made that I believe you are refering to is that when the floodgate is combined with a locked out compression to achieve a platform effect, you loose any control beyond the point of the floodgate opening. On the Reba and Pike there is no compression adjustment for when the floodgate is open. You don't really have the ability to fine tune it. Many SPV type forks and shocks have compression adjustments beyond when the platform is breached, and most offer a way to make the compression dampening progressive. The motion control on the Pike and Reba do not offer this. It's not a big deal, as in most of the scenarios I described it is un-necessary.

I have heard conflicting accounts on whether the Pike uses a trapped air bubble to help prevent bottoming and I have not played around with oil levels myself, but either way, an air bubble is NOT the same as progressive dampening. You are increasing the SPRING RATE in the last part of the travel, not the compression dampening. I don't think it really has anything to do with the motion control dampening system. It's a bottom out bumper that uses air instead of rubber. Perhaps we are splitting hairs if we argue about whether this is part of the motion control damper. It is in the motion control unit, but it is not a damper, and it is not adjustable (unless you change the oil level). It does not become firmer with heavier compression and floodgate settings.
 

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kapusta said:
1) With the compression all the way open (lowest or counterclockwise setting) the floodgate setting makes little difference because the fluid (and therefore the fork shaft) have to move incredibly fast to build up enough pressure to open the floodgate. The floodgate must be set to full soft (counter clockwise, lowering the pressure needed to override the compression damper) in order to have any effect.
Do you guess that, or have you experienced such feeling? Could it be true for a heavy rider but not for a light rider?

I like my Reba with full open Compression setting, but haven't tried many different Floodgate settings with that Compression setting. The Floodgate is in the middle now. Nice swallowing of obstacles, no really bad diving or "bobbing", though I don't stand and pedal much, and no bad bottom-outs.

I think that if you really seriously want to grade different, absolute compression damping settings, low and high speed, and say that one is better feeling than the other, then you also need to consider the chosen spring rate and the rider's weight.

The fork's travel over a bump is affected by both spring and damping characteristics. Over one specific shape of bump, you should be able to get the exact same feeling with a softer spring with more compression damping and less rebound damping, as with a stiffer spring with less compression damping and more rebound damping. When then going over other shapes of bumps, the two settings will feel different with one compressing less over some bumps and the other less over others. For example, a deep and gradual bump would compress the setting with a softer spring more, while a square-edge rock would compress the one with a stiffer spring more.

Maybe I like little compression damping because I am on the light side myself and happen to have a spring rate on the stiff side for my weight? I don't know, but I am sure I would like more compression damping if I would choose a softer spring rate. Would it ride better for me and my bumps? I don't know yet :)
 

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anden said:
Do you guess that, or have you experienced such feeling? Could it be true for a heavy rider but not for a light rider?

I like my Reba with full open Compression setting, but haven't tried many different Floodgate settings with that Compression setting. The Floodgate is in the middle now. Nice swallowing of obstacles, no really bad diving or "bobbing", though I don't stand and pedal much, and no bad bottom-outs.

I think that if you really seriously want to grade different, absolute compression damping settings, low and high speed, and say that one is better feeling than the other, then you also need to consider the chosen spring rate and the rider's weight.

The fork's travel over a bump is affected by both spring and damping characteristics. Over one specific shape of bump, you should be able to get the exact same feeling with a softer spring with more compression damping and less rebound damping, as with a stiffer spring with less compression damping and more rebound damping. When then going over other shapes of bumps, the two settings will feel different with one compressing less over some bumps and the other less over others. For example, a deep and gradual bump would compress the setting with a softer spring more, while a square-edge rock would compress the one with a stiffer spring more.

Maybe I like little compression damping because I am on the light side myself and happen to have a spring rate on the stiff side for my weight? I don't know, but I am sure I would like more compression damping if I would choose a softer spring rate. Would it ride better for me and my bumps? I don't know yet :)
Well, I would not have called it a "guess", but yes, I have noticed that as the amount of compression dampening is reduced the efffect of the floodgate is less dramatic. I was in fact guessing that the floodgate would have to be set a FULL soft to kick in. I should have said VERY soft.

I'm not saying which settings are better, I'm just explaining how it works. I just mentioned that I like heavy compression with a light floodgate, others may like something else entirely. That's the great thing about the fork. Certainly if you are a light person with a stiffer spring you would want less compression dampening than a heavy person on a light spring.
 

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kapusta said:
That was a good article, though I don't think the second setup.......

Low-speed compression damping relatively open for excellent small-bump sensitivity, but firm Floodgate for resistance to bottoming on really big stuff.

works too well that way, unless you consider "spiking" to be resistance to bottoming.
actually, a stronger ramping up of the damping gives a much more controlled, positive feel on large huck landings and keeps the fork from blowing through the travel too quickly and jarring the rider. I'm not sure if "spiking" is the best term, but it's what you'd want. Fast DH chatter bumps are where you would want floodgate wide open, similar to hscv marzocchi damping. It's all personal preference, but I like more high speed compression for jumping, less for DH. I think the article is spot on.
 

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Nit-Picking - irrelevant ultimately, but could you all stop say DAMPENING - that means to moisten, or prepare an ink transfer; what we are discussing is called DAMPING.

that is all.
 
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