reasoning behind the suspension brick on the S18.

[enaon]

Today I run my batch 2 s18 against a batch 3 s18, my suspension felt better, longer travel, faster response, the dial also had different effects. 

In the process of trying to  understanding why that is, it came down to the way the chambers were pumped. In my case, I used the hole on the side to pump my suspension without the brick, the upper valve is easily accessible when the suspension is fully open( after one shaves off the plastic of the fender, it will hit it otherwise). 

Anyway, the difference is huge, so I went to the internet to see if pumping the shock when it is under pressure is something normal. 
I found several videos, some pump the negative chamber first, some the upper, but no one pumps it under pressure. 

I know that kingsong made a video about it, so normally I would be too embarrassed to ask, but for some reason I want to take the chance. 

Taking for granded that when the shock is pumped pressurized due to the brick, it get dump, looses travel and responsiveness,  is that something that is indeed recommended, or is it a side effect of not noticing that the shock can be pumped using the side hole?
 

Edited April 13, 2021 by enaon

[.....]

The suspension brick was merely a workaround for you to be able to get the pump on the valve. Since pressures are mostly preference and mere suggestions, its more important that you get reliable results rather than some precise figure. Your pump itself is probably not calibrated, nor are most pressure gauges. If you can get yours to take air without needing the block, I'd surely do it that way. Dont be surprised if the pressures seem a little lower, but also dont worry about it. Experiment for yourself and just try to use the same pump and fill method each time. Getting the same results is more important than what the actual results show in numeric value. Using the brick or not and what order to fill, is irrelevant. Check the pressures on both chambers on both your wheels at full extension. If they are all the same, they are simply all the same. Motocross shocks are pressurized while NOT compressed. End results matter more than the process.

Edited April 13, 2021 by ShanesPlanet

[enaon]

the problem is that when the negative chamber is pumped with the brick installed, the shock looses travel distance, it never fully extends. I am wondering if that is done on purpose, or by using the brick we are crippling the shock.  

The brick is not needed to pump the s18, the design accommodates for easy access to the upper valve when the suspension is open.

Edited April 13, 2021 by enaon

[.....]

maybe the newer versions. The first version was nearly impossible to inflate without the block. You have to inflate the positive chamber to offset the negative, or it will suck the shock up. I'd simply fill the positive chamber first, to avoid this from happening. The brick has nothing to do with this behavior. I may be misunderstanding your question entirely.

Edited April 13, 2021 by ShanesPlanet

[enaon]

no, I have the old version. The design accommodates for the valve, they have  made a mistake I believe with the screw on the fender, it hits there and cannot move the extra half centimeter needed. I will make you a video, but this is not so importand. 

 

One can emulate the problem, by using the brick to fill the top chamber if he cannot access the valve from the hole, then releasing the brick, then fillthe bottom chamber. The suspension will have full travel. But, if one fills the bottom chamber with the brick on, he will lose some travel, and the suspension will get dump. 

 

Edited April 13, 2021 by enaon

[.....]

No need for a video, I owned a first version from the first pre-order. I have no horse in this race anymore. Perhaps the solution is to simply fill the positive chamber first? Apologies if I've been of little assistance.

Edited April 13, 2021 by ShanesPlanet

[enaon]

sorry if It seemed that I have a problem with your answers, I think that maybe you have thought I just introduced my self to the s18, but I have played a bit with it, like yourself, i did my tests. I am not asking the basics, I am really wondering out loud if what Kingsong recommends is a bad idea. 

have a look here, the problem can be seen at the end, that screw is not allowing for the last half centimeter needed, if you shave it access from the hole is easy.

https://streamable.com/6y1ohj 

 

 

but all that is irrelevant to the real problem. If the down chamber is inflated with the brick on, it looses travel. 

Edited April 13, 2021 by enaon

[mrelwood]

Comparing two S18 units, same or different batch, is tricky. Even if you pump the shocks to exact same pressures with the exact same way, they may feel completely different. The tolerances and manufacturing faults in the linkage system are simply way too large.

 I’ve tried three S18s. One of them didn’t really even change the behavior at different pressures before the owner spent hours to fix just some of the inherent issues. The second wasn’t quite as stuck, but it still wasn’t smooth by a long shot. The third was slightly better as it had been overhauled by the seller shop, but still not nearly free enough to operate smoothly. All three felt distinctly different at the same shock pressures.

[enaon]

40 minutes ago, ShanesPlanet said:

No need for a video, I owned a first version from the first pre-order. I have no horse in this race anymore. Perhaps the solution is to simply fill the positive chamber first? Apologies if I've been of little assistance.

after inflating the bottom chamber the same way, the two s18 are the same, that is not the problem.

 

The problem I saw, is that if the down chamber is inflated under the movement limitation the brick enforces, the shock looses travel distance. To me that looks like a miss usage. What Kingsong recommends is not done be anyone else, all are inflating the shock with it extended. 

The difference is huge, try it out, and then maybe we can figure out why they recommend that. 

 

 

try the following: inflating the bottom chamber, with the brick, and without the brick. 

 

Edited April 13, 2021 by enaon

[.....]

31 minutes ago, enaon said:

sorry if It seemed that I have a problem with your answers, I think that maybe you have thought I just introduced my self to the s18, but I have played a bit with it, like yourself, i did my tests. I am not asking the basics, I am really wondering out loud if what Kingsong recommends is a bad idea. 

have a look here, the problem can be seen at the end, that screw is not allowing for the last half centimeter needed, if you shave it access from the hole is easy.

https://streamable.com/6y1ohj 

 

 

but all that is irrelevant to the real problem. If the down chamber is inflated with the brick on, it looses travel. 

PUtting air in a double chamber shock isnt complex or special to KingSong. Personally I wouldnt put too much worry in what Kingsong reccomends. With tolerances so large, actual pressures will vary greatly for the same shock action. The block was merely intended to assist in airing the shocks. Most wouldnt consider having to modify a panel to gain access, 'easy access'. When you fill the negative chamber first, it will suck the shock up. When the shock is sucked up, you can get to the positive chamber easily, but once you fill it and offset the neagtive, the shock stretches and your positve chamber fitting goes behind the panel. The block enables you to fill the positive chamber w/o worry of the shock moving and making filling impossible. Its been a few months, but I THINK thats how goes. In the end, just do what you have to, to get both chambers aired properly. If you can get to the positive chamber easily without the block, and you can still get to both easily after you fill it... that block is merely a waste of plastic. I cant understand how you lose travel distance once you remove the block. You may gain preload in compare to a shock filled to that psi w/o a block, but thats simply because the block isnt allowing the entire chamber volume to be filled. You may be overthinking this a tad, or perhaps Im just underthinking it.

Edited April 13, 2021 by ShanesPlanet

[enaon]

1 minute ago, ShanesPlanet said:

PUtting air in a double chamber shock isnt complex or special to KingSong. Personally I wouldnt put too much worry in what Kingsong reccomends. With tolerances so large, actual pressures will vary greatly for the same shock action. The block was merely intended to assist in airing the shocks. Most wouldnt consider having to modify a panel to gain access, 'easy access'. When you fill the negative chamber first, it will suck the shock up.

thank you really for the answer, please if you have some time read again what I say, I agree with you, but it something else I am trying to explain.

 

The shock looses distance travel when the bottom chamber is inflated under movement constraint, this is really Kingsong specific, nobody else if doing that, the brick(tm) is all kingsong.

[.....]

3 minutes ago, enaon said:

thank you really for the answer, please if you have some time read again what I say, I agree with you, but it something else I am trying to explain.

 

The shock looses distance travel when the bottom chamber is inflated under movement constraint, this is really Kingsong specific, nobody else if doing that, the brick(tm) is all kingsong.

If you are losing travel, your pressures are wrong. The block is only from Kingsong, because they are the only idiots who put a fill valve in a spot you cant freaking get to very easily. They didnt design the cutout for fill valve room, so they tossed in a chunk of plastic. Air pressure is air pressure. Once the block is removed, the shock has no memory of how it got to the pressures it now resides.

Edited April 13, 2021 by ShanesPlanet

[enaon]

3 minutes ago, ShanesPlanet said:

If you are losing travel, your pressures are wrong.

it looses travel at 50, I could only describe it as misusing the shock, it gets dull too, even an low down pressure. Like it is misused

 

like if inflating the bottom chamber then the shock cannot expand, is resulting in a different shock. Which one did kingsong wanted to use, the normal one, or the one they invented, that is the question.

Edited April 13, 2021 by enaon

[.....]

If your negative pressure is high and your postive pressure is low, you will be preloaded and lose travel. It will feel over dampened and washed out. Keep fiddling with pressures and dont get too hung up on the numbers until AFTER you find a good match. From what I recall, Kingsongs chart was total BS on mine. Of course I also had binding issues and other problems that were effecting my outcomes.

Edited April 13, 2021 by ShanesPlanet

[enaon]

9 minutes ago, ShanesPlanet said:

If your negative pressure is high and your postive pressure is low, you will be preloaded and lose travel. It will feel over dampened and washed out. Keep fiddling with pressures and dont get too hung up on the numbers until AFTER you find a good match. From what I recall, Kingsongs chart was total BS on mine. Of course I also had binding issues and other problems that were effecting my outcomes.

I have done all that.

Top 200, bottom 100, checked after all is done, remember I can access the valves easily

 

1st test: Make the s18 have top200, bottom 100, bottom and top are inflated with the brick on, micro adjustments made later. 
result, dull, lost travel distance.

 

2nd test, the same psi, but bottom chamber is inflated to 100 after the brick is released

result, live suspension, full travel

 

3rd test bottom and top inflated with no brick, result live suspension, full travel,

4rth, the same as third but bottom chamber inflated first, result the same. 

 

conclusion, if bottom chamber is inflated with the brick on, the shock is not behaving properly. 

Edited April 13, 2021 by enaon

[.....]

if you fill a shock that is already compressed, the psi reading you get, will be lower once block removed. Perhaps you are filling it to 100 with block installed, but its much lower once removed?  I'm out of ideas. Seems like there are more ways to do it right than the ONE way you can get it to not work. I'd just NOT do it 'wrong' and not worry about it. They didnt design this with the block in mind. Remember, the block is just a BS (after the fact) workaround. I'd throw the stupid block away and pretend you never saw it.

Edited April 13, 2021 by ShanesPlanet

[enaon]

1 minute ago, ShanesPlanet said:

if you fill a shock that is already compressed, the psi reading you get, will be lower once block removed.

but I told you, I checked the pressures after I finished, all cases were at 200/100.

I think we are just crippling the shock when inflating the down chamber under stress, I will wait for someone with an s18 to test, it is very obvious. 

[enaon]

1 hour ago, enaon said:

https://streamable.com/6y1ohj 

by the way, shaving that plastic off so that one can access the top valve from the side hole, and not hear the sound it makes when hitting it, is easily done using a knife and something to get it hot, without taking anything apart. The plastic is soft, it will melt nicely, and will not affect the screw mechanics. 

Edited April 13, 2021 by enaon

[mrelwood]

1 hour ago, enaon said:

2nd test, the same psi, but bottom chamber is inflated to 100 after the brick is released

If I understood you correctly, you are comparing 200/100psi with block, to 200/100psi without block.

 The pressures in both chambers vary wildly throughout the travel range of the shock. When compressed, the main chamber pressure gets many times higher than when extended. Same goes (inverted) for the negative chamber, the pressure can literally go negative when the shock is compressed.

 A test you can make is to fill the shock without the block to 200/100psi, then insert the block while sitting on the wheel. Then attach the pump to read the pressures from both chambers.

 Those are closer to the values you should be pumping the shock to when using the block method.

[enaon]

5 hours ago, mrelwood said:

If I understood you correctly, you are comparing 200/100psi with block, to 200/100psi without block.

In all cases, I manage to end up with 200/100 after the wheel rests, without the block.  All cases are at the end  the same psi wise. 

 

But, the procedure of inflating the negative chamber' while the brick is place, ends up with a dull shock, no matter the actual psi. 

[Obee]

I am not 100 percent clear on the question.  

However, without the block in place while pumping up the suspension the upper filler port will travel up behind the casing.   The block simply prevents the suspension from expanding beyond the point where the filler port would be obstructed by the outer shell.

Once the suspension is pumped to desired level, weight on the unit will compress the suspension enough to allow the block to be removed.  Once removed the unweighted suspension will expand such that the upper fill port will be hidden underneath the upper case.

[enaon]

1 hour ago, Obee said:

I am not 100 percent clear on the question.  

However, without the block in place while pumping up the suspension the upper filler port will travel up behind the casing.   The block simply prevents the suspension from expanding beyond the point where the filler port would be obstructed by the outer shell.

Once the suspension is pumped to desired level, weight on the unit will compress the suspension enough to allow the block to be removed.  Once removed the unweighted suspension will expand such that the upper fill port will be hidden underneath the upper case.

Sorry about that, it must be my fault, everybody seem to think I am asking something. 

I am not asking, I am saying the S18 has a design that accommodates for the pump to access the top valve, the brick is not needed, and when done the proper way, the shock feels alive. The brick way, leads to a dull shock. 

If one care to try, I would like to hear the results. 

 

[mrelwood]

14 hours ago, enaon said:

In all cases, I manage to end up with 200/100 after the wheel rests, without the block.  All cases are at the end  the same psi wise. 

 

But, the procedure of inflating the negative chamber' while the brick is place, ends up with a dull shock, no matter the actual psi. 

This leaves very few possibilities for it to happen the way you describe. As said earlier, the shock doesn’t know how you pumped it. It only knows the current pressure at any given time, and behaves only by it.

 Does the suspension extend to the topmost position in both cases?

[enaon]

13 hours ago, mrelwood said:

This leaves very few possibilities for it to happen the way you describe. As said earlier, the shock doesn’t know how you pumped it. It only knows the current pressure at any given time, and behaves only by it.

 Does the suspension extend to the topmost position in both cases?

It must be a language barrier, I think I have explained that if tension is applied while the bottom chamber is inflated, it looses travel distance.

Maybe we just have to wait for someone with an s18, and better use of the language.

 

My argument is that kingsong gave instructions on how to misuse the shock, and we all played along for a year. I cannot understand why, maybe they have little to do with the entity that designed the s18. 

Edited April 14, 2021 by enaon

[FinRider]

I dont trust the kingsong pump method at all, haven’t been using the block for ages. I installed a 90 degree elbow extension on the top valve so that it is very easy to fill the positive (top) chamber without having the block.

however, this also means that the pressure guide chart is useless to me... i just go by feel now. Tbh, i dont even know where it is set, i just know that I like the way it feels atm and I am not gonna mess with it.

I may check the pressures tomorrow and report back. I can then put the block in while the pump is connected and see how the pressures change. Would be interesting to know.