[ruirocha]

Hi, i would like to tune my monarch RT3 shock, it´s a MM3 tune and i want a lighter tune.
Anyone knows what are the shims that control the Floodgate?
This shock even in the open floodgate position has a lot of compression.

Here is an example of the compression and rebound shims

 

[rlouder]

...

 

[ruirocha]

I think think they are all the same, only the shims thickness and their size change.
I already removed two shims, I have a chart with all the shims size for the different tunes and the difference between medium tune and low are the two shims removed.
The next steep will be the floodgate, increase the difference between the open position and the max position.

 

[car_nut]

You have the high speed shim stack which sits directly against the main piston body. Then, you have the low speed shim stack which sits above it and is built on the manifold with the 3 lobe cut outs in it.

The damper fluid makes its way to the low speed stack by traveling through the center of the damper rod and then into the 3-lobe manifold. In the center of the damper rod is the poppet valve and spring shown in the top of your photo. When you turn the flood gate on, a cam compresses the spring which closes the poppet valve. When the pressure on the valve becomes greater than the spring pressure, the poppet valve opens and allows fluid flow into the low speed shim stack.

So, if you'd like to increase the difference between the on/off settings, you'll need to source a stiffer spring in a length that still leaves the poppet valve open when turned off. Also, you need to be aware of the interaction with the high speed shim stack. There will be a point at which the high speed shim stack will start to bypass oil as well. Since you have a medium tune you hopefully won't reach that point, but it is possible that increasing the spring force won't give you much difference in platform.

Also, any chance you could post that shim stack diagram? I'd certainly like to take a look at it.

 

[ruirocha]

Thanks car_nut for the info So the low speed shims are the bigger ones and the high speed the smaller, correct? I removed the last two bigger shims.

You can see the chart for the different tunes here Big Mountain Cycles - Rock Shox - Monarch RT3/RC3 Hauptkolben mit Shimstack Rock Shox - Monarch RT3/RC3 Plus Hauptkolben mit Shimstack 100010369

 

[car_nut]

I'm not sure I'd say everything of one size is high/low. Mine is a low tune which may be different than yours, but it has a stack of progressively smaller diameter washers for each(which is typical in shim stacks).

In your picture, the damper piston body is the large round object at the top of the "rebound" column. Washers stacked directly against this are the high speed stack. On the "compression" column, the sixth piece up from the bottom is the low speed manifold. One side of this manifold is installed facing the high speed stack. The other side has the three lobed recess. The washers stacked against the three lobed recess are the low speed stack.

I would be careful about just removing washers. There are ports in the damper shaft which line up with the low speed manifolds. I believe the shim stacks need to be maintained at roughly the same stack height to line up correctly. The adjustments are made by varying the diameters of the washers or the order in which they are stacked, not by removing them. The smallest diameter washers at the end of the stack don't affect the damping. They're just there as spacers.

As I mentioned though, the shim stacks aren't what control the platform damping. The exception to this being that the high speed stack damping limits the total amount of platform you can develop after modifying the poppet spring.

 

[ruirocha]

The difference between low and medium tune are the last five shims, low tune only has 3 and mine as shown has 5. I noticed on the chart that the thickness on the low tune are a little bit different about 0,1mm between the first 3 shim from low to medium tune.
Do you think that is a problem?

 

[car_nut]

Sorry, I just reread your posts and realized I was misinterpreting what you were trying to do. Everything I wrote above was about tweaking the flood gate control. For adjusting the overall tune of the shock, you are correct about removing the shims in the high speed stack.

The thickness of the shims definitely matter. If you now have 3 of the 0.1mm shims you will definitely have a lower tune than the 2x 0.15mm/1x 0.10mm. I'd suggest you try leaving the .20mm in place with either 2 or 3 of the 0.10mm shims.

Also, what exactly is it that you're trying to improve? Are you not getting full travel on big hits?

 

[ruirocha]

I'm trying to improve the low speed compression or the overall compression.
My shock even in the open position has a lot of compression, my main goal is to improve sensitivity to improve small bump. My frame has a 2.4 progressive leverage ratio and for my weight, about 70kg, the shock tune is not correct. It is a MM3 tune and I want a low tune.
BTW im not changing anything in the rebound stack.

 

[car_nut]

Well, give it a try, but it may not give you the results you're looking for. Low speed compression also has a lot to do with small bump compliance as well as the rebound speed if you want to prevent the shock from packing. Being that you're on the lighter end of what the frame is likely designed for, you might also want to consider going for a lower weight damping oil. That's the easiest way to reduce the damping overall.

Also, consider charging the IFP to ~25psi less than what SRAM spec's. That tends to take the edge off of sharp hits without affecting travel on big hits.

 

[ruirocha]

I´ll try that too

 

[ruirocha]

Changed damper oil to motorex suspension 2,5w and removed 2 shims. Compression feels better but there is one problem, the rebound. This shock has a medium rebound tune and even with the dialer all way to the fastest still thinking it is a little bit slow.

Gurus out there, what should i do with shim stack to give me a fast rebound???

Is it normal that the monarch rt3 make noise, like sucking the oil? It is well bleeded and this noise is from the first day i had it.

 

[ktm520]

Changed damper oil to motorex suspension 2,5w and removed 2 shims.

Which 2 shims did you remove? I'm currently in the planning stages of revalving my RT3. Also, can you measure the inner diameter of the shims? They appear to be 6mm, but I'd like to confirm before I order shims.

 

[ruirocha]

These are my RT3 shims, with the 2 removed shims on the red arrow.

 

[ruirocha]

The shims are 6mm ID. Please share what are you going to do with the shock

 

[car_nut]

Out of curiosity, does your rebound dial give you an obvious difference in rebound speed? The reason I originally opened mine up is because the rebound control needle was machined too long and jammed shut.

It looks like there's a 14mm x .2mm washer at the number 2 position in the rebound stack. You could swap this with the 10mm x .2mm spacer at the bottom of the compression stack. You'll have to make sure the 14mm won't interfere with anything in that position, though I can't think of anything that should be in the way.

Another option is to put one or two of the shims back into the compression stack and go for a lighter oil weight. The Motorex 2.5 is listed as ~15 cst, as compared to the Golden Spectro Golden (Ultralight) which is listed at 10.4 (see here: Suspension Fluid - Pvdwiki)

 

[ktm520]

My plan is to start by adding a little lsc. I don't really see any good options for this by shuffling shims, so I'm going to order some shims shortly. After that, I might play with the hsr. This is on a Spearfish with a low tune, which is working pretty damn good in stock trim.

 

[ruirocha]

Out of curiosity, does your rebound dial give you an obvious difference in rebound speed? The reason I originally opened mine up is because the rebound control needle was machined too long and jammed shut.

It looks like there's a 14mm x .2mm washer at the number 2 position in the rebound stack. You could swap this with the 10mm x .2mm spacer at the bottom of the compression stack. You'll have to make sure the 14mm won't interfere with anything in that position, though I can't think of anything that should be in the way.

Another option is to put one or two of the shims back into the compression stack and go for a lighter oil weight. The Motorex 2.5 is listed as ~15 cst, as compared to the Golden Spectro Golden (Ultralight) which is listed at 10.4 (see here: Suspension Fluid - Pvdwiki)

The rebound has a lot of difference between full open and full close. From slow in my case to extremely slow. I don't feel any difference on the floodgate dial.

I'll try to change that washer and see what happens.

Is it normal this shock being soo noisy?

 

[car_nut]

Hard to say about the noise. Mine was silent when I got it, but was stuck at 10-15% travel because the rebound was closed off. After reassembling it, I have noise in the 0-15% travel which I assume is because of air. I haven't bothered dissassembling it for another shot at bleeding since I've been having too much fun riding

The low speed manifolds are all air bound when you assemble it per SRAM's instructions. To do it right, I've since come to the conclusion that you need to assemble it and cycle the shock to purge the manifolds/shimstack and then refill the body.

 

[ruirocha]

It looks like there's a 14mm x .2mm washer at the number 2 position in the rebound stack. You could swap this with the 10mm x .2mm spacer at the bottom of the compression stack. You'll have to make sure the 14mm won't interfere with anything in that position, though I can't think of anything that should be in the way.

@car_nut the washer you said to change, is to control the initial rebound or the end stroke rebound?

Were you taking the washer on the blue arrow??

Thank you for your cooperation :thumbsup: