[Neuro]

I have some question for the suspension specialists about my new marzocchi Roco World Cup installed on my Commencal supreme dh 2007. The shocks works well but in my opinion is overdamped for a leverage ratio of 2,6 like Commencal..so I performed a oil change with WP pro Rsf 2,5 wt instead of the original Marzocchi 5wt. The shock works well but it has still too low speed damping.
Anyone knows if there is an internal adjustement for low speed damping?
Thanks in advance.

 

[jonKranked]

try more preload. the only internal adjustment I'm aware of that you could to is adjustments to the shim stack, which I guess which get the job done, however I have no idea how to do so.

 

[SuboptimusPrime]

What do you mean by too much low speed compression? What are the symptoms? You sure you dont have too heavy a spring? Just seems like you should be able to get the shock set up ok without messing with oil and stuff...

 

[vitox]

neuro, the roco comes stock with a fluid that i believe to be of lower viscosity than a regular 5wt, if im not mistaken the stock oil is called aeroshell type41 but dont quote me on it.
for even less compression damping you would need to re-shim the valve.

 

[jonKranked]

this comes highly recommended. mine is getting delivered today.

 

[Biscuit]

I have some question for the suspension specialists about my new marzocchi Roco World Cup installed on my Commencal supreme dh 2007. The shocks works well but in my opinion is overdamped for a leverage ratio of 2,6 like Commencal..so I performed a oil change with WP pro Rsf 2,5 wt instead of the original Marzocchi 5wt. The shock works well but it has still too low speed damping.
Anyone knows if there is an internal adjustement for low speed damping?
Thanks in advance.

I've never heard of anyone complaining that a roco had too much low speed damping. You may just have too stiff of a spring.

Try playing around with the air pressure (lower). I haven't seen the insides of the roco (yet) but from my limited knowledge I'm pretty sure higher air pressure affects high speed compression, and would have small effects on low speed. But not much. (this is my understanding of the insides of that shock; someone please correct me if I'm wrong).


Another thing, when you switch oil, and re-charge with air. You should charge with the shock in the compressed position. As you fill it with air, the shock shaft will extend. This is a low-tech way of establishing the piston position in the reservoir.

If the air volume isn't enough there will be nowhere for the piston to go as the shock develops pressure and you get hydrostagnificrasomething.. it's a big word that means your shock doesn't work right. Basically, as pressure develops inside the shock the piston moves back and forth to relieve some of this (the valving controlls the rest). You physically can't compress a lower volume of air as much as a bigger volume (duh) and one of the primary functioins of the resi won't work. By the same token, greater air pressure will resist compression more than lower pressure (duh again). I believe the pressure range is on zocchi's website/manual.

 

[jonKranked]

if i'm not mistaken, the primary function of the air pressure is bottom out resistance. However, the air pressure *does* affect rebound and compression. How much and in exactly which ways, i'm not sure. Its a matter of finding your sweet spot. also, what weight coil are you using, and how much do you weigh?

 

[Biscuit]

While the internals and design are completely different, the Cane Creek website has pictures that sort-of show how the air and piston work in a shock.

http://www.canecreek.com/db_4_way.html

Their internal design functions completely differently than a roco though, so I don't believe their air/nitrogen pressure is even adjustable.

The Roco air chamber partially doubles as a spring which is one way it affects rebound and compression. The DB does not.

 

[Jm_]

if i'm not mistaken, the primary function of the air pressure is bottom out resistance. However, the air pressure *does* affect rebound and compression. How much and in exactly which ways, i'm not sure. Its a matter of finding your sweet spot. also, what weight coil are you using, and how much do you weigh?

The primary function of air pressure is to allow room for fluid expansion.

 

[jonKranked]

The primary function of air pressure is to allow room for fluid expansion.

not what i meant. i meant that you BOR is the primary thing affected/controlled w/ air different air pressures.


ps i didn't know fluid could expand that much inside a shock

 

[Biscuit]

The primary function of air pressure is to allow room for fluid expansion.

I spent three paragraphs trying to explain what you just stated in one sentence.

 

[vitox]

not what i meant. i meant that you BOR is the primary thing affected/controlled w/ air different air pressures.

well not really, not on the roco at least, because you only have a small adjustment range (180 to 220psi). air volume on the other hand will have a more definite impact on bottom out resistance.

 

[jonKranked]

well not really, not on the roco at least, because you only have a small adjustment range (180 to 220psi). air volume on the other hand will have a more definite impact on bottom out resistance.

do the '07 roco's have air volume adjustment? i have an 06 and there's no such feature. air pressure adjustment is the closest i got.

 

[Biscuit]

not what i meant. i meant that you BOR is the primary thing affected/controlled w/ air different air pressures.


ps i didn't know fluid could expand that much inside a shock

Because higher pressure resists fluid expansion (i.e. pressure) it indirectly increases your high speed compression and BOR. DHX's allow you to turn a knob to decrease the size of the "expansion chamber" which makes everything more progressive, yada yada yada.

 

[Biscuit]

do the '07 roco's have air volume adjustment? i have an 06 and there's no such feature. air pressure adjustment is the closest i got.

No. The only way you could adjust this would be very rudamentary and low-tech.

What I described above about charging the shock in the compressed position which allows for the piston to move and establish an air chamber. If you wanted more BOR, you could play around with not having the shock fully compressed (say, start filling with air with 1/4" of shaft showing). Basically making your air chamber smaller.

But this would be a complete trial and error process that would be difficult to replicate.

* this is actually what the zocchi compression adjuster is for - BOR - last 1/3 of travel *

 

[zero knowledge]

I tried a Roco on my Sunday and the stock valving provides too much damping for both compression and rebound. You will have to change most of the shims if you want it tuned properly. I cannot source some of the shims needed and for now I'm just experimenting with removing some of them in order to decrease the low speed compression and both low and high speed rebound, but still the LS compression is perceptibly more than the DHX with "sunday tune." If you are willing to modify your shock and can find different shim sizes with 0.10mm thickness (most of the stock shims are 0.15mm thick), I can send you a proposed lighter valving.

On a different note, the lighter valving changes the larger diameter compression shims (0.15mm) with thinner ones (0.10mm) and 0.10mm shims provide ~1/3 the resistance of 0.15mm shims. So the 1/3 LS compression on the "sunday tune" seems a very good estimate. On the rebound side, the HS rebound is again ~1/3 of the stock and the LS rebound is considerably less than 1/3 - something closer to ~1/8.

And isn't the compression adjuster on the Roco in fact a low speed adjuster? It is on the reservoir, at low shaft speed and on the min setting oil can bypass the shims in the reservoir freely and on the max setting it is forced to go trough the reservoir shims.

 

[jonKranked]

And isn't the compression adjuster on the Roco in fact a low speed adjuster? It is on the reservoir, at low shaft speed and on the min setting oil can bypass the shims in the reservoir freely and on the max setting it is forced to go trough the reservoir shims.

i'm pretty sure its high speed. its listed on the marz site as HSCV.

 

[Biscuit]

I tried a Roco on my Sunday and the stock valving provides too much damping for both compression and rebound. You will have to change most of the shims if you want it tuned properly. I cannot source some of the shims needed and for now I'm just experimenting with removing some of them in order to decrease the low speed compression and both low and high speed rebound, but still the LS compression is perceptibly more than the DHX with "sunday tune." If you are willing to modify your shock and can find different shim sizes with 0.10mm thickness (most of the stock shims are 0.15mm thick), I can send you a proposed lighter valving.

On a different note, the lighter valving changes the larger diameter compression shims (0.15mm) with thinner ones (0.10mm) and 0.10mm shims provide ~1/3 the resistance of 0.15mm shims. So the 1/3 LS compression on the "sunday tune" seems a very good estimate. On the rebound side, the HS rebound is again ~1/3 of the stock and the LS rebound is considerably less than 1/3 - something closer to ~1/8.

And isn't the compression adjuster on the Roco in fact a low speed adjuster? It is on the reservoir, at low shaft speed and on the min setting oil can bypass the shims in the reservoir freely and on the max setting it is forced to go trough the reservoir shims.

If you end up playing with shims keep us updated. I'd be interested to see how it feels. Take photo's too please.

I also run a Roco on a Sunday and simply swapped the oil for a mixture of Redline 2.5wt and "Like Water" shock oil. Lowering the viscosity of the oil should have roughly the same outcome as using thinner shims.

And to my knowledge the compression adjuster on the roco WC is actually only the last 1/3 of the stroke. Mostly providing bottom out resistance.

I think the compression on the Roco TST is low speed though, since it's specifically marketed for pedaling. Haven't ridden one though.

 

[zero knowledge]

If you end up playing with shims keep us updated. I'd be interested to see how it feels. Take photo's too please.

I also run a Roco on a Sunday and simply swapped the oil for a mixture of Redline 2.5wt and "Like Water" shock oil. Lowering the viscosity of the oil should have roughly the same outcome as using thinner shims.

And to my knowledge the compression adjuster on the roco WC is actually only the last 1/3 of the stroke. Mostly providing bottom out resistance.

I think the compression on the Roco TST is low speed though, since it's specifically marketed for pedaling. Haven't ridden one though.

What is your weight and spring rate? Does that redline mixture provide you with light enough compression and rebound damping? Right now I'm using motul shock oil, which is 16.1 cst@40C and redline's like water is 5.5 cst@40C. I'm still playing with removing some shims and swapping others. From the 6 larger diameter comp shims on the piston (2x 22mmx0.15mm, 2x 21mmx0.15mm, 2x 20mmx0.15mm) I left only 2 (1x 22mmx0.15mm, 1x 20mmx0.15mm) and this provides much more LS comp damping than the sunday tuned dhx. I'm not satisfied yet, I might try a few more things when I get the time or just wait until I get some 0.10mm shims or redline oil.

 

[vitox]

I tried a Roco on my Sunday and the stock valving provides too much damping for both compression and rebound. You will have to change most of the shims if you want it tuned properly. I cannot source some of the shims needed and for now I'm just experimenting with removing some of them in order to decrease the low speed compression and both low and high speed rebound, but still the LS compression is perceptibly more than the DHX with "sunday tune." If you are willing to modify your shock and can find different shim sizes with 0.10mm thickness (most of the stock shims are 0.15mm thick), I can send you a proposed lighter valving.

On a different note, the lighter valving changes the larger diameter compression shims (0.15mm) with thinner ones (0.10mm) and 0.10mm shims provide ~1/3 the resistance of 0.15mm shims. So the 1/3 LS compression on the "sunday tune" seems a very good estimate. On the rebound side, the HS rebound is again ~1/3 of the stock and the LS rebound is considerably less than 1/3 - something closer to ~1/8.

And isn't the compression adjuster on the Roco in fact a low speed adjuster? It is on the reservoir, at low shaft speed and on the min setting oil can bypass the shims in the reservoir freely and on the max setting it is forced to go trough the reservoir shims.

word

i also ran into this problem, although i was actually trying to get more LS comp damping at that time, there very little space to fiddle around and you need very thin shims to get it to work.

 

[vitox]

do the '07 roco's have air volume adjustment? i have an 06 and there's no such feature. air pressure adjustment is the closest i got.

you can fiddle a bit around with the air volume, thats about it, like on all shocks you (dont know about romic tho) have some wiggle room, but i wouldnt call it an "adjustment"

 

[Biscuit]

What is your weight and spring rate? Does that redline mixture provide you with light enough compression and rebound damping?

Since your playing with shims I bet you know a bit more than I do about suspension tech. Most everything I know I learned from my buddy Pete who is pretty into motorcycle suspension.

At sea otter I got trapped with him and the development guy for the Can Creek DB during the rain storm and I thought my head would explode.

I weigh 190 with gear. Run a 350# spring. And currently have about 200psi in the chamber. My oil mixture was 3:1 Redline 2.5wt and LikeWater (wich is rediculously non-viscous). I've also got the compression knob all the way out, partially because I had to take it off to mount it on the sunday and haven't taken the time to pull the shock off to turn it. The rebound is almost all the way out, but it's pretty much right where I want it (pretty fast).

Performance wise it feels great and reacts extremely well to trail variation. It is lacking on really big hits and hard landings, so my next try will be to "fiddle" with decreasing the air volume to make it more progressive.

Lately I've been trying to get my fork to match the rear shock (888rc2x) which is one med, one firm spring. Right now it feels pretty good, but I'm not getting the tuning range I want out of the end stroke (the "2x"). I'll probably increase the oil volume a bit and not rely on the "2x" so much.

 

[bob]

You are right Vitox, the Roco oil is the same as the Aeroshell (and also Royco).
Actually it is "designed for use in aircraft, missiles, auto pilots, shock absorbers etc".

Adjusting the air pressure will mostly just effect the bor, it is not like the DHX, 5th and Swinger.

If you are changing shims you must be sure that the total shim stack height is about the same, because the bolt must be in the same place.
If not it will affect the rebound adjuster, and if the shim stack height is reduced too much the bolt will stop since it only has a limited amount of threads.
I would recommend using a good torque wrench to be sure that the shims have the right preload (20nm).
If you are adjusting it for the first time be aware that the bolt is loctited and you may need to heat it up.
When reassembling apply a drop of Loctite 2701 (270).

The compression adjuster is adjusting the bypass hole on the foot valve (on the way in to the reservoir).
Even though Marzocchi call it a high speed adjuster it will affect the low/mid speed compression a bit.

 

[vitox]

You are right Vitox, the Roco oil is the same as the Aeroshell (and also Royco).
Actually it is "designed for use in aircraft, missiles, auto pilots, shock absorbers etc".

Adjusting the air pressure will mostly just effect the bor, it is not like the DHX, 5th and Swinger.

If you are changing shims you must be sure that the total shim stack height is about the same, because the bolt must be in the same place.
If not it will affect the rebound adjuster, and if the shim stack height is reduced too much the bolt will stop since it only has a limited amount of threads.
I would recommend using a good torque wrench to be sure that the shims have the right preload (20nm).
If you are adjusting it for the first time be aware that the bolt is loctited and you may need to heat it up.
When reassembling apply a drop of Loctite 2701 (270).

The compression adjuster is adjusting the bypass hole on the foot valve (on the way in to the reservoir).
Even though Marzocchi call it a high speed adjuster it will affect the low/mid speed compression a bit.

hey waddaya know we have a real expert here!
en mann etter mitt eget hjerte kan man si.

hey bob have you done any comp stack modifications, if so would you suggest going at the stack at the piggyback or the main piston?

 

[bob]

Well if you want less compression damping (faster, less resitance) i would go for changing the shims on the main piston.
If you were to open the foot valve to much (on the way into the piggyback) the shock may just push the all the oil throught into the piggyback and create a vacuum on the other side of the main piston (result= cavitation and almost no damping).
So the most safe way for less compression is the main piston.
I have had good luck with changing the diameter of som of the first shims from 0.15 to 0.1 and then add the needed millimeters on the end of the shim stack.
For example if you change 3 shims from 0.15 to 0.1 than you add an 0.15 shim with an diameter of 11mm on the end of the shimstack.

One thing must be said, the Roco has a very good shimstack so there are in the most cases no need for changing shims.
And if you want too change shims, do one job at the time, and be sure you know what you do.

At the rebound side there is a "straight" shimstack, 3*0.15*18mm.
If you want it a bit faster on the mid speed rebound than you could try to change the middle shim from 18mm diameter to 17mm.

 

[jonKranked]

bob - do you have any pictures of the piggyback shimstack? or any of the internals in general? i'm curious to see what the insides look like.

also, i put the 2.5wt redline in my roco, feels amazing. to those that add "like water" to the mix: have you run just straight 2.5 redline? is there a noticable difference between the 2?

 

[dh_newbie]

Could anyone show us some picture of this modification. I will have the roco at this week. I would like to see all your advice and inform before I install it on the bike.

 

[_*sTiTcHeS*_]

i'm scared to get a roco wc for my commencal now.

it has a 3:1 leverage ratio.

do you sus. techs think that i will have to replace the oil, adjust the shims, or do any other mods to get the shock as pedal retarded as i like.

i hate any sort of compression damping, pedal platforms, and **** like that.

 

[joelsman]

your commencal will be fine with a rocco stock, dw link bikes are special needs bikes.

 

[jonKranked]

yea, the commencal's come spec'd with the rocco, you're fine. any shock that goes on a sunday (or any dw link) need a custom tuning because of the low leverage ratio (can't remember what it is).

The only thing you might have to do to your rocco is top it off with oil (like any marz product). Dunno if you have to do it to the 07 shocks, I had to do it to my 06.

 

[dhkid]

the commencals ratio isn't too far off from the sunday. 2.75/7in 3/8in anyways, i have a friend who complains that his roco on his commencal is over damped also. i am happy with my dhx..

 

[Neuro]

I concord with Dhkid. Leverage ratio is more important than type of linkage so Commencal is similar to Sunday in the speed shaft of the shock so I decided to sold my Roco because also with Red Line 2,5 was still overdamped. I bought a DHX 5.0 2007. Tried last week and it was very very good. With Fox DHX 5.0 standard shimmed my Commencal works very very well and is more active over small bump, and the range rebound setting is wide.

This is my first setting and it is very good for me: Fox 2007 DHX 5.0 on Commencal Supreme dh 2007. I weight 73 kg or 162 lb:

Spring 300lb with 1 turn of preload
130 psi Bost valve pressure
propedal full out
Bottom out in the middle position
rebound four clicks from fully open

Any suggestion?

 

[jonKranked]

this is not a DHX thread. read the title. stop derailing the thread.

 

[dhkid]

I concord with Dhkid. Leverage ratio is more important than type of linkage so Commencal is similar to Sunday in the speed shaft of the shock so I decided to sold my Roco because also with Red Line 2,5 was still overdamped. I bought a DHX 5.0 2007. Tried last week and it was very very good. With Fox DHX 5.0 standard shimmed my Commencal works very very well and is more active over small bump, and the range rebound setting is wide.

This is my first setting and it is very good for me: Fox 2007 DHX 5.0 on Commencal Supreme dh 2007. I weight 73 kg or 162 lb:

Spring 300lb with 1 turn of preload
130 psi Bost valve pressure
propedal full out
Bottom out in the middle position
rebound four clicks from fully open

Any suggestion?

sorry to derail the thread even more, but i just wanna answer this...

not sure how much sag you are running, the 300 might be a bit too soft for you. if you are running around 30% sag then thats great. i found that the linkage ramps up enough that i dont need much bottom out resistance. i run my bottom out half a line from fully out. and pressure at around 90.

 

[Neuro]

this is not a DHX thread. read the title. stop derailing the thread.

I opened this thread and I report the difference between the Roco that i had two weeks ago and the new shock dhx 5.0 that installed next week on my bike...what is the problem?
I have mistaken something?
@ dhkid: Thanks for the support.

 

[dh_newbie]

any news of picture?

 

[vitox]

i posted a picture a way back of the internals, it didnt have the piggyback shimstack laid out though, but its there

 

[Biscuit]

i posted a picture a way back of the internals, it didnt have the piggyback shimstack laid out though, but its there

Neat: http://www.ridemonkey.com/forums/showthread.php?t=164761&highlight=roco

 

[_*sTiTcHeS*_]

just a quick question you guys would probably know:

does a the majority of ti springs fit on the roco wc? like fifth, manipoo, renton,...

its funny that i've never had a coil shock in my whole life. im still not convinced on them yet.

i need the OEM size so im going to get a roco off an online bike shop store and that is the reason for the Q's

 

[dhkid]

just a quick question you guys would probably know:

does a the majority of ti springs fit on the roco wc? like fifth, manipoo, renton,...

its funny that i've never had a coil shock in my whole life. im still not convinced on them yet.

i need the OEM size so im going to get a roco off an online bike shop store and that is the reason for the Q's

yea, springs from 5ths manipoo and fox(dhx) will fit it, that includes rcs ti springs ect. the size you need for a supreme dh is a 2.75x8.75. funny how you say you aren't convinced about coil shoxs.. most ppl would say otherwise. no air spring to blow up and after all, its the coil that came first.