[skatetokil]

So I have always been a "set it and forget it" kind of rider but in making the switch from a Swinger 4 Way to a Roco RC on my Iron Horse Kumicho I noticed some changes that I'm having trouble adjusting to. I think it might be a tuning issue so I hope you all will share your settings.

I got rid of the swinger because of the dreaded "dead feeling." The bike was unresponsive and nearly impossible to jump unless I sped the rebound up so much that it was prone to catapulting me on steep lips.

The roco is much improved and makes the bike feel more balanced, easier to corner, jump and change directions. I believe I'm faster overall with this shock on the bike, but the one area where I know my performance has degraded is through chunky rock gardens (see: snowshoe). The back end just likes to wander around on me, and I get tossed off line and have to grab the brakes which makes the suspension perform even worse. I can sometimes see that there is a faster line through the air, a gap I could hit if I had the balls, but I've always been more of a plow rider than that guy who jumps off every rock.

I currently run 35% sag, 190 psi, almost max fast rebound, and and almost min compression and I'm wondering what to play with first. Havent touch the IFP but maybe that's something I should consider. Anyway, thanks for your help.

 

[jonKranked]

how much do you weigh? 190 PSI sounds like a lot or air pressure.

 

[Leppah]

I have a Rocco on my Kona DH bike. I sent it away to PUSH and it's worked awesome since then. No complaints at all. But mine is the coilover. I can't remember which model. Maybe the WC?

 

[dhkid]

190 psi is normal with a roco, you cant compare it to other shocks. it does fak all to stiffen up the shock and does not change the compression damping. all it does is act like an air spring. the high pressures are needed because it runs such a low oil weight.

i would open it up and reshim it. if you are comfortable playing with shocks that will definitely be the way to go. i have found that rocos do tend to be a bit over damped for lower leverage bikes, yours being one. dont bother messing with the compression shim stack in the piggy back, just the one on the main piston. dont bother with the ifp.

sneaky hint, you can run 2.5 wt oil in there and get your rebound adjuster to actually have a working range of adjustments.

 

[Kanye West]

190 psi is normal with a roco, you cant compare it to other shocks. it does fak all to stiffen up the shock and does not change the compression damping. all it does is act like an air spring. the high pressures are needed because it runs such a low oil weight.

Nope. They use the same oil as any other major shock. Pro Circuit PC-02 is the best stuff to use in the Roco's in my own experience, and by Marzocchi's recommendations.

Using 2.5w oil really messes with the compression and rebound ranges. You're better off re-arranging the shims.

 

[Udi]

They use the same oil as any other major shock.

That's a blanket statement, virtually all shocks on the MTB market use different brands and weights of oil. Given that even different rated weights change drastically in terms of actual viscosity over brands (without considering that different shocks use different oils in terms of even rated weights in the first place) I'd say you're flat out wrong, really.

I find that if you're planning on changing from the stock oil in a shock (or don't know what its actual viscosity is), it's best to switch it over to something that you know the specs of, and then if it's in roughly the right range of damping, fine tune with shims / adjusters from there. Either that, or find out what the stock oil is and use the same stuff.

 

[Udi]

but the one area where I know my performance has degraded is through chunky rock gardens (see: snowshoe). The back end just likes to wander around on me, and I get tossed off line and have to grab the brakes which makes the suspension perform even worse.

I currently run 35% sag, 190 psi, almost max fast rebound, and and almost min compression and I'm wondering what to play with first. Havent touch the IFP but maybe that's something I should consider.

Just based on what you've said there (and the fact that you didn't have this problem with the more stable shock) it'd seem that running just a little more damping might be beneficial... I don't think you need to go wild pulling the shock apart like suggested above (just yet anyway! damn all these suspension geeks ).

I'd suggest running a little more compression damping and a little more rebound damping, the extra rebound will stop it kicking back too much and tossing you offline, and the extra compression will stop it using too much travel on the bigger impacts through the rock garden (leaving less extension distance to kick you back with).

Ideally you'd try each of those changes one at a time, so maybe on the same run you're having this issue, try running a few clicks more compression one run to see what that does, and the next run reset the compression and run the rebound in a few clicks more to see what that does... and based on the results you might find a happy medium (between changes to just one, or both of the settings).

Hope that helps! IFP depth only affects progression so don't worry about that unless you have issues using all the travel or are bottoming out excessively, and chamber pressure is usually best run towards the minimum of what's recommended.

 

[JohnnyC]

Just based on what you've said there (and the fact that you didn't have this problem with the more stable shock) it'd seem that running just a little more damping might be beneficial... I don't think you need to go wild pulling the shock apart like suggested above (just yet anyway! damn all these suspension geeks ).

I'd suggest running a little more compression damping and a little more rebound damping, the extra rebound will stop it kicking back too much and tossing you offline, and the extra compression will stop it using too much travel on the bigger impacts through the rock garden (leaving less extension distance to kick you back with).

Ideally you'd try each of those changes one at a time, so maybe on the same run you're having this issue, try running a few clicks more compression one run to see what that does, and the next run reset the compression and run the rebound in a few clicks more to see what that does... and based on the results you might find a happy medium (between changes to just one, or both of the settings).

Hope that helps! IFP depth only affects progression so don't worry about that unless you have issues using all the travel or are bottoming out excessively, and chamber pressure is usually best run towards the minimum of what's recommended.

Yup this would definitely be the best way to do it, I wouldn't go diving in changing the shims until you've exhausted all your tuning possibilities with the external adjustments.

 

[slowmtb]

JohnnyC - you changed your sig' to Rotovegas :biggrin:

Anyway, he states that he is using almost max fast rebound, is it packing down causing the rear to skip around / not follow the terrain ?

Thoughts?

 

[Kanye West]

Also, the compression adjuster on the Roco does not begin to function until it is halfway through it's range. Use that as a baseline. If you look at the WC valve, the needle on the adjuster has to go through exactly half of it's range before it even begins to close off any ports. A common modification (if you can do it clean) is to raise the ports in the larger brass piece to about twice their height - the adjuster seems to thread out from top kinda (reverse thread), so matching the height to the adjuster bottom-out yields excellent results such as improved flow and more functional range.

Udi - I'm well aware of the mislabeled oil weights, different manufacturers, inconsistent measuring blah blah blah. If you look at the Torco, Spectro, Redline, Maxima and Pro Circuit oil viscosities that all the big manufacturers are using in their shocks, they're really close to the same viscosity, like +/- 10%. Sorry, but your opinion is wrong (I'm going to get some mileage off of that one I think).

 

[JohnnyC]

JohnnyC - you changed your sig' to Rotovegas :biggrin:

Anyway, he states that he is using almost max fast rebound, is it packing down causing the rear to skip around / not follow the terrain ?

Thoughts?

Haha yup I didn't realise till you pointed it out

It wouldn't be packing down because of the fast rebound, it would be blowing through too much travel with no compression damping then he has the rebound damping fast so it can recover and not pack down.

A bit more damping both ways should help alot, the rear wheel would only be using as much travel as it needs instead of flapping up and down and getting out of control

 

[slowmtb]

Haha yup I didn't realise till you pointed it out

It wouldn't be packing down because of the fast rebound, it would be blowing through too much travel with no compression damping then he has the rebound damping fast so it can recover and not pack down.

A bit more damping both ways should help alot, the rear wheel would only be using as much travel as it needs instead of flapping up and down and getting out of control

Ah yes, I see what you mean. I read it as " has heaps of rebound wound in" eg: slow return oster_oops:

 

[dhkid]

Nope. They use the same oil as any other major shock. Pro Circuit PC-02 is the best stuff to use in the Roco's in my own experience, and by Marzocchi's recommendations.

Using 2.5w oil really messes with the compression and rebound ranges. You're better off re-arranging the shims.

like udi said, that's kinda a broad statement. and dont they run something close to 1wt oil, like water stuff? dhx runs 10wt, 5th runs 5wt, the new manipoos do run similar oil weights to the roco tho. so they dont really run the same oil weights as other shocks.

yes, i wont recommend running the 2.5 wt with out changing the shims, but if you are going to mess with the shims it works much better with 2.5 wt. the rebound is a copy of the 5th element one and that was designed around 5wt oil. with the stock oil, only the last like 5 clicks do anything and slow down the rebound significantly. with the 2.5 wt, you actually end up with a useful range of rebound damping, not fast all the way then slows down like mad on the last few clicks.




Udi- based on his first post, he said he was close to running his rebound full open and minimum compression. so based on that and the fact that i already know that rocos tend to be overdamped for lower leverage bikes re shimming it would be me recommendation. what i think is going on with his shock is there is too much HSC and its being harsh.

 

[Udi]

Udi - I'm well aware of the mislabeled oil weights, different manufacturers, inconsistent measuring blah blah blah. If you look at the Torco, Spectro, Redline, Maxima and Pro Circuit oil viscosities that all the big manufacturers are using in their shocks, they're really close to the same viscosity, like +/- 10%. Sorry, but your opinion is wrong (I'm going to get some mileage off of that one I think).

Hate to break it to you, but both times you've used that line I've actually been right. You're more than welcome to use my corny lines against me but please let it be when it's legitimate.

I'm quite sure you're actually wrong on this account, and would love to see figures to prove otherwise.

Please give oil viscosities (in cSt) for Manitou, Progressive, Fox, BOS, and CCDB - that should be a good start. The fact that you suggested they were the "same" makes you wrong by default, but I'm keen to see the hole get deeper.

Udi- based on his first post, he said he was close to running his rebound full open and minimum compression. so based on that and the fact that i already know that rocos tend to be overdamped for lower leverage bikes re shimming it would be me recommendation. what i think is going on with his shock is there is too much HSC and its being harsh.

I suspect it's just kicking back a little excessively, but anyway - it'll be better to see if it's fixable with adjusters before pulling it apart, as his post alluded to the fact that he hadn't really played with them yet. Logically, that'll be the place to start. Keep in mind that you do seem to like a lot less damping than some of us here (in both directions from what I can gather), my friend ran the roco on a sunday for a little while and we didn't really think it was overdamped as such.

Also, without rider weight and spring rate, you can't really say it's overdamped IMO... like I said, worst case scenario if the adjustments don't help things, re-shim. But it's illogical to attack things in the opposite direction.

 

[dhkid]

yea fair enough. the shocks i worked on were for supremes, and not mine. for people who actually weight a normal amount. was overdamped for them too.

i do like fast rebound, but not fak all compression damping. i cant ride a stock dhx anymore because it feels like a spring with no damping to me now.

 

[captainspauldin]

Nope. They use the same oil as any other major shock. Pro Circuit PC-02 is the best stuff to use in the Roco's in my own experience, and by Marzocchi's recommendations.

Yeah the Marz Tech over at MTBR recommended that stuff.. bought it and was ready to rebuild my ROCO, then I called Marzocchi to get a new rebound knob for my ROCO and they basically talked me out of rebuilding the ROCO on my own. I'm pretty mechanically inclined and used to working on suspensions(rebuilt my boxxer, and removed the blackbox speedstack, lowered a pike, rebuilt a totem), but I've never really done anything to a rear shock short of swapping out the high volume canister on my dhx air.. I've looked at the powerpoint to rebuild it, it really doesn't look that bad, any thoughts?

 

[dhkid]

the person you talked to at marzocchi probably has been brain washed with marzocchi tech manuals.

INCORRECT USE CAN RESULT IN INJURY AND OR DEATH!
written about 3 times on every page.

its not that hard really, if you want to be careful and make sure there is no air then just put it back together in a bucket of oil. once you get the hang of it you dont need one.

 

[captainspauldin]

the person you talked to at marzocchi probably has been brain washed with marzocchi tech manuals.

INCORRECT USE CAN RESULT IN INJURY AND OR DEATH!
written about 3 times on every page.

its not that hard really, if you want to be careful and make sure there is no air then just put it back together in a bucket of oil. once you get the hang of it you dont need one.

yeah, submerged in oil right? The tech mentioned that, I didn't really understand that part, but maybe b/c I didn't really read the manual, just sorta looked at the pictures..

 

[jonKranked]

yeah, submerged in oil right? The tech mentioned that, I didn't really understand that part, but maybe b/c I didn't really read the manual, just sorta looked at the pictures..

Doing a submersion bath is pretty much the way to gaurantee you don't get air bubbles in it (just gotta cycle it a ton). Its messier but it will work.

 

[captainspauldin]

Doing a submersion bath is pretty much the way to gaurantee you don't get air bubbles in it (just gotta cycle it a ton). Its messier but it will work.

yeah, so basically instead of using the bleed syringe, submerge it? Just wanna make sure I'm on the same page, just took a look at the service manual and that's my best guess.

 

[skatetokil]

I weigh like 195 in gear FWIW.

But yeah, the idea of adding slightly more damping all around makes sense. It seems like a delicate balancing act between stability and agility to find the sweet spot.

 

[Kanye West]

Fox uses Torco RSF. Progressive and Manitou use Maxima if I remember right. Marzocchi uses PC. CC uses Ohlins "5w" and I have no experience with that one - totally different kind of shock anyway. Avalanche uses Maxima. RockShox also uses Torco. Absolutely no idea on the BOS either and I gotta admit I'm curious what PUSH uses. I remember hearing Torco a couple years ago but I've also seen bottles of Maxima in some of the photos/videos of their place...

Keep in mind, Torco rebadges their fluids with a TOTALLY different set of weights just for RockShox - why, I don't know. I'll look up the numbers later, but I remember that the viscosities for the RSF's in all those were right in the ballpark of 17-21 cSt @ 40C, with the exception of the CCDB.

I've tried heavier and lighter oil in DHX's, Roco's, and Swinger/5th's. Really minimal benefit unless you like having no damping and want to just ride on the spring. Totally messes with your compression range as well. In order of effect on the shock, USUALLY changes in oil weight > porting > shim shuffling. My results with heavier oil and opening up the ports a bit more have been positive though.


For bleeding, the submersion bleed is a guarantee, but it's also expensive to get a full bucket of the nice oil, and it can foul really quickly. It's messy as hell too. If you pay good attention to their bench bleed instructions, you can do it that way instead. I've got my own methods for that, but their walk-through is a good start. It would be really sweet if those bleed ports shared the same threads as those on an Avid bleed syringe though!!

 

[JohnnyC]

yeah, so basically instead of using the bleed syringe, submerge it? Just wanna make sure I'm on the same page, just took a look at the service manual and that's my best guess.

You can bleed them just as well without any tools at all, fill the shock body up with oil and you can use the piston as a plunger to push air through the valving and out the reservoir. Use the plug in the IFP to let air out from under it when you put that in too. Plunging the IFP to the bottom can help push out any air trapped the other way too.

You can even use the squishy part of your hand to kind of "burp" most of the air out as well. Oil baths just seem like a big waste of oil.

 

[JohnnyC]

Fox uses Torco RSF. Progressive and Manitou use Maxima if I remember right. Marzocchi uses PC. CC uses Ohlins "5w" and I have no experience with that one - totally different kind of shock anyway. Avalanche uses Maxima. RockShox also uses Torco. Absolutely no idea on the BOS either and I gotta admit I'm curious what PUSH uses. I remember hearing Torco a couple years ago but I've also seen bottles of Maxima in some of the photos/videos of their place...

Keep in mind, Torco rebadges their fluids with a TOTALLY different set of weights just for RockShox - why, I don't know. I'll look up the numbers later, but I remember that the viscosities for the RSF's in all those were right in the ballpark of 17-21 cSt @ 40C, with the exception of the CCDB.

I've tried heavier and lighter oil in DHX's, Roco's, and Swinger/5th's. Really minimal benefit unless you like having no damping and want to just ride on the spring. Totally messes with your compression range as well. In order of effect on the shock, USUALLY changes in oil weight > porting > shim shuffling. My results with heavier oil and opening up the ports a bit more have been positive though.


For bleeding, the submersion bleed is a guarantee, but it's also expensive to get a full bucket of the nice oil, and it can foul really quickly. It's messy as hell too. If you pay good attention to their bench bleed instructions, you can do it that way instead. I've got my own methods for that, but their walk-through is a good start. It would be really sweet if those bleed ports shared the same threads as those on an Avid bleed syringe though!!

Fox USED to use Torco but since 07 it is Silkolene 10w. I use 5w Silkolene in Roco's and it works well

 

[captainspauldin]

It would be really sweet if those bleed ports shared the same threads as those on an Avid bleed syringe though!!

ugh, that would have made life much easier..

 

[Kanye West]

Fox USED to use Torco but since 07 it is Silkolene 10w. I use 5w Silkolene in Roco's and it works well

That's interesting. You sure that's what they use in the rear shocks? I only ask because Silkolene's 10w RSF is basically twice the viscosity of the other common RSF's (47 cSt). I've taken apart the new DHX's, and the old finger test tells me it wasn't anything that heavy.

 

[Udi]

bla bla

You won't find the numbers for every shock, which is why I said what I did. Just trust me on this one, there's enough variation between shocks that it's NOT the same (it was, and still is incorrect to say that).

Even for say Fox (which is probably one of the few shocks you'll find tangible data for), the oil they use has changed over the years - they are supposed to use Torco RSF medium (it only comes in light and medium), and while the earlier DHX's used the purple "medium", I have seen red fluid in some of the later shocks (lines up with JohnnyC's suggestion of silkolene 10 - a relatively thick oil @ 47cSt)

Take BOS as another example, they use a proprietary fluid which they don't disclose information on, so again, it could be anything.

It's always going to be hit and miss unless you are going to pull apart each shock and test the fluid yourself, which is why I said, if you aren't 100% sure on the stock fluid's specs - either find out what it is and match it, or refill with an oil you know the specs of (choose something fairly neutral like silkolene 5wt) and tune from there.

 

[Kanye West]

Yes almost all the DHX's I've pulled apart have been a red fluid (if it isn't fouled black that is). While that part agrees with the suggestion that it's the Silkolene 10w, the basic feel of it does not.

Example: putting Maxima 10w RSF in a DHX that the red fluid came out of made the damping SUPER heavy. The Maxima is 29 cSt. Definitely heavier than what was in it before.

I've done enough of these shocks to know what weight oils are going to be functional. They're basically all in the same range. No one shock except for maybe the BOS or CCDB are going to require some outlandish weight to work right. In order for any of them to function with super heavy or super light oil, they would need some major port re-sizing to achieve the same range. With the size limitations given by mountain bikes, they all arrived at more or less the same arrangement for a reason.

 

[Udi]

SUPER heavy

They're basically all in the same range.

some outlandish weight

super heavy or super light oil

Very quantitative properties there. But keep digging, this is great!

 

[Kanye West]

Your opinion is wrong, sorry to say.

If you want to provide anything useful to the discussion you may start at anytime, but you're finding yourself closer and closer to the ignore list.

 

[gemini2k]

Very quantitative properties there. But keep digging, this is great!

Your opinion is wrong, sorry to say.

If you want to provide anything useful to the discussion you may start at anytime, but you're finding yourself closer and closer to the ignore list.

Oooh, this is getting exciting, I always love e-p*nis fights. I'd better get some popcorn

 

[slowmtb]

A little off topic here, but what do you guys think of charging your shocks with Nitrogen?
This is what we did with Moto shocks and also Air shocks on our Rock Crawlers. It does not seem to mentioned very often when talking MTB shocks / forks.

Thoughts?

 

[Kanye West]

If you are experiencing shock fade, an ACCURATE nitrogen charge might help along with fresh oil. It is said to dissipate heat more effectively through the reservoir and keep the shock running cooler. In terms of shock action it shouldn't make any difference vs. a normal air charge.

 

[Udi]

If you want to provide anything useful to the discussion you may start at anytime, but you're finding yourself closer and closer to the ignore list.

I have already provided information useful to the discussion, please see post #7. If you want to see where you were wrong, please see post #6.

You have yet to provide quantitative data to prove your claim (given in post #6), and instead, all you have managed to do is make yourself look incredibly stupid. If you want to see where that happened, please see my quotes in post #29, with reasoning in post #6 and #27.

Feel free to add me to your ignore list, it won't stop me pointing out your mistakes. Posting incredibly subjective data as fact is neither adding anything useful to the discussion nor helping anyone.

 

[Kanye West]

You seem to like forums just to argue and make yourself feel better about yourself, and you are putting far too much effort into it. Bye-bye.

 

[davep]

Just because I think it is fun......



RS does not use Torco any more they use Maxima

Nitrogen does not increase cooling in any way.

It is dry (only because it is a commercial compressed gas, preventing internal corrosion) and is a larger molecule, resulting in less off gassing through rubber seals, so it results in longer pressure check/refil intervals....

Functionally, it is 100% the same as ambient air (78% nitro).

 

[Jump Chump]

with the 2.5 wt, you actually end up with a useful range of rebound damping, not fast all the way then slows down like mad on the last few clicks.

Even after a submersion bleed with Redline 2.5, this is how my WC has always acted. Way too much rebound until the last click or two. Is this to be expected?

I'm 150 lbs, run 450lb spring, 185lbs air, riding a single-pivot SWD Crazy 8.

I've had the WC for two years, and I've never been able to get past that "jittery" feeling of too much rebound, no matter the settings.

Thanks for any suggestions.

damon

Edit: Just did a bounce test, and there's a wheezy dead spot about 4/5ths through the travel. That means there's air in the can, and I need to do a better bleed, right.

 

[dhkid]

too much rebound? normally its the other way round, ie too fast till the last few clicks of rebound.

that's a weird dead spot, normally if its air the dead spot will be at the top of the travel. there might be a possibility that you put your IFP too deep and its topping out in the reservoir.

 

[Jump Chump]

too much rebound? normally its the other way round, ie too fast till the last few clicks of rebound.

Yikes, again, confusion about rebound. Yes, I meant, too fast until the last few clicks of rebound. Basically, the rebound dampening knob does nothing until the second to last click, and then the last click, the rebound is too slow, the shock would pack up over one bump. Effectively, I have one setting for rebound.

So that's my question. Is this everyone's else's experience with the WC? If so, I won't bother trying to "fix" it.

damon

 

[Pelle]

My Roco WC is way slow in rebound, I run it all the way out on the adjuster.
If I have max rebound on the shock barely moves, totally unrideable.

Overall it also feels like there´s lots of stiction but that can be the miljons of bearings, buchings and links on my Stab too.