Suspension Component Technology/Functionality Discussion

Not exactly related to oil paths on the charger but how do we feel about the change in how compression clicks are counted on this generation of RS? My understanding is that the compression clicks start in the middle of the damping range and damping is either added or removed rather than the more common (proper) way of counting clicks from closed. It seems like this just makes it harder for the average consumer to understand where they should be counting from. Personally, it would be nice if press releases would also explain how one should start with the setup process rather than relegating it to a owners manual that many will never read. 

A prime example is a co-worker (grom who shreds) setup his Charger 2.1 with the compression fully closed as Norco's ride aligned (which is a great resource) doesn't explain how to count clicks. This lead to a fully closed compression damper rather than fully open as was intended. Makes me wonder how many peoples base settings are horrid due to this misunderstanding.

It's pretty confusing, I get where they were coming from but so far it mostly just messes with their heads. Also so many people just wind everything open anyway they aren't even looking at the markings. I like numbering the rebound dials though, that works well! 

Related to this, and your co-worker - I agree and believe it. People treat dials like they can only turn one way, and have literally had riders worried that their rebound is fully open and it still feels super slow.....because it was wound fully closed and never considered turning it the other way! 

Which brings me to another technology thing - I really want electronics to takeoff in bicycle suspension! It doesn't even have to be a full-on active FRIC system, but it could have stuff like absolute position encoders on the dials that tell you exactly where your settings are without having to even look at it or count them yourself. A tech could even check it remotely through the customer app. Going back to that last paragraph, I have seen a very non-zero number of people unbolt their suspension and ship it across the country to find out the only problem they had was the adjuster was wound fully the wrong way! You could troubleshoot set up problems remotely at a glance and not be worried that someone hasn't understood your instructions to count from fully closed.....

you can also have the problem, with the first generation of Grip2 forks where the first ~15 clicks did literally nothing on the Low speed compression (no preload) Hence counting from Open is totally redundant in a sense.

I don't know much about the mondraker system, but does it count clicks at all? Or is like a shockwiz with suggestions.

I’m torn on the electronics but what you’ve posed is super interesting. Knowing the settings remotely and being able to adjust them would be absolutely awesome for customers.

almost anytime I discuss suspension upgrades with customers they just want “better”. Almost no one can describe what their issue is nor do they know where their settings/sag is it. I guess at the end of the day more money in the till is nice but most of the time setting sag, rebound and ensuring volume spacers make sense could make people’s ride experience miles better. 

I've said it before, and I'll say it again "factory" or products with the ability to dial in High and Low speed rebound and compression are a waste on 90% of riders, most people get it so wrong they make their "superior" suspension product worse than something with good old LSR/LSC adjustment. Be it they don't know what the clickers does, or care for that matter.

I'd argue it's more like 98 or 99% of riders

HBO on the new RS SD coil is awesome, in the right situation it fires the adjuster and the oil straight out the top of it.

Never count clicks from open, always count from fully closed.

Especially important for rebound. Part tolerance and shim stack height can effect the total number of clicks, but counting from closed will always give you a number that can be referenced between shocks (at least of the same type).

For example, the Fox Float X can have a maximum of 18 clicks of rebound before the dial just keeps spinning. Stock is supposed to be 16 clicks, I have seen some with 13 clicks.

8 clicks "from open" on these three examples would result in very different rebound settings, while 8 from closed would be identical.

Care to elaborate? 

Does anyone have pictures on how Ohlins does their variable clamp shim? Digging around and have not see images of a TTX18 fully broken down.

I suspect it's similar to the Fox variable contact width leaf spring thing they us on VVC.

But if Ohlins actually changes the clamp shim diameter, that is way cooler. I have one on the DH bike that will get pulled apart sometime soon now that the snow has melted a bit. We'll see what it looks like in there!

In the TTX22 shocks this is how they describe it.

"Our first adjuster with alternate shim clamping diameters, the TTX22m compression valve enables a wide adjustment range with easy-click dial adjustment (no tools required)."

In the TTX18 cartridge.

"Öhlins forks feature a 4 position high-speed compression adjuster, providing 3 clicks of gradual compression adjustment and a fourth to use while climbing (lockout) utilising our variable clamp design."

There is a quote from Steve at Vorsprung in the NSMB article and a picture but doesn't show the mechanism of how it works.

 The variable diameter clamp system basically stiffens or softens the shim stack, and when it reaches the firmest position it also closes off the LSC circuit. It's a very good system in the sense that it allows for you to "revalve" the compression damping in a very similar way to a softer or stiffer shim stack. – Steve 

The clamp is oval shaped and the piston has 2 ports so when the clamp is 90 degrees to the ports it has a small clamp/long lever, and then turning the adjuster makes it sit lengthways across the ports to increase the clamp diameter. Clever design, and I prefer it to the fox VVC as it is much less sensitive to tolerance differences and doesn't add any non-standard valves (eg the leaf springs on a VVC damper)

Couple of photos of the fork version in soft and hard positions-

https://www.instagram.com/p/Bu-bf1GF2Yg/?utm_source=ig_web_copy_link

And you can see the adjuster on the picture from above-

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Thanks for sharing. I have been going down the rabbit hole of learning the inner works of Ohlins stuff after recently purchasing an RFX36. 

Hey peanut gallery, any tips or advice for setting up a three chamber air system on a fork?

I have the chance to ride one of the new Ohlins RXF.38 m.2 forks soon with the dual positive chamber air spring, but I've never ridden a three-chamber fork like the Ohlins, Manitou, EXT, DSD Runt, etc and I really have no idea what the secret is. I know I like a very stiff air spring that's fairly middle of the road in progression- not super progressive like a fork packed with the max number of volume reducers. Does that mean I'll want my two positive chambers to be fairly similar in pressure? Asking because I really have no idea.

The second or ramp chamber (inflate it first) should be about 150-200% of the main chamber. I like to think of it as starting off with a fork with max tokens, so you get the best positive to negative chamber ratio in the beginning to mid stroke. Then somewhere in the mid stroke as the main and secondary chambers equalize in pressure and the secondary piston starts to move into the secondary chamber and away from the main chamber, it's like making tokens magically disappear so you can fine tune the spring ramp deep in the travel. It's a much better air spring system, I think. Most of my riding is a series of winch and drops and it allows me to run a much more linear spring rate than I could normally get away with and just use the 3 position high speed damper for the next section of trail, more open for chatter, more closed for big compressions.

Running the same pressures should make it feel like a single positive chamber fork with no tokens. The higher the difference in pressures, the more it will feel like you have a lot of tokens in the first part of the travel and later the 'blow-off' will happen compared to a full token setup. You need to reach the third chamber pressure inside the main positive chamber for the floating piston to start moving and changing the main positive chamber volume.

A triple chamber fork should never feel like a single positive chamber fork except in the two situations where you have no tokens or as many tokens in volume as the third chamber takes up. In reality the spring characteristic should be somewhere in between the two extremes. 

A larger difference in pressures will make it firmer in the initial part of the stroke, making the second chamber engage later in the travel, like the tokens being removed as has been mentioned. So it’s kind of backwards to how you might initially think of it! The larger difference is more like a linear spring than a typical air spring as it’s firmer in the beginning and softer at the end

Yep, that's where I found the sweet spot for me. I find the fork less comfortable and more prone to beating my hands up in the rough stuff when I run the recommended air pressure in the ramp up chamber. I'm usually at 10-20% below the recommended values in the ramp up chamber, and then I just dial in the base spring pressure with the main air chamber until sag/ride height/travel use goals are reached. A couple of clicks of low-speed compression when it gets steeper, and I can still get away with running a bit less in the main spring than recommended too (YMMV depending on terrain/speed/radness of rider). BTW in a fork with tokens, my goal is always to run as few tokens as possible, which is basically the same thing as lowering the pressure in the ramp up chamber. IMO, a fork is most comfortable when it works in the less steep part of the spring rate curve, this is more important to me than having a spring rate which is artificially low in the beginning of travel and then spikes like mad because of a bunch of tokens.

These recommendations from an essentially over-the-hill hack journo...if I was sending that drop to flat in Loudenvielle on a regular basis I have no doubt I'd need a bit more in there... ;-)

The Ohlins 3 chamber air spring is very different from say a DSD RUNT in a Fox fork.

The Runt has a similar size piston to the main air spring, where as in the Ohlins fork the 3rd air chamber and piston are tiny. It is inside the shaft for the air spring. Probably how they got around the Runt patents.

It works, but is less effective and less "tunable" than a system with a larger 3rd chamber piston. If usually requires much higher pressures to do anything (since the piston is so small). I have an Ohlins DH 38 as well as multiple Fox and RS forks with Runts installed. Runt preferred by far.

But setup is all the same. Air the 3rd chamber up first to 150 psi or more. Then set the main air chamber pressure to get the feel off the top and sag you like. Then go back and double that pressure in the 3rd chamber.

If you want more late-mid stroke hold up and end of travel support, increase the pressure in the 3rd chamber. If you want to get more travel and a more linear feel, decrease the pressure in the 3rd chamber. But keep the main chamber the same. For how @TEAMROBOT describes his preferred fork setup, yes the pressures will be closer than typical. Probably less than double in the 3rd chamber. Sounds like he likes a stiff linear setup.

A real benefit of the Runt is that is allows for lower main chamber pressures for better small bump and sensitivity (like cramming the fork full of volume spacers), but then has tunable progression without a massive ramp.

DSD has a good animation on function;

Not really how three chamber air springs typically work or how you set them up.

A fork with 50psi in main and 150 psi in 2nd positive chamber will definitely not feel firmer initially than a fork with 50 psi in main and 100 psi in the 2nd chamber.

They will feel the same initially, the 50/150 fork will then have a steeper ramp like a typical air spring. The 50/100 fork will have a more moderate ramp, more linear.

The 2nd positive chamber is mostly a tuning aid for the last 3rd of travel due to the much smaller volume and higher pressure compared to the main chamber. It does not effect initial travel.

Thank you all! Super helpful info, and I think you've saved me a ton of faffing. This gives me a much better sense of where my baseline might be, or at least a better starting point than following the manual with fingers crossed and having no additional tools in my toolbox if the manual's prescribed setup doesn't work.

Yes that why I was talking in relative terms, not absolute as a general description of how they function and not brand specific. Its a glass half full/half empty kind of thing, it all depends on whether you are talking about increasing or decreasing each chamber from the baseline, but it also depends on the relative size of the chambers. Which is where you are correct in that the ohlins chamber is very small so has its effect much closer to the end of the travel. This design has been around a very long time and is usually made to work earlier in the travel so the progressive feeling is in the top half, which makes the Ohlins unique but also wonder why they don't just use a token system in that case?

Has anyone had the chance to dissect and assess EXT ERA’s air spring? They too have the triple chamber. Their setup chart seems to use a ratio of around 1.5 for the difference between main and secondary spring. Is there anyone out there doing custom work on these yet? I’m waiting for my V2.1 to arrive. I’ve been using this fork for a couple years now and for the most part have been impressed with how it handles high speed chunky stuff. Would love to know if there’s more performance to be unlocked thru custom tuning/mods

There hasn't been a lot of incentive for aftermarket tuning with the ERA - with any suspension product, friction is the crucial thing to deal with first or whatever else you try will have very little effect and EXT have already had a couple of major revisions to address this, so that's where riders need to look first. On paper the internals look quite good and probably don't need too much in the way of "special sauce" for them to function really well and its mostly been a few friction things holding it back. Those aren't always quite as simple for a tuner to resolve, especially when the manufacturer is already rolling out an update. 

Maybe in time there will be the opportunity for damper tuning with them, but until people get more time on the V2.1 versions I wouldn't expect there to be many options. 

Mentioning the air pressure ratio is an interesting point though - that kind of indicates the intended function and proportion of air chamber sizes. Since the second chamber begins moving once the pressures are equal, a smaller ratio like 1.5 suggests it will begin moving early in the stroke, like before 1/2 of the way through. Because in an air spring as the chamber volume halves, the pressure doubles. Obviously the chambers will be longer than the travel of the fork, so you would still need the dimensions of the springs to have an idea of when those transitions are actually happening. Still a useful way to wrap your head around it IMO.

That reminds me though I think I have the measurements of an ERA spring somewhere, I think I did actually measure it all up at one point when it first came out. It has changed since then though and I haven't had a chance to work on the new version 

“Mentioning the air pressure ratio is an interesting point though - that kind of indicates the intended function and proportion of air chamber sizes. Since the second chamber begins moving once the pressures are equal, a smaller ratio like 1.5 suggests it will begin moving early in the stroke, like before 1/2 of the way through. Because in an air spring as the chamber volume halves, the pressure doubles. Obviously the chambers will be longer than the travel of the fork, so you would still need the dimensions of the springs to have an idea of when those transitions are actually happening. Still a useful way to wrap your head around it IMO.”

👆🏻 This for me is the crucial factor in why a triple chamber fork will always perform differently to a typical fork with tokens…

even if the chambers are set to the same pressures, because of the smaller size of the ramp chamber, it’s pressure builds faster than the main chamber, so they will never compress proportionally the same as a normal positive chamber without tokens.

depending on the ratios of the air chambers as well, as you say, you can get the bottom out chamber to start moving earlier in the travel and have a completely different effect on the spring curve than if you just have a smaller high pressure chamber that would be used primarily for bottom out control.

Is the next level in fork tuning a triple chamber spring with tokens in the third chamber? 

Obviously you can play with oil/grease volumes in either chamber to your hearts content. And you get added benefit of better lubrication you don't with the volume reducers.

Why stop at the third chamber? You could make tokens for all 3!! 

I really hope no-one does that though......I'm personally not a fan of multiple chambers because of the complexity ever since Marzocchi first introduced them around 2006 or 7. I was the local service tech a little after that so we were still selling them, and trying to help people through pumping up 3 air valves (sometimes 4 or 5, I AM NOT KIDDING) was punishing! There is no simple "set and forget" way of tuning them as every time you pump it up or check pressure it needs to be in a specific order or the chambers would be all over the place. 

For sure they can work better than a single positive chamber, but the amount of time and effort it takes to get there is just too difficult when you still have things like friction compromising performance.