[CraigS]

Been riding a 2013 Demo for about a year now and have the rear shock setup using Cane Creeks recommended tune from there site.
I recently rode some trails that had some high speed square edge hits that spiked and kicked the rear end that I never experienced with the bike before.
So my first response would be to decrease the HSC.
My question is, will I need to decrease HSR as well? or am I way off and should do something else.

I haven't changed anything from the base tune as of yet, I rode the rest of the day with my current setup.

some numbers................about 175lbs geared up with a 400lb ti spring and about 25% sag.
Front fork is a Fox 40 Float with about 60psi set at the most linear.

 

[Jm_]

I'm curious about this as well. Nearly every person I inquire about this with when I'm at the local DH mountain mentions the same thing. I'm in the market for a new shock and the CCDB is one of the few that fits, but definitely not the only one that fits, and I might go for it if it's worth it. I have some time on it, but not enough to really make the high-speed determination.

Here's what worries me:

It's a poppet valve controlled by a spring. This is inherently linear spring. Thespring on the low-speed compression should be stronger and provide more resistance, as low-speed displacement is simply slower and doesn't try to move fluid as fast. The high-speed poppet, backed by a spring, will try to move as the fluid pushes against it, the more it pushes, the more it moves, but the "damping curve" is fixed.

This is not like the curve you get with a shimmed compression valve. There you have wide shims offering little resistance so oil starts flowing easily on a high-speed impact, but you can also back it up with heavier shims closer to the center which will add more resistance as the speed of the fluid increases. It seems that you could tune the high speed in this case to "open" fairly easily, but still resist bottomout as the flow increases significantly. This doesn't seem possible on the CCDB, you'd have to crank down the high speed to get that end result, but it will also prevent the circuit from opening as easily. In other words, you could have far more tuning options with a shimmed piston.

The CCDB does have a shimmed piston, made clear after their initial propaganda that the fluid only flows one way and that it didn't need one, but it remains an non-tunable parameter and a very heavy stack/restricted piston.

Thoughts?

 

[Steve M]

Been riding a 2013 Demo for about a year now and have the rear shock setup using Cane Creeks recommended tune from there site.
I recently rode some trails that had some high speed square edge hits that spiked and kicked the rear end that I never experienced with the bike before.
So my first response would be to decrease the HSC.
My question is, will I need to decrease HSR as well? or am I way off and should do something else.

I haven't changed anything from the base tune as of yet, I rode the rest of the day with my current setup.

some numbers................about 175lbs geared up with a 400lb ti spring and about 25% sag.
Front fork is a Fox 40 Float with about 60psi set at the most linear.

If you're having issues with single sharp hits causing a spiking feeling, decreasing HSC will have the biggest effect. There should be no need to alter your rebound settings unless the harshness is coming from packing down of the suspension. Reduce HSC quarter of a turn at a time and see how you go.

I'm curious about this as well. Nearly every person I inquire about this with when I'm at the local DH mountain mentions the same thing. I'm in the market for a new shock and the CCDB is one of the few that fits, but definitely not the only one that fits, and I might go for it if it's worth it. I have some time on it, but not enough to really make the high-speed determination.

Here's what worries me:

It's a poppet valve controlled by a spring. This is inherently linear spring. Thespring on the low-speed compression should be stronger and provide more resistance, as low-speed displacement is simply slower and doesn't try to move fluid as fast. The high-speed poppet, backed by a spring, will try to move as the fluid pushes against it, the more it pushes, the more it moves, but the "damping curve" is fixed.

This is not like the curve you get with a shimmed compression valve. There you have wide shims offering little resistance so oil starts flowing easily on a high-speed impact, but you can also back it up with heavier shims closer to the center which will add more resistance as the speed of the fluid increases. It seems that you could tune the high speed in this case to "open" fairly easily, but still resist bottomout as the flow increases significantly. This doesn't seem possible on the CCDB, you'd have to crank down the high speed to get that end result, but it will also prevent the circuit from opening as easily. In other words, you could have far more tuning options with a shimmed piston.

The CCDB does have a shimmed piston, made clear after their initial propaganda that the fluid only flows one way and that it didn't need one, but it remains an non-tunable parameter and a very heavy stack/restricted piston.

Thoughts?

There is no spring on the low speed compression circuit, it's a needle/orifice system like everything else. The HS poppet valves provide for a very digressive curve, and are in this case necessary as the volume flow rate through the HS circuits is high. The HS damping rate is pretty well dead linear once open, which is the same as a preloaded shim stack. If you consider the shim stack on the CCDB to be a non-tunable parameter then presumably you also consider the shim stacks on any other shock to be equally non-tunable, so it's a moot point.

 

[Jm_]

If you're having issues with single sharp hits causing a spiking feeling, decreasing HSC will have the biggest effect. There should be no need to alter your rebound settings unless the harshness is coming from packing down of the suspension. Reduce HSC quarter of a turn at a time and see how you go.



There is no spring on the low speed compression circuit, it's a needle/orifice system like everything else. The HS poppet valves provide for a very digressive curve, and are in this case necessary as the volume flow rate through the HS circuits is high. The HS damping rate is pretty well dead linear once open, which is the same as a preloaded shim stack. If you consider the shim stack on the CCDB to be a non-tunable parameter then presumably you also consider the shim stacks on any other shock to be equally non-tunable, so it's a moot point.

Doesn't change my point, the "curve" is based on the high speed poppet, according to CC this does the majority of the high speed damping, which lessens your tuning capability significantly, adding to that is the fact that the in-line and/or external res air model still have a heavy flat washer on the rebound side of the piston.

 

[ZoRo]

Everytime I see a DB post, I think of this https://trivialmtb.wordpress.com/2014/10/14/is-no-one-going-to-say-this/

 

[Dogboy]

Everytime I see a DB post, I think of this https://trivialmtb.wordpress.com/2014/10/14/is-no-one-going-to-say-this/

Yeah, that's pretty stupid.

 

[Beef Supreme]

If you're having issues with single sharp hits causing a spiking feeling, decreasing HSC will have the biggest effect. There should be no need to alter your rebound settings unless the harshness is coming from packing down of the suspension. Reduce HSC quarter of a turn at a time and see how you go.

I don't normally try to clarify the comments of people that know way more than I do. In this case I am betting it is the HSR setting. The OP should notice too much HSC under a broader range of situations. It sounds like he found terrain that is causing the suspension to pack since it is rare. Back the HSR off a bit and ride the same section to test.

 

[frorider]

as an owner of two CC shocks (coil, and the inline), I agree w/ Beef S.

 

[Steve M]

Doesn't change my point, the "curve" is based on the high speed poppet, according to CC this does the majority of the high speed damping, which lessens your tuning capability significantly, adding to that is the fact that the in-line and/or external res air model still have a heavy flat washer on the rebound side of the piston.

When you close down the HSC adjuster, it forces more oil through the main shim stack. As pressure difference (and therefore damping force) is a function of volumetric flow rate, the more oil being forced through the main stack, the steeper the damping curve. Admittedly, in practice the increase is relatively small - from a purely mathematical standpoint it's not perfect, but in practical terms it's solid.

The rebound damping in those is rarely the issue, and the point stands - if you're willing to revalve any other shock, you can do the same to the compression circuit in the CCDB and change the shape of the curve. If the HS support is insufficient, you can change the spring for one with a stiffer rate and run less preload. None of this is impossible or even difficult to do in the context of shock valving. If we're talking about what you can achieve from stock using purely external adjustments, the DB damper still beats pretty well anything else. The air spring is another matter.

I don't normally try to clarify the comments of people that know way more than I do. In this case I am betting it is the HSR setting. The OP should notice too much HSC under a broader range of situations. It sounds like he found terrain that is causing the suspension to pack since it is rare. Back the HSR off a bit and ride the same section to test.

Entirely possible - as I said, excessive HSC will typically be noticeable on a single hit.

 

[jstuhlman]

why don't you just email CC? they're super nice.

 

[Kanye West]

. If the HS support is insufficient, you can change the spring for one with a stiffer rate and run less preload. None of this is impossible or even difficult to do in the context of shock valving..

Got one? Or at least some specs? A smoother transition to high speed support and a less aggressive mid-speed is exactly what I'm after with a DB Inline.

 

[Jm_]

When you close down the HSC adjuster, it forces more oil through the main shim stack. As pressure difference (and therefore damping force) is a function of volumetric flow rate, the more oil being forced through the main stack, the steeper the damping curve. Admittedly, in practice the increase is relatively small - from a purely mathematical standpoint it's not perfect, but in practical terms it's solid.

That's not the issue. The issue is people think the CCDB can be tuned for any bike because it has adjustments for high/low rebound and compression, when in reality, we are not adjusting a shim stack, but preload on a poppet valve, which is like adjusting preload on any kind of spring-loaded valve, poppet or shim, it just gives you more "jackhammer" effect, instead of being able to properly tune the stack. CCDB tries to market it as "adaptable to any bike" with just the adjusters.

The rebound damping in those is rarely the issue, and the point stands - if you're willing to revalve any other shock, you can do the same to the compression circuit in the CCDB and change the shape of the curve. If the HS support is insufficient, you can change the spring for one with a stiffer rate and run less preload. None of this is impossible or even difficult to do in the context of shock valving. If we're talking about what you can achieve from stock using purely external adjustments, the DB damper still beats pretty well anything else. The air spring is another matter.

Problem is all the complexities with the fluid flow, piston size, etc. It's not as simple as slapping a few shimz on there or taking them out, the shock is intended to push most of the oil through the poppets, so the pressure the piston is seeing is far different than in a conventional shock, add to that the issue of the piston orifice size, again, not necessarily apples to apples, so rather than shoot in the dark for 5 revalves, it's a little easier to start off with something revalved correctly, and then the "benefit" of the CCDB magically disappears, although it was never really there according to the first paragraph. Seems like this just goes back to the idea that a custom valved shock will always be superior, and the ability to preload the poppet valve springs is not like re-shimming a compression valve, it's like preloading a compresion valve(because that's what it is), which is why increasing the damping has more of a jack-hammer effect and why it may be hard to eliminate spiking on this shock (without figuring out the correct orifice size and stack on top).

 

[Steve M]

That's not the issue. The issue is people think the CCDB can be tuned for any bike because it has adjustments for high/low rebound and compression, when in reality, we are not adjusting a shim stack, but preload on a poppet valve, which is like adjusting preload on any kind of spring-loaded valve, poppet or shim, it just gives you more "jackhammer" effect, instead of being able to properly tune the stack. CCDB tries to market it as "adaptable to any bike" with just the adjusters.

You can't externally "adjust the shim stack" on any shock, all you can do is adjust the preload, so once again, null argument. Claiming something "just gives you more jackhammer effect" is unsubstantiated, the HS adjusters on the CC function in exactly the same way as any other HS adjuster - they increase the opening force required for the high speed valve. If you take issue with CC's approach to that, then I can only assume you think the HS adjusters made by Fox, Avalanche, Rockshox, every moto suspension manufacturer etc all suck too, because they all have the exact same effect.

Problem is all the complexities with the fluid flow, piston size, etc. It's not as simple as slapping a few shimz on there or taking them out, the shock is intended to push most of the oil through the poppets, so the pressure the piston is seeing is far different than in a conventional shock, add to that the issue of the piston orifice size, again, not necessarily apples to apples, so rather than shoot in the dark for 5 revalves, it's a little easier to start off with something revalved correctly, and then the "benefit" of the CCDB magically disappears, although it was never really there according to the first paragraph. Seems like this just goes back to the idea that a custom valved shock will always be superior, and the ability to preload the poppet valve springs is not like re-shimming a compression valve, it's like preloading a compresion valve(because that's what it is), which is why increasing the damping has more of a jack-hammer effect and why it may be hard to eliminate spiking on this shock (without figuring out the correct orifice size and stack on top).

"All the complexities with fluid flow, piston size etc" exist in every damper. Nobody in the entire MTB suspension industry uses different pistons for different applications in the same shock, so you have the same non-issues in a Fox, Rockshox, Avalanche or any other damper if you revalve them - and surprisingly, it IS about as simple as softening or stiffening the stack (if it's not, someone please call Roehrig and tell them my dyno is playing up). For some reason you seem to assume that you can revalve one shock precisely in one go, but the CCDB will take five to perform exactly the same form of tuning. The only remotely valid point is that the CCDB is only available for purchase with a single main piston tune. However even that ignores the practical reality - that you actually CAN get the damper to work very well in most applications because the range of adjustment is wide, and that with any custom valved shocks with narrower adjustment range, you rely on the valving being well optimised for you in the first place.

Could the CCDB's performance be improved upon? In some cases, substantially; in many cases, marginally; in some cases it's pretty well optimised though.

 

[Jm_]

You can't externally "adjust the shim stack" on any shock, all you can do is adjust the preload, so once again, null argument. Claiming something "just gives you more jackhammer effect" is unsubstantiated, the HS adjusters on the CC function in exactly the same way as any other HS adjuster - they increase the opening force required for the high speed valve. If you take issue with CC's approach to that, then I can only assume you think the HS adjusters made by Fox, Avalanche, Rockshox, every moto suspension manufacturer etc all suck too, because they all have the exact same effect.

No, you are putting words in my mouth. The other shocks use different shim tunes to adapt to different bikes/riders/leverage ratio. The high speed adjusters fine tune the characteristics.

The basic problem is CCDB gives you a shock and tells you it works for every bike and rider, and all you have to do is use the correct tune of the poppet valves. This is one of the selling points they use with the shock. What we are learning here is that idea is woefully inadequate, the other manufacturers do not use this idea, no matter how much you think they do. While they don't offer an unlimited gamut of tunes, they at least have different tunes depending on the application and they don't rely on a spring-preload on the valve to be the controlling factor for a tune.

 

[Steve M]

No, you are putting words in my mouth. The other shocks use different shim tunes to adapt to different bikes/riders/leverage ratio. The high speed adjusters fine tune the characteristics.

The basic problem is CCDB gives you a shock and tells you it works for every bike and rider, and all you have to do is use the correct tune of the poppet valves. This is one of the selling points they use with the shock. What we are learning here is that idea is woefully inadequate, the other manufacturers do not use this idea, no matter how much you think they do. While they don't offer an unlimited gamut of tunes, they at least have different tunes depending on the application and they don't rely on a spring-preload on the valve to be the controlling factor for a tune.

It appears that you are inventing flawed theoretical explanations for an experience you said yourself that you haven't actually had - the HSC adjusters functionally have a similar effect as changing a shim configuration because of the volume they instead force through the main shim stack (which, believe it or not, is open to some degree from a very very low speed), and let's not forget that the nose of the poppet is shimmed to provide a smoother transition between open and closed irrespective of preload. It's far from "woefully inadequate" - not perfect for certain applications, sure, but your implication that it is somehow inherently a flawed design is unjustified and unsubstantiated. In a non twin-tube shock, the flow rate through the main piston is fixed at any given velocity (unless it cavitates), so in those cases it will perform differently, with a more digressive curve.

For the record, the main reason most shocks don't use poppet valves (other than BOS) is not because of issues with the damping characteristics, but rather because of the potential for cavitation if the poppet valve preload is insufficient (which does happen with certain BOS dampers we've dyno'd). The CCDB doesn't have that issue because of its twin tube design meaning that oil doesn't need to pass through the main piston at any specific flow rate to avoid cavitation as it can replenish oil behind the piston directly from the reservoir. In fact, BOS actually changed the Stoy damper from a shimmed base valve to a poppet base valve specifically to get rid of the spiking issues they had on certain frames.

 

[tacubaya]

Sir, this jackhammer isn't breaking the concrete, should I increase shim preload?