Are you looking to understand the physical differences in layout/function, the conceptual differences, or how the two affect real world performance?
I've read Cane Creek's pamphlet on the "Double Barrel" which had some graphics and kind of understand the idea, but not enough to understand how it would actually effect a real world riding scenario
It seems the DB setup allows more control of the oil flow using the adjusters, whereas 'de carbon' shocks have a very limited adjustment range as the adjusters account for a very small amount of the oil flow going through the piston. I also read something about DB shocks recirculating oil.
What I am having problems understanding is if the DB shock just allows a better initial setup for a specific frame(which could be achieved on de carbon shocks using a shim-stack rebuild or whatever other trickery is involved)
Or is the DB just physically a superior shock because of the way it works when dealing with the real terrain?
Any information you could provide without getting too technical (I don't mind reading tech stuff..I enjoy it! but don't want to waste your time) would be appreciated
The CCDB has 3 main selling points:
1. It's very adjustable - with separate (I avoid the term "independent" because it just isn't accurate, all HS/LS adjusters have overlap) high speed and low speed adjusters for both compression and rebound, all of which have a fairly wide range, it does work well off the shelf on a wide variety of bikes. Cane Creek also give pretty good starting points for their damper settings for almost any bike on the market, and the adjustments are consistent and precise.
2. Cavitation is almost impossible within this damper. Because oil reaches the back side of the piston both through the main piston's ports/shim stack, and simultaneously through the adjusters, cavitation can't really occur if the shock is functioning correctly (correct nitrogen pressure, standard valving etc). However, this is a fairly theoretical advantage since cavitation is actually very rare in the other high end De Carbon dampers on the market.
3. Because it has no Boost Valve or any kind of platform setting (bar the CCDBA with the Climb Switch), and it has a very small chrome plated shaft, friction is very low.
However, there are a few things worth noting:
1. The CCDB also has highly digressive compression and rebound curves. This means lots of low speed damping with proportionally less high speed damping. Regardless of what you do, this is what you'll have to some degree. For compression it is pretty well unanimously agreed upon that a digressive damper curve is a good thing, otherwise you end up with nowhere near enough LSC and way too much HSC. However, the rebound curve involved much slower LSR than most other shocks on the market - Fox for example are pretty well dead linear across the board, Elka/MRP use a very progressive rebound curve (which I personally am quite a fan of on a DH bike), which means lots of high-speed rebound damping with fairly open and free moving low speed rebound, and BOS use various curve shapes depending on application.
2. The claim that you can't get as wide an adjustment range out of a De Carbon shock is a fallacy - the adjusters simply run smaller ports and/or heavier valving if less oil is being displaced through them. However, no other shocks on the market attempt to be the one-size-fits-all shock that the CCDB tries to be, every other shock I can think of is available with multiple tunes, and as a result the range of adjustment usually doesn't need to be as wide. Keep in mind that a wide range of adjustment typically also means a lot of the range is not usable for you, and that a narrower, entirely usable range of adjustment can be more useful.
3. The CCDB is a strictly speed-sensitive shock. On certain frames, it's absolutely brilliant, but on any frame that lacks sufficient ramp up you'll be making a lot of use of the bottom out bumper unless you spring it quite stiff. Singlepivots, Demos etc aren't an ideal match for the CCDB coil for that reason, at least in this part of the world where seriously big hits are so frequent.
4. The layout configuration of your shock (twin tube, De Carbon, inline, whatever) does not dictate the characteristics of the damping curves (and thus on-trail performance) that you get from your shock. Within reason, pretty well any curve can be generated by any style of shock - the parameters that directly control the generation of pressure and thus force within the shock (valving, port dimensions, shaft diameter, bore diameters etc) are what dictate the way the damper behaves.
What this basically brings us to is that the CCDB is a very good damper, in the right frame, but that the twin-tube design, whilst technically excellent, doesn't offer the inherent and noticeable benefits that marketing departments would have you believe. Real world performance in modern DH shocks is primarily determined by the actual damping curve that the damper is generating, and as mentioned before, that isn't directly related to the layout of the damper. As with all things suspension, the devil is in the details - but details are very, very hard to market!