Maybe I didn't call them by correct name. The blue things.. (DDC's "defective Disc Components" ) are what I'm referring to. What are those blue things, and just what are they?
The DDC's are a device that takes over the damping from the stock damper rod orifices. The DDC's and Intiminators do this by using a lighter weight oil which has minimal restriction through the stock damper rod holes; the Racetech Cartridge Emulators use a heavier oil so to bypass the damper rods you drill them out to a larger size which effectively eliminates the damper rod compression function. The difference between these two approaches is why the RT Emulators are harder to install and can't be removed.
As to the why damper rods and the cartridge style devices are different; they use a different means of damping. In the case of the DDC's they use a series of deflective disks over fixed ports for compression damping and a spring poppet assy for rebound. The defective discs are the same technology used in a modern shock and offer adjustable, variable and far more compliant damping than the more progressive effects of the damper rods. by progressive, I mean that the damper rods are too progressive; what you really want is digressive which dials down the damping on high speed impacts. The overly progressive damper rods are mushy at low speed (fork action not mph!) and harsh at high speed; all because the damping is directly related to the velocity of the fork oil through the fixed openings. Conversely the discs in the DDC's open more in response to a high speed impact, thereby lessening the damping and creating a different (digressive) damping curve.....and the selection of the discs determines the shape of the curve.
The limitations of the damper rods is one of the reasons people install progressive springs in their forks in an attempt to maintain initial plushness and increase bottoming resistance and while this works to a point, it's a poor alternative to having proper modern damping curve and using the right straight or dual rate springs.
The damper rod forks in our bikes take their technology straight from the stone age; all modern offroad bikes and most higher end motorcycles use a cartridge fork. The cartridge fork uses the same type of deflective disk technology that the Cogent DDC's do. The only reason our bikes come with damper rod forks is because of cost. The single biggest functional change you can make to your KLR is suspension upgrades; from the damper rod forks and emulsion shock to a proper damping cartridge and a quality DeCarbon style shock.
In case my response isn't technical enough; Damping Rod Forks
I've also done a little write up of the differences between the DDC's and RT Emulators if you're interested.
As far as functionality goes;
- #1) Cogent DDC's
- #2) RT Emulators
- #3) Ricor Intiminators
- #4) Progressive Monotubes.....though there is a fair gap between #3 and #4
- #5) Progressive springs and heavier oil - the typical KLR "go to" bandaid
Hope this helps, feel free to ask my anything you're not clear on as KLR suspension is a bit of a passion of mine.