User Tag List

Results 1 to 19 of 19

Thread: Cartridge vs Damping Rod Forks

  1. #1
    S750WP
    has no status.
    TeePee S750WP's Avatar
    Join Date
    Jul 2002
    Location
    SGP
    Posts
    4,078
    Feedback Score
    1 (100%)
    Mentioned
    12 Post(s)
    Tagged
    0 Thread(s)

    Default



    Cartridge Forks

    I am often asked the question, "Why cartridge forks? What's so great about them?" Riders know they're better but don't know why. Let's clear the air.
    Let's say you're bopping down the road, you charge into a corner and hit the brakes, the font dives radically and the bike feels like a wallowing pig. The later on you hit a square-edge bump and it feels like your wrists are going to break. Wait a minute, First the bike was too soft, then too harsh, What gives?

    Well, perhaps the problem is your basic fork design. Internally, there are two types of forks, damping-rod and cartridge. If you have an old-style damping-rod fork, you're fighting and uphill battle (there are excellent solutions for that design but we won't get into that now).

    A damping-rod fork is fairly simple: all that happens is oil is shoved through fixed orifices. This type of damping is call "velocity-squared" damping. The faster the wheel moves vertically, the more oil is shoved through the holes.

    This is an important point. The speed of the bike is not nearly as critical as the shape of the bump. If you have 2-inch high bumps that's square-edged, the wheel has to move vertically very quickly, even at low speeds. On the other hand, if the 2-inch bump has a ramp that's 2 feet long, you can imagine that the vertical wheel velocity is much less. Now, of course, the bike speed does matter: if you double the bike speed over particular bump, you will double the vertical wheel velocity.

    If the vertical velocity is doubled, the oil-flow rate through the damping holes is doubled. The interesting thing about fluid flow through fixed orifices is that the damping resistance is not doubled but instead increase with the square of the velocity; in other words, it increase by four times.

    This situation is sometimes referred to as hydraulic lock. At some point the damping force increases so rapidly that the eintire bike defelects instad of the suspension absorbing the bump.



    The problem is that "fixed orifice" damping-rod forks are too progressive. Fixed-orifice forks have very little "low-speed" damping and a lot of "high-speed" damping (vertical wheel speed). With very little low-speed camping, the fork dives excessively, and with a lot of high-speed damping you'll get a harsh spike: the worst of both worlds.

    Another limitation is revealed during revalving. Typically, revalving a damper-rod fork involves enlarging or reducing the holes, or installing thinner- or thicker-viscosity suspension fluids (there are other solutions). This decreases or increase the damping through the entire speed ranges, to the bike is better handling the spike but will be better at handling the spike but will be even worse under hard braking, or vice versa. These changes will get you in the ballpark but almost always have compromises.

    One solution is a cartridge fork. Mechanically, most cartridge forks use bending-shim-type construction instead of fixed orifices. This means there's a damping piston with a series of shims (they look like thin washers). The shims are stacked up against the face of the piston. When the oil flows through the piston, it forces the shims to deflect away from the piston face.

    This creates damping at very low velocities. At very high wheel velocities, the shims deflect more and don't create as much high speed damping as fixed-orifice-type designs, meaning that the spike on square-edge bumps is reduced. With a cartridge fork, the damping is less progressive than with damping rods.



    An added advantage of a cartridge fork is that the damping curve can be modified, or revalved, in a much more precise manner. For example, if you need less high-speed compression damping but the low-speed is perfect, the high-speed can be modified without affecting the low-speed compression because each circuit is affected by different shims when properly set up.

    So, if your bike already has a cartridge fork, great. Inherently, the cartridge fork is headed in the right direction; it has more tunability and can be dialed in to your riding requirements and ability.

    Does this mean any cartridge fork is better than any damping-rod fork? No, that depends on the valving and setup, including spring rate and oil level. Being a savvy suspension turner requires a knowledge of advanced engineering theory, the experience of extensive testing and art. something to remember is, the best you've ridden is the best you know.

    Is there any hope for the damping-rod fork? Yes, but it takes more than a little creativity and...well, that's another story.

    Paul Thede is the creative force behind Race Tech in Pomona, California, which has been modifying and creating suspension products for the last 10 years



    --------------------------------------------------------------------------------
    Magazine: Sport Rider
    Issue : August 1994

  2. #2
    henRRy
    zx1000?
    VFR Group henRRy's Avatar
    Join Date
    May 2002
    Posts
    4,451
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    I was looking for this ...Thanks man .. Nice info...

     

     
  3. #3
    rookie517
    rookie517
    has no status.
    Edit
    Guest

    Default

    now wonder i found tis articles so familiar
    hehee

  4. #4
    buja
    buja
    has no status.
    Edit
    Guest

    Default

    whoa haha, cool man....u actually spend ur time surfing fer such stuffs, unlike most of the guys here who surf for pornie stuffs...heh

    dun lk at me !!!

  5. #5
    mutoo
    mutoo
    has no status.
    Edit
    Guest

    Default

    inverted fork is which kind of fork arhh?

  6. #6
    aiya4
    aiya4
    has no status.
    Edit
    Guest

    Default

    inverted fork is which kind of fork arhh?
    haha, the one your bike is using now la!

  7. #7
    Andy
    is gonna be at SBF Anniversary 2013 @ Scape!
    Administrator Andy's Avatar
    Join Date
    May 2002
    Location
    Behind you. I'm watching you...
    Posts
    7,241
    Feedback Score
    1 (100%)
    Mentioned
    16 Post(s)
    Tagged
    0 Thread(s)

    Default

    ya, how to check what kind of fork we are using? If there anyway we can see or check to determine whether iszit a damping rod or cartridge fork?
    Your best friend in forum :: Search ::

  8. #8
    mutoo
    mutoo
    has no status.
    Edit
    Guest

    Default


    haha, the one your bike is using now la!
    i know rvf is inverted fork but my question is inverted fork is a damping rod or cartridge fork?

  9. #9
    S750WP
    has no status.
    TeePee S750WP's Avatar
    Join Date
    Jul 2002
    Location
    SGP
    Posts
    4,078
    Feedback Score
    1 (100%)
    Mentioned
    12 Post(s)
    Tagged
    0 Thread(s)

    Default

    Mine is a damping rod, check your service manaul and see wat fork you have.

    Check this website for the original article with sketches of the difference.

    http://www.racetech.com/articles/CartridgeForks.htm

  10. #10
    ZZR-Pilot
    ZZR-Pilot
    has no status.
    Edit
    Guest

    Default

    RVF is using Cartridge fork
    Well that explains the bike's high price...

    Anyway, I keep hearing about Gold Leaf Emulators that you can retrofit on damping rod forks to emulate cartridge forks. Sort of a cheap(-ish) upgrade if you want to race damping rod forked bikes.

  11. #11
    kata_killer
    has no status.
    SBF Lacer kata_killer's Avatar
    Join Date
    Jan 2003
    Location
    West Area
    Posts
    6,268
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    But wat abt d cost???
    Honda NSR 150 SP - FT4977D (June 01 - March 03)
    Honda CBR 400 RR- FL2119U (Dec 02 - Jan 04)
    Honda CBR 929 RR - FS4382A (Feb 04 - Dec 04)
    Susuki Hayabusa 1300- FX9524Z (April 05 - Oct 05)
    Susuki Bandit400- FL3540D (Mar 03 - Dec 05)
    Honda Super 4 Spec 3 - FZ9528C (Dec 05 - Jan 07)
    Honda Walve125S - FW8025J (Aug 06 - June 07)
    Yamaha Spark135 LE - FBB4..7C (March 07 - ???)

     

     
  12. #12
    henRRy
    zx1000?
    VFR Group henRRy's Avatar
    Join Date
    May 2002
    Posts
    4,451
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    CBR R model is CATRIDGE FORK>.



  13. #13
    rookie517
    rookie517
    has no status.
    Edit
    Guest

    Default

    CBR R model is CATRIDGE FORK>.


    if it have a rebound clicker on top, it is a cartridge fork
    if it has only preload, damping rod fork

    be it USD or conventional

  14. #14
    tOngEh
    has no status.
    Class 2A tOngEh's Avatar
    Join Date
    May 2002
    Posts
    651
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    Super 4 damping rod!
    There are too many coincidences in life,
    Sometimes even a pair of parallel lines meet.

  15. #15
    TSP Racing Team
    has no status.
    Class 2B TSP Racing Team's Avatar
    Join Date
    Jan 2004
    Posts
    241
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    Originally posted by rookie517@Apr 30 2003, 05:08 PM

    if it have a rebound clicker on top, it is a cartridge fork
    if it has only preload, damping rod fork

    be it USD or conventional
    cartridge type fork can com with only the the preload on the top....

    anyway, race tech has got the fork emulator done specifically for damping rod forks. done it on a gold wing and the results were good. couple with proper spring rate, oil level, oil vicosity, it has got the charactoristic of the cartrdge fork.

    i also use other race tech products on my race bike...shock tech and tsp does all the setup for me. race tech has got some really cool stuff. go check their website at www.racetech.com. those people who have them in singapore are, shock tech suspensions, sporting motorcycles, teck tai, teo spray, unity...... go to tis ppl, they'll give you proper advise....

  16. #16
    The_Sheriff
    has no status.
    Class 2A The_Sheriff's Avatar
    Join Date
    Sep 2002
    Location
    East side
    Posts
    743
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    Originally posted by henRRy@Mar 23 2003, 12:39 AM
    CBR R model is CATRIDGE FORK>.


    Only the Fireblade CBR 4000 RRR model is the catridge type. The rest of the CBR400; L, N, an Hurricane series are the damping type.

    Be happy always :-)
    Ride alert at all times

    1st bike - Yamaha RXZ - 135cc
    2nd bike - Honda FireBlade series - 400cc
    3rd bike - Yamaha RXZ- 135cc
    4th bike - Suzuki GSXR K-series - 600cc
    5th bike - Kawasaki KRR - 150cc
    6th bike - Honda CBX Twister - 250cc
    ~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~

  17. #17
    Non Stop Racing
    im the only one who can walk on both worlds - im Ghostrider
    TeePee Non Stop Racing's Avatar
    Join Date
    Jun 2003
    Posts
    2,729
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    eh it be good if any expert here can list out the kind of forks of 2b 2a class 2 bikes and show a list out

    eg sp- bah bah fork.

    s4- dam fork
    cbr-dam fork
    rvf -cart

    etc etc . any ?
    'R6' RedlineRocketRedesignRazor sharpRevolutionaryReward 6.

  18. #18
    TooToo`7
    has no status.
    SBF Lacer TooToo`7's Avatar
    Join Date
    Jan 2003
    Location
    IMH
    Posts
    7,119
    Feedback Score
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default

    Originally posted by Non Stop Racing@Apr 29 2004, 01:05 AM
    eh it be good if any expert here can list out the kind of forks of 2b 2a class 2 bikes and show a list out

    eg sp- bah bah fork.

    s4- dam fork
    cbr-dam fork, cartridge fork (R models)
    rvf -cart

    etc etc . any ?

  19. #19
    quatryu
    quatryu
    has no status.
    Edit
    Guest

    Default

    I accepth with information:
    The problem is that "fixed orifice" damping-rod forks are too progressive. Fixed-orifice forks have very little "low-speed" damping and a lot of "high-speed" damping (vertical wheel speed). With very little low-speed camping, the fork dives excessively, and with a lot of high-speed damping you'll get a harsh spike: the worst of both worlds.

    Another limitation is revealed during revalving. Typically, revalving a damper-rod fork involves enlarging or reducing the holes, or installing thinner- or thicker-viscosity suspension fluids (there are other solutions). This decreases or increase the damping through the entire speed ranges, to the bike is better handling the spike but will be better at handling the spike but will be even worse under hard braking, or vice versa. These changes will get you in the ballpark but almost always have compromises.

    __________________
    Taux simulation de prets immo bancaire | Credit simulateur de pret personnel | Simulateur de pret immobilier gratuit

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •