Suspension Knowledge N00b... help please.- Mtbr.com
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  1. #1

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    Bonking ... not feelin' well Suspension Knowledge N00b... help please.

    Hey everyone.

    I am currently thinking of getting a new fork for my Sasquatch or (soon to be) Coiler.
    I am thinking either the Marz 66 Series, or the Z1 series.

    Now, the reason for this thread: I don't understand all the technical "Mumbo-Jumbo" of the different adjustments on the forks... Could someone please explain (just like you were talking to a 5 yr old) the different terms and how they affect riding? For example, the actual "rc2x"... what does that mean/ stand for?
    Also the "Lite" one?
    I've visited the Marz. website and looked but i would prefer someone to explain.

    Thanks so much, greatly appreciated!

    Cheers,
    Laurence

    :EDIT: Also, some more things i have no idea about:

    For rear Shocks how does/ what does rebound, spring preload do for riding?
    What does the "piggy-back" oil resovior(sp?) do?
    Also, what is high speed/ low speed compression?

    Sorry for all the questions, but i have searched to no avail!
    Last edited by borry; 07-15-2006 at 05:05 AM.

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  3. #3
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    Well, I'll try to....

    help you out here.

    "For example, the actual "rc2x"... what does that mean/ stand for?"

    RC2x is Zocchs accronym for the damping system in the 888 and 66 RC2x models. All it stands for is Rebound (R), Compression (C), times 2 (2x). What it is, a combination of Low speed rebound and compression damping circuits (both adjustable), and a high speed compression damping circuit which is also adjustable.

    "Also the "Lite" one?"

    I assume you are talking about the 66 Light here. There are two models that are lighter in weight than the RC2x and the VF2 models, The "Light" and the SL (Super Light). The Light saves weight by using a one side coil and one side air spring configuration and on using only the RC2 system rather than the RC2x damper. The SL is a totaly air sprung fork and saves weight over the Light in this way. Anyway, thats the way it's SUPPOSED to work, however, the Light is actually a tad heavier than the RC2x model, about 6 grams I think. The lightest of the 66 series is the SL with a "claimed weight of 2560 grams.

    "For rear Shocks how does/ what does rebound, spring preload do for riding?"

    Rebound is the same for rear shocks as it is for forks, it referes to rebound damping. And just like forks it keeps the shock from rebound to quickly and bouncing you around. Spring preload is also the same for forks and shocks. How it is accomplished is a bit different in some cases though. For most coil shocks preloading the spring is accomplished by turning the knurled ring that sits atop the coil spring clockwise. This puts pressure on the spring "preloading" it. This is used to set how much the rear suspension "sags". Sag is the amount that a fork or shock compresses while you are simply sitting on the bike. Sag allows the fork or shock to follow the terrain while you ride. In other words, with the proper amount of sag the suspension will not only soak up bumps but will also follow holes as well. This helps keep your wheels in contact with the ground as much as possible and makes for better traction. That's with a coil fork or shock, and is called "mechanical preload". With air forks or shocks there is no mechanical adjustment because the amount of air pressure is used to set preload and sag. Another function of preload is to tune the ride as well. More preload and less sag equals a stiffer ride, less preload and more sag equals a squishier ride.

    "What does the "piggy-back" oil resovior(sp?) do?"

    One of the problems with an oil damped shock became evident years ago as Down Hill racers and Freeriders got more aggressive and the courses became more technical. They started blowing the seals in their shocks. The reason being was the bigger hits, higher speeds, big drops, jumps, etc. These would build tremendous pressure in the dampers as they tried to do their job. A big enough hit and you'd blow the seals, the damper would fail.
    The solution was to put more oil in the system. To do this a piggy back resivour was added. This increased oil volume and gave the oil some place to go on big hits, gave a wider adjustment range, kept the oil cooler, and generally increased damping performance. You see them mostly on shocks designed for DH and Freeride big hit peformance.

    "Also, what is high speed/ low speed compression?"

    They are just exactly what the names state, high speed and low speed damping. This however does not refer to the speed of the bike (it can be related to speed though) but rather the speed of the compression and/or rebound of the fork or shock. Basically it refers to two DIFFERENT circuits in the damper. One effects low speed compression/rebound the most, the other affects high speed. It used to be that most forks were set up with low speed circuits as most riding involved cross country and technical riding with 80 or 100mm suspension, where compression and rebound speeds were fairly slow. But todays styles of riding and longer travel suspension systems have pushed the envelope and high speed circuits have been added to the dampers in many higher end forks and forks designed to more aggressive riding. Longer travel forks have more range of motion, thus more room to acclerate. This requires different valving to handle the extra compression and rebound speeds that are achieved and keep the bike under control. Thus the High Speed damping. But you still need low speed damping as well, because you're not always bombing down hill with your hair on fire! So manufacturers produce forks that have both high and low speed circuits in the same damper. In many instances both high and low speed circuits are independently adjustable as well.

    There's a lot more that to than what I've covered above, but in the intrest of simplicity that's pretty much it in a nut shell. What you actually need is dependent on your riding style, suspension travel, etc. If you are riding a 100mm travel bike and riding pretty much XC/Trail moderately agressively, then you don't need all them bells and whistles. But if you are riding a 150mm travel All Mountain style bike, doing drops, jumps, and love fast down hills, then the extras are a good idea. They'll impove the ride, suspension peformance, overall control over the bike, and allow for custom tunning of the suspension for the terrain being ridden.

    Hope this helps you out a bit. Not the deffinitive explanations for your questions, but the basic ideas for each.

    Good Dirt
    "I do whatever my Rice Cripsies tell me to!"

  4. #4

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    Quote Originally Posted by Squash
    help you out here.

    "For example, the actual "rc2x"... what does that mean/ stand for?"

    RC2x is Zocchs accronym for the damping system in the 888 and 66 RC2x models. All it stands for is Rebound (R), Compression (C), times 2 (2x). What it is, a combination of Low speed rebound and compression damping circuits (both adjustable), and a high speed compression damping circuit which is also adjustable.

    "Also the "Lite" one?"

    I assume you are talking about the 66 Light here. There are two models that are lighter in weight than the RC2x and the VF2 models, The "Light" and the SL (Super Light). The Light saves weight by using a one side coil and one side air spring configuration and on using only the RC2 system rather than the RC2x damper. The SL is a totaly air sprung fork and saves weight over the Light in this way. Anyway, thats the way it's SUPPOSED to work, however, the Light is actually a tad heavier than the RC2x model, about 6 grams I think. The lightest of the 66 series is the SL with a "claimed weight of 2560 grams.

    "For rear Shocks how does/ what does rebound, spring preload do for riding?"

    Rebound is the same for rear shocks as it is for forks, it referes to rebound damping. And just like forks it keeps the shock from rebound to quickly and bouncing you around. Spring preload is also the same for forks and shocks. How it is accomplished is a bit different in some cases though. For most coil shocks preloading the spring is accomplished by turning the knurled ring that sits atop the coil spring clockwise. This puts pressure on the spring "preloading" it. This is used to set how much the rear suspension "sags". Sag is the amount that a fork or shock compresses while you are simply sitting on the bike. Sag allows the fork or shock to follow the terrain while you ride. In other words, with the proper amount of sag the suspension will not only soak up bumps but will also follow holes as well. This helps keep your wheels in contact with the ground as much as possible and makes for better traction. That's with a coil fork or shock, and is called "mechanical preload". With air forks or shocks there is no mechanical adjustment because the amount of air pressure is used to set preload and sag. Another function of preload is to tune the ride as well. More preload and less sag equals a stiffer ride, less preload and more sag equals a squishier ride.

    "What does the "piggy-back" oil resovior(sp?) do?"

    One of the problems with an oil damped shock became evident years ago as Down Hill racers and Freeriders got more aggressive and the courses became more technical. They started blowing the seals in their shocks. The reason being was the bigger hits, higher speeds, big drops, jumps, etc. These would build tremendous pressure in the dampers as they tried to do their job. A big enough hit and you'd blow the seals, the damper would fail.
    The solution was to put more oil in the system. To do this a piggy back resivour was added. This increased oil volume and gave the oil some place to go on big hits, gave a wider adjustment range, kept the oil cooler, and generally increased damping performance. You see them mostly on shocks designed for DH and Freeride big hit peformance.

    "Also, what is high speed/ low speed compression?"

    They are just exactly what the names state, high speed and low speed damping. This however does not refer to the speed of the bike (it can be related to speed though) but rather the speed of the compression and/or rebound of the fork or shock. Basically it refers to two DIFFERENT circuits in the damper. One effects low speed compression/rebound the most, the other affects high speed. It used to be that most forks were set up with low speed circuits as most riding involved cross country and technical riding with 80 or 100mm suspension, where compression and rebound speeds were fairly slow. But todays styles of riding and longer travel suspension systems have pushed the envelope and high speed circuits have been added to the dampers in many higher end forks and forks designed to more aggressive riding. Longer travel forks have more range of motion, thus more room to acclerate. This requires different valving to handle the extra compression and rebound speeds that are achieved and keep the bike under control. Thus the High Speed damping. But you still need low speed damping as well, because you're not always bombing down hill with your hair on fire! So manufacturers produce forks that have both high and low speed circuits in the same damper. In many instances both high and low speed circuits are independently adjustable as well.

    There's a lot more that to than what I've covered above, but in the intrest of simplicity that's pretty much it in a nut shell. What you actually need is dependent on your riding style, suspension travel, etc. If you are riding a 100mm travel bike and riding pretty much XC/Trail moderately agressively, then you don't need all them bells and whistles. But if you are riding a 150mm travel All Mountain style bike, doing drops, jumps, and love fast down hills, then the extras are a good idea. They'll impove the ride, suspension peformance, overall control over the bike, and allow for custom tunning of the suspension for the terrain being ridden.

    Hope this helps you out a bit. Not the deffinitive explanations for your questions, but the basic ideas for each.

    Good Dirt
    Thanks so much Squash! That was a great read. If you dont mind me bugging you again can you answer some more Q's?

    With the Mrz. 66 Lite you said one side was coil and one side was air, Does only one side being Coil making the riding differ in any way?

    How would i go about tuning in the different rc2x adjustments (if i was to buy the 66 rc2x)?

    Also i noticed that the 66 lite had an ETA version... does that mean the travel is adjustable on the Marz. 66 Lite ETA?? On the manufacturers' website it just says 170mm.

    Thanks again mate.

  5. #5
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    I'll help squash out here with the 66, his weights and features aren't quite correct;

    66 RC2x;
    Left leg: high speed "x" cartridge w/coil spring and air preload.
    Right leg: RC2 cartridge w/coil spring and air preload.
    ~6.4lbs

    66 Light ETA;
    Left Leg: ETA cartridge w/coil spring.
    Right Leg: RC2 cartridge.
    ~6.5lbs

    66 SL;
    Left Leg: air cartridge with positive, negative, and PAR (bottom out resistance) air adjustments.
    Right Leg: RC2 cartridge. I'm not sure if this leg also has air preload.
    This fork also has a slightly different crown, that is machined around the stanchions to make it slightly lighter.
    Travel is adjustable on this fork from about 170mm (for 2006) down to about 130mm, despite the manual and website that say it only goes down to 150mm. This is done with negative pressure, and requires hooking up a shock pump to allow it to be adjusted to less travel.
    ~5.6lbs

    66VF2;
    Right Leg: VF2 orofice damper (like SSVF) w/rebound adjuster on bottom leg, coil spring w/ air preload adjustment.
    Left Leg: ETA cartridge on version that has ETA, on model that does not have ETA called the 66VF2 LT, the left leg has a compression adjuster, coil spring w/ air preload adjustment is also included in both versions.
    A side note, even though this has similer "adjustments" to the other 66 forks, it does not have the same damping system, so on real fast successive hits it will "spike" some and transfer a lot more force to the rider, because the oil can't flow flast enough.
    ~6.2lbs

    Ok, now some general info;

    Notice that both the 66 RC2x, SL, and Light ETA have the exact same cartridge in the right leg.

    ALL forks are adjustable for oil heights on at least the sides that have the dampers, and for the forks that have oil on both sides (like the models with ETA or the RC2x), you can adjust both sides for oil height. This adjusts the progressiveness of the fork and keeps it from bottoming out. Also, the RC2x and 66SL have a specific adjustment for bottom out as well. (the x catridge on the RC2x, and the PAR adjustment on the 66SL).

    RC2 cartridges consist of a low speed compression adjuster up top, and a rebound adjuster on the bottom of the leg.

    The "x" cartridge adjustment from the manual is "compression adjustment at travel end", this means that the "x" cartridge controls bottom-out/progressiveness.

    And on the "air preload"; this is a very low-psi adjustment (usually somewhere between zero and 15 for most riders, despite the manual saying that higher pressures are needed) that makes it so you don't have to buy new springs for different weight riders. You basically get the best of both worlds, coil spring suppleness, and air-adjustability.

    And if you're playing along at home, you'll notice that the 66 Light ETA is actually the HEAVIEST 66 fork, not the 2nd lightest. The term "light" just means that it's missing some features from the top model, which even still isn't quite correct, since instead of missing the "x" cartridge it simply has an ETA cartridge in it's place, although some OEM 66 Light forks do not have ETA. The reason the 66 Light ETA isn't very light is that it takes a lot of oil to make that ETA cartridge work, and oil isn't weightless, so all that oil is what causes it to weigh more than the others.

    Some of these terms carry over to the Z1 series, such as the Z1 Light (eta). The Z1 Light (eta) would have the exact same features and cartridges as the 66 Light (eta). So they are basically similer forks, except the 66 has 20mm more travel, bigger stanchions with a different chassi.
    Last edited by Jayem; 07-15-2006 at 06:13 PM.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  6. #6

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    Thanks alot Jayem!

    Thanks.

    How much would/does the 66 lite ETA adjust the travel. From 170mm to 150mm? If it does, are you still able to bomb DH/FR/AM while using the ETA??

    Thanks again Jayem.

  7. #7
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    Quote Originally Posted by borry
    Thanks.

    How much would/does the 66 lite ETA adjust the travel. From 170mm to 150mm? If it does, are you still able to bomb DH/FR/AM while using the ETA??

    Thanks again Jayem.
    No, ETA is only for climbing or relatively flat stuff. It will reduce the travel in 20mm incriments untill there is only about 30mm of travel left, and about 2" of stanchion showing. Also, if you hit a big enough bump, it will lock the fork down another 20mm depending on the position of the fork. This means that you can really get the front end low to go up steep stuff, which is simply critical IMO, but it's for climbing.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  8. #8

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    Thanks for clearing that up for me. Strictly for climbing, got it!

  9. #9
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    Great thread, and info!

    Im going to hijack this thread, and ask a question....sounds like there are experts. Im just wondering how the compression dampener knows what is high and what is a low speed compression.

    I understand how spv works, pressure keeps the valve closed untill a compression opens up the valve, since ive taken the fork appart many times but this high and low speed compression astounds me.

    Thanks for any help.

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