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  1. #1
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    Marzocchi 55 TST2 set-up help needed

    edit: UPDATE TO ORIGINAL POST BELOW WITH NEW SETTINGS: click here

    edit: UPDATE 2: TST2 damper pics

    edit: UPDATE 3: Possible modification

    edit: UPDATE 4: New settings and results. Cliff Notes version:
    .....Final opinion is that the damper's high speed compression is a bit over the top, not horrible for fast descending - but not great either, but the HSC rocks the freeride stuff!....


    I love the way the 55 TST2 handles big hits and has a pretty controlled behavior.

    But, I'm not diggin' the harsh small bump compliance at speed. Fast boneyards, braking bumps, etc. the fork feels like it is hydraulically locking up similar to a port orofice damper

    I have tried varying air pressures for preload:
    - 10 psi removes harshness, but the fork then behaves like it is undersprung (dive, weak midstroke, etc)

    - 28 psi feels more like the correct spring rate, but I get that hydraulically lock feel in the fast rough stuff

    I've checked oil levels, and am getting ready for the fork's first oil change (about 9 hours ride time). Oil level is currently at 55mm from top.

    I run my rebound pretty fast, but have not yet tested if I could run it faster in the high speed conditions to improve the situation.

    I think it might be the air preload side, as the open bath system might create some of this harsh feel at speed.
    (I am thinking this as the TST 2 damper does not have the harshness when under sprung (10 psi) - the TST2 damper seems to have piston/shim feel to it. Or maybe I am just feeling the air spring deep travel ramp-up on drops. And it really is an orofice damper :-( )

    Would running a lighter oil on the air preload side improve plushness in rough, high speed situations?

    If so what oil should I use?
    Marzocchi oil is Golden Spectro Cartridge Fork Fluid 7.5w (125/150), should I use Golden Spectro Cartridge Fork Fluid 7.5w (85/150)? or another? http://www.spectro-oils.com/products...n/cartfork.asp

    Thanks for any help.

    P
    Last edited by Mr.P; 03-30-2008 at 10:30 PM.

  2. #2
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    Mr P,
    I agree 100% the fork is great for big hits! However, I don’t think the fork will ever be super plush on high speed bumps... at least with either of two cartridges I have ridden. (TST2 & R) We have tried zero and even negative pressure as well as 30 psi… harsh, harsh, harsh! And there will come a time when it get’s even worse… It’s a subtle change not something that seems to happen all at once. (Has happened to be twice)

    First time it blew my TST, all I noticed was the fork would not bottom. Normally I would bottom the fork as least once a ride, then all the sudden I could not reach the last inch or so of travel. I let all the air out and still could not bottom the fork. Sent it to Marzocchi and they installed a new cartridge. (At this point I had been riding the fork about 2 months and had logged about 150 miles) My normal air pressure was around 7 PSI.

    Got the fork back and it was smooth as a baby's butt in the high speed bumps, this was when I realized just how rough the fork was before. back to riding with about 7 PSI and getting 160mm travel. I managed to put another 150 miles or so on the fork, before I once again noticed the fork would not bottom, rode the fork anyway as it was a weekend trip… Fork was harsh in the small stuff, but handled the big hits just fine. Travel was limited to 140-150mm. I can’t really tell you the change took effect on one ride or in one week, it’s more like it happens over several rides and weeks. It’s like all the sudden you realize something just aint right and then you realize the fork travel is limited and the ride is harsh... I let all the air out and tried to force the fork to the bottom, no-go.

    I have a new TST2 cartridge in my possession, going to remove the old and have a look inside… Anyone interested in photos of the inside of the TST2?

    One other thing: one of my riding buddies blew his 55R damper… I helped him install the new one… could not see what’s inside as it is sealed… looks just like the hydraulic cylinder used to hold up a hatchback except both ends are threaded. You can compress the R cartridge but let it go and it will extend... I will say his 55R is just as harsh as the TST2 in small bumps, so you may well be on to something with your statement: “I think it might be the air preload side, as the open bath system might create some of this harsh feel at speed.”

    I have not seen the inside of the 55TST but I will soon… I have photos of the inside of the 55R and I will post both here on your thread… give me a couple of days.

    I don’t know much about forks or shocks but maybe if I post some photos someone will suggest modifications? Life is just a big experiment anyway, so why not modify?

    Good News on the horizon: Marzocchi is going to release a RC2 version of the fork this fall… so maybe we can change the internals of our TST…

    I am not a man of patience… fall is to far away… I am now riding a 66 RC3! 55 is in the closet

  3. #3
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    Quote Originally Posted by flyag1
    Mr P,
    I agree 100% the fork is great for big hits! However, I don’t think the fork will ever be super plush on high speed bumps... at least with either of two cartridges I have ridden. (TST2 & R)
    Thanks for the feedback! I was just reading your posts today, and was playing with lower pressures as a result.

    I responded to one of your posts a few months back where you described the small bump feel, and I bought the fork anyway...

    And you are not the only one that has had a bad damper....

    grumble.... grumble....

    But I like the fork for all but the high speed spiking...

    P

  4. #4
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    Quote Originally Posted by flyag1
    I have a new TST2 cartridge in my possession, going to remove the old and have a look inside… Anyone interested in photos of the inside of the TST2?
    I would love to see those insides. It would tell me if what is wrong is my set up (piston/shim damper) or it's the damper (orifice damper).

    P

  5. #5
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    Quote Originally Posted by Mr.P
    I would love to see those insides. It would tell me if what is wrong is my set up (piston/shim damper) or it's the damper (orifice damper).

    P
    I wondered if you noticed that statement? I will be changing my cartridge soon and will post images here for all to enjoy....

    Are you getting full travel on your fork?

  6. #6
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    Quote Originally Posted by flyag1
    I wondered if you noticed that statement? I will be changing my cartridge soon and will post images here for all to enjoy....

    Are you getting full travel on your fork?
    Me likey pictures thanks!

    I just checked the travel and I get full travel.

    Gotta ask how the 66 RC3 is?

    P
    Last edited by Mr.P; 03-17-2008 at 11:48 PM.

  7. #7
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    I haven't worked on the newer tst systems, but have on the old tst that came on 05 and 06 all mountain 1's. My brother has one of each, and I have changed the oil in the open bath and cartridge for him. I replaced the open bath with 5 wt silkolin (I'm not sure what the correct spelling is, and i'm to lazy to look it up), from the stock 7.5 golden spectro, and replaced the cartridge oil with 2.5 golden spectro. The forks became much more lively, and less harsh. Before the only setting on the 5 tst that was operable was full open. After the second setting also worked when less brake dive was needed.
    So if it's possible try swapping out the cartridge oil for a lighter oil.
    Bunk
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  8. #8
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    Quote Originally Posted by farmboybunk
    I haven't worked on the newer tst systems, but have on the old tst that came on 05 and 06 all mountain 1's. My brother has one of each, and I have changed the oil in the open bath and cartridge for him. I replaced the open bath with 5 wt silkolin ...
    Bunk

    Thanks! That is helpful. I think the TST damper is a closed unit for Marz only service. I hope not, as I would like that adjustability and frequency of service for myself.

    Like your experience, I am only getting noticeable full open or lock-out, can't really feel a difference with the settings in between.

    It'll be interesting to see the cartridge innards when flyag1 posts with the pics.

    P

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    Update To Original Post

    UPDATE

    I was able to ride the same trails and stunts as my original post but with different settings, based on feedback and my own feel.

    The spring side oil weight has no relationship to damping as far as I can tell so I was way off base on that one.

    I lowered air pressure to ~22psi, oil level at 55mm and sped up rebound. Pre-ride I turned the bike (fork) upside-down for 30 seconds and cycled the fork an inch or two a couple times. This gets a fresh coating of oil to the upper seals and stanchions eliminating stiction thereby greatly increasing small bump compliance, especially at low speed.

    I am happy to report that small bump compliance has improved while maintaining big hit capabilities. Stiffening through the boneyards is greatly reduced, tho a bit still remains (but it feels similar to a 36 Van I've ridden, and a TPC+ Nixon). The stiffening now feels more "fluid" than the "spiking" of my previous report - firm but not harsh.

    I think I had the fork over-sprung and perhaps a bit over-damped in the rebound circuit.

    For me (180#, 06 Enduro, ride fast straight through boneyards, jumps, etc.) the recommended air pressure (0-15 psi) is too low. It felt to undersprung and gave no pop for jumps or bunny hops - while my rear had pop = Mismatch! Yikes!

    So great improvement with better settings. I still have more tuning which should improve things a bit. Next up is to lower the oil level to get closer to full travel, and should reduce some of the spring rate ramp-up in mid-stroke that affects the fast bump compliance. Bottom line is that this was ride #4 and things should improve from here as I keep noodling and the fork breaks in more.

    P

  10. #10
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    Cartridge from 2008 Marzocchi TST2

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    2008 Marzocchi 55R




  12. #12
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    Quote Originally Posted by flyag1
    Cartridge from 2008 Marzocchi TST2
    Hmmm. That is interesting. Looks kinda like a TPC set-up - set top piston separated from the rebound and oil gets pushed up.

    Can't tell if it is a orofice or piston/shim damped.

    P

  13. #13
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    Quote Originally Posted by flyag1
    2008 Marzocchi 55R



    I am surprised by the "R" cartridge. I expected it to just be neutered TST2, but it looks very different.

    Thanks so much for the pics flyag1 !



    P

  14. #14
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    TST2 Cartridge insides!

    flyag1 sent me these pics of the inside of the TST2 damper and did my best to point out the different functions.

    We both have questions as to how the damper locks out as the lock-out orifice is on a separate top piston assembly rod than the compression piston and shim which is on the bottom assembly.

    The good news: TST2 has piston/shim damping for both compression and rebound.

    The bad news: how can such a simple looking system have the number of failures that are showing up?

    I'll let the pics speak for themselves.

    Thanks to flyag1 for taking the damper apart and for taking the time to take such great pics

    P

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    Last edited by Mr.P; 03-27-2008 at 11:26 AM.

  15. #15
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    Quote Originally Posted by Mr.P
    flyag1 sent me these pics of the inside of the TST2 damper and did my best to point out the different functions.

    We both have questions as to how the damper locks out as the lock-out orifice is on a separate top piston assembly rod than the compression piston and shim which is on the bottom assembly.

    The good news: TST2 has piston/shim damping for both compression and rebound.

    The bad news: how can such a simple looking system have the number of failures that are showing up?

    I'll let the pics speak for themselves.

    Thanks to flyag1 for taking the damper apart and for taking the time to take such great pics

    P

    Bro, that's great info...

    However, I think you have it a bit mixed up. The piston on with the lockout is indeed the compression. All open with just a stiff blow-off when you close it. Very ETA-like.

    The rebound is the lower piston... What you see with the spring washers are just check valves (one way valves) that allow free flow in one direction and restrict the flow in the opposite.

    How this simple system can fail by limiting travel little by little?? I have no clue... Other than oil migrating from the semi-bath to the cartridge. Because high oil from the get go, will just limit travel from the first time you use the fork.

    Maybe air build up in the cart as in MX forks???

    Also, I don't see special tools needed to service it and looks dead easy to work on, but you can confirm if that's true or not.
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    Thanks Warp,

    The cartridge was very easy to open... just unscrew the both ends off a threaded tube... and your done... I do understand the (top) thing-a-ma-gig is the compression side and lock out... whereas the bottom is the rebound... and the check valve in the rebound side makes perfectly good sense as does the restrictor needle.

    However the top thing-a-ma-gig (lock out and compression) is not computing.... maybe I don't understand the fluid levels? should the cartridge be completely full of oil?

    If the answer is yes: then closing the the TST valve... (turning the lock out to the closed position) you basically block the top 50% of the cartridge... as if the cartridge is now only 1/2 it's original length... and the bottom 50% should still function normally.

    If the top 1/2 of the cartridge is air filled then we have a different animal. It this is the case, then on really big hits fluid could be pushed into the air chamber which could result in a negative pressure below the rebound piston. Basically the top portion of the cartridge becomes a blow off reservoir and without the extra volume the orifices in the rebound piston (check valve and needle) will dramatically restrict fluid movement.

    In second scenario: where there is air in the top 1/2 of the cartridge... and a negative pressure below the piston is possible... then failure of the cartridge performance can be induced by the vacuuming of oil into the cartridge from the oil in the lower portion of the fork. Basically, the seals in the lower porting of the cartridge allow the lubricating oil in the lowers to be sucked up into the cart... resulting in cartridge overfilling and loss of travel.

    How is that for root cause analysis? To prove the point, just put red oil in fork lowers and clear in cartridge, when cartridge fails then open cartridge and most likely you will find red die in cartridge oil. Tell Marzocchi to install two way seal in lower cartridge and issue fixed!

    Now we can start to work on a fix for small bump compliance?

  17. #17
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    Quote Originally Posted by Warp
    Bro, that's great info...

    However, I think you have it a bit mixed up. The piston on with the lockout is indeed the compression. All open with just a stiff blow-off when you close it. Very ETA-like.

    The rebound is the lower piston... What you see with the spring washers are just check valves (one way valves) that allow free flow in one direction and restrict the flow in the opposite.

    How this simple system can fail by limiting travel little by little?? I have no clue... Other than oil migrating from the semi-bath to the cartridge. Because high oil from the get go, will just limit travel from the first time you use the fork.

    Maybe air build up in the cart as in MX forks???

    Also, I don't see special tools needed to service it and looks dead easy to work on, but you can confirm if that's true or not.
    I think you are right, that those piston/shims are check valves. Doh! That means the damping is orifice based. Boooo! That means only an oil weight change will affect the high speed spikes. Booo! 2008 and still orifice dampers.

    Unless.... Those gigantic blow off shims get replaced with a proper shim stack.... Possible? The orifice already flows so much oil... And why make the blow-off so heavy duty any way. Marzo told me on the phone that mid-setting lock out was a bad idea during non-climbing, even tho there is a blow-off, it could crap the damper...

    P

  18. #18
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    Quote Originally Posted by flyag1
    Thanks Warp,

    The cartridge was very easy to open... just unscrew the both ends off a threaded tube... and your done... I do understand the (top) thing-a-ma-gig is the compression side and lock out... whereas the bottom is the rebound... and the check valve in the rebound side makes perfectly good sense as does the restrictor needle.

    However the top thing-a-ma-gig (lock out and compression) is not computing.... maybe I don't understand the fluid levels? should the cartridge be completely full of oil?

    If the answer is yes: then closing the the TST valve... (turning the lock out to the closed position) you basically block the top 50% of the cartridge... as if the cartridge is now only 1/2 it's original length... and the bottom 50% should still function normally.

    If the top 1/2 of the cartridge is air filled then we have a different animal. It this is the case, then on really big hits fluid could be pushed into the air chamber which could result in a negative pressure below the rebound piston. Basically the top portion of the cartridge becomes a blow off reservoir and without the extra volume the orifices in the rebound piston (check valve and needle) will dramatically restrict fluid movement.

    In second scenario: where there is air in the top 1/2 of the cartridge... and a negative pressure below the piston is possible... then failure of the cartridge performance can be induced by the vacuuming of oil into the cartridge from the oil in the lower portion of the fork. Basically, the seals in the lower porting of the cartridge allow the lubricating oil in the lowers to be sucked up into the cart... resulting in cartridge overfilling and loss of travel.

    How is that for root cause analysis? To prove the point, just put red oil in fork lowers and clear in cartridge, when cartridge fails then open cartridge and most likely you will find red die in cartridge oil. Tell Marzocchi to install two way seal in lower cartridge and issue fixed!

    Now we can start to work on a fix for small bump compliance?
    The way I understand it, it works like a rear shock but with no separating (at least not floating) piston between the air and oil.

    Oil (and I have no experience at all with the TST2, so take it with a grain of salt) should be just covering the compression piston. As the plunger shaft that holds the rebound piston enters the cart, it will displace oil and occupy space into the air chamber.

    If you lock it, you just prevent oil from displacing and it will flow only if you go over the blow off threshold. Oil can flow back down thanks to the check valve.

    If you have the oil lower than the piston, then you can have the problems you're mentioning.

    For small bump compliance, try a pressure (the cartridge is pressurized, right??) lower than indicated and/or a lighter oil than stock.
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  19. #19
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    Quote Originally Posted by flyag1
    In second scenario: where there is air in the top 1/2 of the cartridge... and a negative pressure below the piston is possible... then failure of the cartridge performance can be induced by the vacuuming of oil into the cartridge from the oil in the lower portion of the fork. Basically, the seals in the lower porting of the cartridge allow the lubricating oil in the lowers to be sucked up into the cart... resulting in cartridge overfilling and loss of travel.

    How is that for root cause analysis? To prove the point, just put red oil in fork lowers and clear in cartridge, when cartridge fails then open cartridge and most likely you will find red die in cartridge oil. Tell Marzocchi to install two way seal in lower cartridge and issue fixed!

    Now we can start to work on a fix for small bump compliance?
    Brilliant! Too much oil make sense. I just found this on Dougal's Manitou FAQs page:
    TPC manitous also need a large air space in the damper. This is because they work on displacement (volume change) and the oil level rises in the stanchion as the fork compresses.
    Too much oil causes hydraulic lock, too little causes cavitation and both can damage your fork.
    Great to know the damper is an easy break down.

    It seems the air springs in the ATAs are having issues. I wonder if the seals Marzo (Suntour) is getting are poor spec. Like the Fox "stuck down" epidemic of a few years ago (at least that was the official line).

    I dunno on the small bump compliance, I can only guess it is the air preload seals.

    P

  20. #20
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    Quote Originally Posted by Mr.P
    I think you are right, that those piston/shims are check valves. Doh! That means the damping is orifice based. Boooo! That means only an oil weight change will affect the high speed spikes. Booo! 2008 and still orifice dampers.

    Unless.... Those gigantic blow off shims get replaced with a proper shim stack.... Possible? The orifice already flows so much oil... And why make the blow-off so heavy duty any way. Marzo told me on the phone that mid-setting lock out was a bad idea during non-climbing, even tho there is a blow-off, it could crap the damper...

    P
    You're on the right track, P.

    Indeed, you would improve the damper by adding shims and closing a bit the main orifice.

    I don't know why the stiff blow off... The TST5 is equally stiff.
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    More pics!

    flyag1 sent over some more pics for posting.

    They can speak for themselves.

    Tuning options on the damper seem to include:
    - lighter weight oil (the ham fisted approach - but effective)
    - modify the blow off with a thinner and perhaps pyramid shim stack ( I guess one would have to start with a good amount of shims based on what is stock)

    Anyone else with any more ideas?

    P
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    Potential Improvement to Damper

    So I got thinking about the blow off to shim stack, and began to think it is quite feasible.

    After all it would only be used when the oil pressure starts to spike.

    By putting lighter shims in a pyramid stack, lockout would be more like a platform, and high speed compressions would be directed through the shim stack reducing spikes. Does this sound accurate?

    Anyone have any thoughts on implementation? It's so easy to think about but reality is a bit different

    Pics of potential change below.

    flyag1 measured out the stock blow off shims:
    "There are actually 4 shims in the factory stack, (0.32 ID X 0.790 OD x 0.016 thick)"

    One other possibility would be to reduce to blow off shim stack to just one shim. It would not be a progressive stack but working in conjunction with the orifice damper, might reduce the high speed spikes. Thoughts anyone?

    Flyag1, was there any nitrogen in the cartridge? And if it is a seal issue that makes the cartridges crap out, any way for us to fix on a more permanent level?

    P
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    UPDATE: New settings, damper info and ride report

    Another ride Another tweak.

    The Cheese gave me a good tip to lower my oil height (while at same psi) to reduce down the spring rate mid-stroke. It was on the to-do list as my 55mm (Marz rec) height was not giving me full travel (about 30mm short), but his input made me be a bit more aggressive.

    Settings:
    23psi, oil height 62mm, rebound fast as reasonable

    So I took the spring out and reduced the oil level to 62mm from crown.

    While the spring was out, I decided to run some tests on the damper:

    - no spring (coil & air), damper open = damper gets progressive at 60mm to bottom. Progressive to the point where it requires my full body weight to reach bottom. Air or nitrogen compression in damper? Me thinks less need for spring progressiveness. EDIT: it is the air in the damper side leg that was creating the progressiveness.

    - no spring (coil & air),damper closed to lock out = super damped but still travels, rebound is damped normally.

    Ride results:
    - Same trail as all above.
    - 150mm travel with a nose heavy landing on a 4' drop. I'll save that last 10mm for a nasty oops incident.
    - Small stuff at a moderate speed was invisible (I think my turning the fork upside down to lube the bushings helped the small bumps)
    - 2-3" rocks at high speed were firm, but did not feel spiked like an RV type damper
    - I nose heavied a 4' drop, over shot the landing on a 6' gapper, poorly landed a near flat landing and the fork just sucked it up without complaint. I love this fork for that.

    So, final opinion is that the damper's high speed compression is a bit over the top, not horrible for fast descending - but not great either, but the HSC rocks the freeride stuff!

    I need to try this fork at Downieville - which can get very fast and rough - to see if it is a keeper.

    Also, if the damper craps out on me, I might just try adjusting the blow off to a firm shim stack.

    I want to keep the lock out as it can make a fast & efficient ascender on short out of saddle steeps. Never thought I would say that about a 160mm fork.

    P
    Last edited by Mr.P; 03-31-2008 at 11:07 AM.

  24. #24
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    Quote Originally Posted by Mr.P
    Another ride Another tweak.

    spring (coil & air), damper open = damper gets progressive at 60mm to bottom. Progressive to the point where it requires my full body weight to reach bottom. Air or nitrogen compression in damper? Me thinks less need for spring progressiveness.

    high speed compression is a bit over the top, not horrible for fast descending - but not great either, but the HSC rocks the freeride stuff!

    P
    Mr P,
    TST cartridge has no charge (no air... no nitrogen)

    Yes the fork does get progressive... even with the spring side open,but it's not the TST cartridge. It's the fork leg itself, as it is sealed. Larger oil volumes in the fork legs will also allow greater buildup pressures inside the fork. Need a stiffer fork, add oil...need more travel and a softer ride take away oil....

    It's even possible to have negative pressure in the right side of the 55 TST. To set up negative, remove cap and spring from left side... unscrew cap from TST side and compress fork and press the top cap of the TST cartitdge back into the right leg and re-tighten the top cap. Try to extend the fork and you will find if very difficult as the negative pressure will not allow you to do so....
    Negative pressure could be used to decrease Crown to axle length?
    Negative pressure could be used as a top out bumper?
    Maybe the negative would provide small but plushness?
    Of course, negative pressure would decrease usable travel.

    I totally agree the shims are causing issues with high speed plushness. As you suggested I am experimenting with a lighter pyramid shape compression stack of shims, backed by a heaver stack. In theory small hits only require small volumes of oil movement, where as big hit will require larger volumes. The lighter shims at the beginning of the stack should allow small volumes of oil to pass the compression piston with very little resistance. The heaver shims behind the lighter stack should restricting total volume and induce pressure buildup inside the TST cartridge for big hits Hence: progressive travel... The air pressure buildup inside the sealed legs will aid in the progressive travel as well....

  25. #25
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    Quote Originally Posted by flyag1
    Mr P,
    TST cartridge has no charge (no air... no nitrogen)
    Great info, thanks. So it is filled to the brim with oil. Doesn't the oil need a space to fill on compression?

    Quote Originally Posted by flyag1
    Yes the fork does get progressive... even with the spring side open,but it's not the TST cartridge. It's the fork leg itself, as it is sealed.
    Doh! I forgot about the cartridge side!

    Quote Originally Posted by flyag1
    It's even possible to have negative pressure in the right side of the 55 TST. To set up negative, remove cap and spring from left side... unscrew cap from TST side and compress fork and press the top cap of the TST cartitdge back into the right leg and re-tighten the top cap. Try to extend the fork and you will find if very difficult as the negative pressure will not allow you to do so....
    Negative pressure could be used to decrease Crown to axle length?
    Negative pressure could be used as a top out bumper?
    Maybe the negative would provide small but plushness?
    Of course, negative pressure would decrease usable travel.
    Very clever! I did something similar to my wifes fork, only created negative pressures on both sides to reduce coil spring rate. It worked great for her.

    I wonder if this could work for small bump stuff? I bet it would. It might pull down the sag a bit, but the key would be to find that perfect balance between left and right leg pressures.

    Or maybe just get a custom made coil for the coil side, no longer use the Air Preload, and let the static pressures add the progressiveness.

    There is already a coil negative spring on the coil side.

    P
    Last edited by Mr.P; 03-31-2008 at 10:38 AM.

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    Nice work guys. It great to see how the new dampers are.

    It is interesting to see how Marzocchi tried to overcome the problems of the TST5 cartridge. And what I mean here was the blowing of the blander. The old TST5 cartridge used the rubber blander for the amount of oil that was dislocated by the rebound rod during compression. If some oil leaked from the cartridge, then air would get in during the rebound phase. And air into the cartridge meant that the compression piston didn't work anymore (it needs to be completely in oil).

    With the new design the rubber blander is replace by the air chamber above the compression piston. The piston needs to be immerse into oil but, there needs to be a decent amount of air above it. So there is a specific amount of oil that needs to be put in the cartridge. At least this is what one can see from the pictures.

    Those my believe is that blown cartridges are due wrong amount of oil. The cartrige will be damaged if there is too much oil in the damper! Just think about it. Under compression the oil dislocate by the rebound rod will not have where to go (even if there is a bit of air in the cartridge the pressure will extremely rump up). And the only way out of the damper is the rebound rod seal or one of the seal s of the upper or lower caps. If one of these seals brake, than the oil will be out and there will be no compression.

    Thus I think that someone (Marzocchi!!!) needs to come up with the right oil levels for new TST cartridges. If I would have such a fork I would take out the cartridge and try to put as few oil into the damper as possible before using it. As usual Marzocchi has good design but screw things up at the assembly.

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    Quote Originally Posted by macadam
    Nice work guys. It great to see how the new dampers are.

    It is interesting to see how Marzocchi tried to overcome the problems of the TST5 cartridge. And what I mean here was the blowing of the blander. The old TST5 cartridge used the rubber blander for the amount of oil that was dislocated by the rebound rod during compression. If some oil leaked from the cartridge, then air would get in during the rebound phase. And air into the cartridge meant that the compression piston didn't work anymore (it needs to be completely in oil).

    With the new design the rubber blander is replace by the air chamber above the compression piston. The piston needs to be immerse into oil but, there needs to be a decent amount of air above it. So there is a specific amount of oil that needs to be put in the cartridge. At least this is what one can see from the pictures.

    Those my believe is that blown cartridges are due wrong amount of oil. The cartrige will be damaged if there is too much oil in the damper! Just think about it. Under compression the oil dislocate by the rebound rod will not have where to go (even if there is a bit of air in the cartridge the pressure will extremely rump up). And the only way out of the damper is the rebound rod seal or one of the seal s of the upper or lower caps. If one of these seals brake, than the oil will be out and there will be no compression.

    Thus I think that someone (Marzocchi!!!) needs to come up with the right oil levels for new TST cartridges. If I would have such a fork I would take out the cartridge and try to put as few oil into the damper as possible before using it. As usual Marzocchi has good design but screw things up at the assembly.



    One thing... I may be dead wrong, but I seem to recall the TST2 had to be pressurized (at least for 2007's???) as people on a Spanish board was fixing the travel issues with the TST2's by letting air scape, letting some oil to come off and pressurizing again to 40psi or so (recommended by Marzocchi was in the order of 140psi or so).
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    Can one add air into the cartridge? Is there a valve on the top cap? Can't really see one in the pictorials. Can some post a picture of the top cap?

    It can also be that this year TST2 is different from the 2007 model. Any idea?

    I doubt there a valve with which one can set the pressure in the cartridge. Unless the blow-off shims don't need to be pressurized I don't see why needs to have air pressure into the cartridge.

    I really wonder how someone can "bend" that blow-off shims under compression and let the oil pass!

    Adrian

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    Quote Originally Posted by macadam
    Can one add air into the cartridge? Is there a valve on the top cap? Can't really see one in the pictorials. Can some post a picture of the top cap?

    It can also be that this year TST2 is different from the 2007 model. Any idea?

    I doubt there a valve with which one can set the pressure in the cartridge. Unless the blow-off shims don't need to be pressurized I don't see why needs to have air pressure into the cartridge.

    I really wonder how someone can "bend" that blow-off shims under compression and let the oil pass!

    Adrian
    I think the 2007's were slightly different... But let's hope someone with first hand experience chime in.

    I don't see a reason to have the cartridge pressurized, either... When I get home I'll get the source where I got the info about the pressure on the 2007's.

    I also don't understand Marzocchi's reasoning behind the stiff blowoffs. The one on the TST5 is a heavy, thick shim preloaded with a stiff spring.

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    Before anyone comments: my photochop skills are lacking but here is my understanding of the min oil level. You can also see the relative size of the air chamber above the rebound piston... per Marzocchi no pressure required . I was told to install the compression side of the cartridge, flip the cartridge pside down and fill the rebound side with 2.5 wt oil. Then insert the rebound piston / rod and torque. Following there instructions you will end up with the oil level as depicted in the cutaway... .


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    Quote Originally Posted by flyag1
    Before anyone comments: my photochop skills are lacking but here is my understanding of the min oil level. You can also see the relative size of the air chamber above the rebound piston... per Marzocchi no pressure required . I was told to install the compression side of the cartridge, flip the cartridge pside down and fill the rebound side with 2.5 wt oil. Then insert the rebound piston / rod and torque. Following there instructions you will end up with the oil level as depicted in the cutaway...
    Ha! You are rockin' Photoshop!

    Did they ask you put the TST in "locked" position?

    Is the 2.5w oil different than what they specced? Or is the same?

    P

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    No air ports on the 2008 TST2


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    Quote Originally Posted by Mr.P
    Ha! You are rockin' Photoshop!

    Did they ask you put the TST in "locked" position?

    Is the 2.5w oil different than what they specced? Or is the same?

    P
    Oil is spec... and they did not specify tst in locked position... hence: in our personal communication I wrote, " I think before we post the oil levels, I better verify everything works correctly"

    Almost everything in life is experimental

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    Hi flyag1,

    this sounds pretty good. However, I would say that one would need a bit of oil over the compression piston, like 1 or 2mm above. If you follow the procedure you just describe, it might happen that the compression piston will not be into oil. And in this case the lockout, and the compression adjust will not work (similar to Rock Shox MC, Manitou TPC).

    I would rather mount the rebound first, then poor oil into the cartridge. Cycle the rebound rod couple of times (with the rebound fully open) to let the oil get beneath the rebound piston. You should have the rebound piston all the time covered by oil. Then I would measure the length of the compression unit, from the compression piston to the o-ring that seals the cartridge, lets say it has length X. Then, with the rebound rod fully extended (all way out the cartridge) set the oil level to X plus 1-2mm. In this way you are sure you have the piston sinked in oil. Then insert the compression unit, with the compression fully open. Basically is the same procedure like on the Manitou TPC/SPV forks.

    Adrian

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    Quote Originally Posted by flyag1
    Before anyone comments: my photochop skills are lacking but here is my understanding of the min oil level. You can also see the relative size of the air chamber above the rebound piston... per Marzocchi no pressure required . I was told to install the compression side of the cartridge, flip the cartridge pside down and fill the rebound side with 2.5 wt oil. Then insert the rebound piston / rod and torque. Following there instructions you will end up with the oil level as depicted in the cutaway... .
    I think you have the procedure right, the illustration wrong.

    As per the illustration, if you extend the rebound rod, you'll end up with the compression piston depleted of oil. So oil level should be very close to the very top of the cartridge when the cart is completely compressed.

    The procedure that was given to you is correct. You can do the other way around and measure the total depth of the compression assembly from the top threads to the upper face of the compression piston, then install the rebound rod, add oil up to the compression piston upper face depth and close the cart.

    It's pretty much like a rear shock... Just that there is not IFP. In a shock, shock compression will move the IFP making the chamber smaller, on the TST2 (and Micro??) the compression assembly is stationary and the cartridge compression will raise the oil level past the compression piston.... just like Macadam mentioned.

    Adam... I think air in the cart is not an issue... They just have to make sure oil covers the compression piston at rebound's full extensionas you well mention.
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    Thanks for the pictures. Now we have almost the complete description of the TST2.

    One more thing. How is the compression adjusted? is the same type of internal rod, like on the rebound?

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    Quote Originally Posted by macadam
    One more thing. How is the compression adjusted? is the same type of internal rod, like on the rebound?
    Looks like it works like the ETA to me... An inner shaft inside the main shaft just closing/opening an orifice.

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    Hi all - quick question I hope one of you can answer. My 55 TST2 has too much oil in (can't get the last 20mm of travel) and I've been told (by Marzocchi Tech Support on here) to let some oil out. Does this just involve loosening the nut at the bottom of the non-TST side?

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    Hi arctic,

    if you want to remove some oil from the TST2 I would open the top cap, the compression unit and remove from there. I would remove the compression unit completely and then measure the oil level such that it matches the length of the compression unit.

    Adrian

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    Thanks macadam. Do you mean the large nut where the TST control is?

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    yes, the big top cap. Take a good look at this thread, and pay attention to the pics. Go through all the posts before working on the cartridge, there is great info which might come handy during the service.

    Adrian

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    Thanks

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    Quote Originally Posted by arctic303
    Hi all - quick question I hope one of you can answer. My 55 TST2 has too much oil in (can't get the last 20mm of travel) and I've been told (by Marzocchi Tech Support on here) to let some oil out. Does this just involve loosening the nut at the bottom of the non-TST side?

    You need to remove the TST2 cartridge from the fork. Make sure the lock-out is in the open position. Then loosen the nut on the bottom of the cartridge and compress it completely. You can also loosen the top cap. Do this with either open side up. When you compress it and comes out it is over filled. You can then reextend it and retighten the endcap and reinstall it in the fork with 30cc's of oil in the stanchion for lubrication. Make sure everything is tight. Game on.
    Last edited by Marzocchi Tech Department; 04-09-2008 at 08:26 PM.
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    I have played with different fluid levels and here are couple of things to really watch for:

    First you must not over fill or you can't get full travel, that is where you are now...
    Second, to little oil and you will not have any compression dampening...

    Look back at the cutaway I posted a few days ago, you will see the minimum oil level. If you put just the minimum amount of oil in the cartridge with the rebound rod extended (all the way out) then when you push the rod into the cartridge you will displace a larger amount of oil then one would expect: the rod itself will displaces 30mm or fluid... this is not a misprint! 30mm or oil...

    So you want minimum oil levels to start with other wise it's becomes an airspring with compressed.

    Start with removing the top cap of the cartridge... there is no need to remove the bottom. The reason for removing the top is that the top (compression) piston is fixed and you can't cycle the piston which you will need to do... cycling the piston on the bottom will insure you don't have air trapped underneath...

    With the top cap and compression piston removed fill the cartridge nearly full and cycle the lower piston up and down to insure there is no air trapped below the piston. Now set the oil level @ 110 mm below the top rim of the cartridge. This will allow you 2mm of oil above the compression piston once the top cap is re-installed. Reinstall the top cap... done.

    Once you have the top cap tight you should be able to cycle the rod in and out with ease, there may be just a little resistance when the rod is fully inserted... just enough that the rod may try to extend on it own, an 1inch or so...

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    You guys are rocket scientist!!

    Wow, You guys have it all going. I read the post and three of you are talking about two different versions and now ETA pics.. wow their partners.

    Here's the deal. TST5 with external bladder, TST5 micro has an internal bladder, TST2 has no bladder and YES, it works just like TPC (Not my doing).


    TST2 is designed to be a climbing feature with limited performance. Which means all positions other than full on and full off will have their limitations. Orifice damping is speed sensitive there is no way around it. It does what it was designed to do, lock-out and un-lock.

    The current version of the TST2 had a stack of washers on the compression ports to block compression flow when the top adjuster is turned to it's firmest setting. It does not blow off and will spike like a mad dog. This is an orifice damper. The compression ports on the piston never do anything. The washers that are on there will be the last part to move.

    Here's what can be done. I did it and like it too but you loose the lock-out and turn it into a ripping performance setting. You will need 3 shims @ 18mm x 0.15mm thick with an 8mm ID hole. You will also need 3 washers 11mm OD by 11 ID. They need to be about 1mm thick.... Warning, if you break it you will pay for a new one.

    So take the top compression assembly and unscrew the piston. It has thread lock on the bolt so a little heat will help remove it.

    Now, on what would be the top of the piston group (that you hopefully didn't drop and parts are everywhere), remove the 4 thick washers closet to the thread of the bolt.

    You can now install the 3x18x0.15 shims and 3x11x 1mm washers. Apply thread lock and reinstall the piston group on the shaft.

    Done. Now just refill the TST cartridge, introduce the compression assembly as much as possible, compress, and tighten the cartridge. Install it and check it out. You will loose a lot of the lock-out feeling but oh my god, on the trail you will have a nice range of compression. It will be subtle and welll controlled.

    The bladder style cartridges (TST5 and TST micro), I would not recommend doing any modifications unless you have a machine shop to help you out. Those systems are a lot more involved to create a compression feature, that's where RC2 comes in.

    Have fun, be careful.

    ....and I call this a day off....
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    Sorry guys.. loosened the top cap but can't turn any further as the TST lever hits the side. Either this lever just pulls off somehow or I need to loosen the nut at the bottom?

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    Quote Originally Posted by arctic303
    Sorry guys.. loosened the top cap but can't turn any further as the TST lever hits the side. Either this lever just pulls off somehow or I need to loosen the nut at the bottom?
    Just pull straight up it held on with o-rings.

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    Getting there. Undone the top cap, now I can pull it up about 10mm but not any further. Do I need to undo the bottom now?

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    Well.. all looks pretty simple inside except I obviously don't have the right tools for the job. Removed the cartridge but couldn't get the nut undone at all. Re-assembled it and now it's as it was (minus 20mm of travel) and the TST doesn't work at all. What a mare..

    [edit] - fiddled about a bit with the cartridge extending it and then compressing and the TST is working again. I did notice that even without the cartidge installed, I could only compress the fork to 140mm travel so it's obviously not the TST anyway. Maybe this is normal, perhaps the spring is just too stiff? Tried putting my whole weight on the front wheel but can't get that last 20mm. Still, it's better than it was half hour ago.
    Last edited by arctic303; 04-03-2008 at 05:57 PM.

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    Quote Originally Posted by arctic303
    Well.. all looks pretty simple inside except I obviously don't have the right tools for the job. Removed the cartridge but couldn't get the nut undone at all. Re-assembled it and now it's as it was (minus 20mm of travel) and the TST doesn't work at all. What a mare..

    [edit] - fiddled about a bit with the cartridge extending it and then compressing and the TST is working again. I did notice that even without the cartidge installed, I could only compress the fork to 140mm travel so it's obviously not the TST anyway. Maybe this is normal, perhaps the spring is just too stiff? Tried putting my whole weight on the front wheel but can't get that last 20mm. Still, it's better than it was half hour ago.
    I am interested to know if you could push the rod all the way into the cartridge when you had it out? If you could then everything is ok... no need to drop oil!

    Also, did you let all the air out of the left side before you tried to compress? It is not easy to compress... need to ride into a curb to hit bottom:^)

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