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2010 Marzocchi 888 A real threat to the lighter forks!

PB Forum :: Downhill
2010 Marzocchi 888 A real threat to the lighter forks!
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flag jinx
Posted: Oct 28, 2009 at 9:35 Quote
Muttley wrote:
Jinx the race really aint all that good, id much prefer a team, and it was the first fork available to me at the time.

I know the 888's are cheap, i considered asking CRC for a refund and getting some RC2X's, but id rather not.

Nothing wrong with the rc3x.
flag stryke
Posted: Oct 28, 2009 at 9:38 Quote
Muttley wrote:
stryke wrote:
you can tune the shim stack in a 40 yes
Really? safe, hows it done? as the cartridge is a bitch to get to. i wanna try some 40's that have had the Bottom outy assy removed, pro style haha.

i dont know as my friend does the tuning for me, but i can ask him if you want~~ the cartridge isnt too hard to service/dismantle as long as you get everything prepared beforehand and have the correct tools/vice shit
flag jinx
Posted: Oct 28, 2009 at 9:50 Quote
stryke wrote:
Muttley wrote:
stryke wrote:
you can tune the shim stack in a 40 yes
Really? safe, hows it done? as the cartridge is a bitch to get to. i wanna try some 40's that have had the Bottom outy assy removed, pro style haha.

i dont know as my friend does the tuning for me, but i can ask him if you want~~ the cartridge isnt too hard to service/dismantle as long as you get everything prepared beforehand and have the correct tools/vice shit

What a mind blowing argument: "my friend..."

I'd expect more from you.
flag Muttley
Posted: Oct 28, 2009 at 9:53 Quote
To be fair it obviously can be done.
flag stryke
Posted: Oct 28, 2009 at 9:53 Quote
i had no idea it was an argument

sorry
flag joexspocent92
Posted: Oct 28, 2009 at 16:45 Quote
sorry about being such a nub, but can someone explain to me what a shimstack is or what happens if its adjusted? i hear about it a lot, but dont really understand the concept
flag TheSpook
Posted: Oct 29, 2009 at 0:32 Quote
signorvince2 wrote:
TheSpook wrote:
marzocchi ... made in italy , china , taiwan , my back yard , the north pole or in hell .. its still gonna suck because its a marzocchi ....

The next time you have a thought, just keep it to yourself.
thats what forums are for ... to voice your opinion
flag Rigaud
Posted: Oct 29, 2009 at 4:18 Quote
TheSpook wrote:
signorvince2 wrote:
TheSpook wrote:
marzocchi ... made in italy , china , taiwan , my back yard , the north pole or in hell .. its still gonna suck because its a marzocchi ....

The next time you have a thought, just keep it to yourself.
thats what forums are for ... to voice your opinion

You didn't voice your opinion since you don't explain the reason behind your comment.

Only reason Marz had problems the last couple of years with the 888 and a few others is they had changed the design internally. Theirs a reason their back with an open bath for 2010 and with the new designed cartridges I saw, looks promissing. I have a 2004 888 that has been bullit proof with 1 oil change per year and original seals. Eek

I have a 2006 Manitou Travis SC 150mm that was so push untill last weekend so I opened it up and unreal how complicated they made it. It's a royal pain in the ass to rebuild especially to reassemble it. Going to gut the internals and put in my own open bath system with cartridges.
flag pbuser102331
Posted: Oct 29, 2009 at 5:11 Quote
joexspocent92 wrote:
sorry about being such a nub, but can someone explain to me what a shimstack is or what happens if its adjusted? i hear about it a lot, but dont really understand the concept

a shimstack is a stack of shims that bend at differing rates allowing more or less oil flow.

basically it controls the flow of oil.
flag joexspocent92
Posted: Oct 29, 2009 at 21:46 Quote
marquis wrote:
joexspocent92 wrote:
sorry about being such a nub, but can someone explain to me what a shimstack is or what happens if its adjusted? i hear about it a lot, but dont really understand the concept

a shimstack is a stack of shims that bend at differing rates allowing more or less oil flow.

basically it controls the flow of oil.

so, what does it do? i looked online at marzocchi's website, but they just say that its highly customizable for the compression. compression always throws me off, because its so complicated. and whats the difference between the RCV and the RC3? does the RCV just have low speed compression while the RC3 has both high and low tied together?
flag pbuser102331
Posted: Oct 30, 2009 at 4:25 Quote
on your suspension shaft you usually have a piston,when the fork hits a bump the piston travels through the oil,now to make resistance you would normally drill holes in the piston to control the flow of oil through these holes,the problem is there not adjustable well they are but they need drilling.

now place shims under the piston and the resistance can be controlled as each shim bends at a differing rate to the last one.

look at compression like your brake,the harder you squeeze the more power you get same with compression in a round about way.

rcv is just rebound,rc3 is automatic as far as i can tell and determines wether the hit was high or low speed.

Unsecure image, only https images allowed: http://www.valvingdatabase.com/hotline/valveInfo/images/shim_03.jpg
[L=http://homepage.eircom.net/~thefoundation/dirtbike/suspension/3twowaypistons.jpg]http://homepage.eircom.net/~thefoundation/dirtbike/suspension/3twowaypistons.jpg[/L]
flag evan547
Posted: Oct 30, 2009 at 6:24 Quote
joexspocent92 wrote:
marquis wrote:
joexspocent92 wrote:
sorry about being such a nub, but can someone explain to me what a shimstack is or what happens if its adjusted? i hear about it a lot, but dont really understand the concept

a shimstack is a stack of shims that bend at differing rates allowing more or less oil flow.

basically it controls the flow of oil.

so, what does it do? i looked online at marzocchi's website, but they just say that its highly customizable for the compression. compression always throws me off, because its so complicated. and whats the difference between the RCV and the RC3? does the RCV just have low speed compression while the RC3 has both high and low tied together?

Oh dear. Where to begin?

Lets start with the RCV. The spring goes boing. As the fork goes through it's travel, the oil is displaced from on side of the damper to the other. In an RCV fork, the resistive force (to the spring) is created by several small oil ports like the SSV of old. Manitous Fluid Flow is like this also. Imagine a PVC pipe with only one end open, but two small holes on the side of the closed end. Were it to be filled with fluid, one could press the fluid out of the two small holes with a plunger. But, if you slammed the plunger really fast into tube and hit the fluid surface, it would feel like you hit a solid. This is what people are talking about when they refer to "spiking" The system works, but has limitations for high speed impacts.

The more sophisticated dampers have stacks of shims to resist the oil flow. As the force of oil increases, the shims will flex more allowing more oil by. This would be like an oil port that magically changes size according to the impact were it an SSV system. Theses shims can be changed to alter to what degree they flex, thereby changing how it lets the oil pass. Furthermore, you can mount this shim stack on a small spring. Initially in this configuration, there will be almost no resistance to oil flow as the oil will compress the spring the stack is mounted on first (assuming the spring is not too stiff). After the spring bottoms out, then the oil blows through the shims. This is a floating shim stack, and gives great small bump sensitivity.

The adjustment dials on the outside of the fork only change things like port size (which there must still be on a shim stack fork). The real deal is on the inside.
flag joexspocent92
Posted: Oct 30, 2009 at 22:47 Quote
evan547 wrote:
joexspocent92 wrote:
marquis wrote:


a shimstack is a stack of shims that bend at differing rates allowing more or less oil flow.

basically it controls the flow of oil.

so, what does it do? i looked online at marzocchi's website, but they just say that its highly customizable for the compression. compression always throws me off, because its so complicated. and whats the difference between the RCV and the RC3? does the RCV just have low speed compression while the RC3 has both high and low tied together?

Oh dear. Where to begin?

Lets start with the RCV. The spring goes boing. As the fork goes through it's travel, the oil is displaced from on side of the damper to the other. In an RCV fork, the resistive force (to the spring) is created by several small oil ports like the SSV of old. Manitous Fluid Flow is like this also. Imagine a PVC pipe with only one end open, but two small holes on the side of the closed end. Were it to be filled with fluid, one could press the fluid out of the two small holes with a plunger. But, if you slammed the plunger really fast into tube and hit the fluid surface, it would feel like you hit a solid. This is what people are talking about when they refer to "spiking" The system works, but has limitations for high speed impacts.

The more sophisticated dampers have stacks of shims to resist the oil flow. As the force of oil increases, the shims will flex more allowing more oil by. This would be like an oil port that magically changes size according to the impact were it an SSV system. Theses shims can be changed to alter to what degree they flex, thereby changing how it lets the oil pass. Furthermore, you can mount this shim stack on a small spring. Initially in this configuration, there will be almost no resistance to oil flow as the oil will compress the spring the stack is mounted on first (assuming the spring is not too stiff). After the spring bottoms out, then the oil blows through the shims. This is a floating shim stack, and gives great small bump sensitivity.

The adjustment dials on the outside of the fork only change things like port size (which there must still be on a shim stack fork). The real deal is on the inside.

so youre telling me that the compression rates can be adjusted even further with the shimstacks? so is compression all about oil going into a small hole at a certain rate? it kinda cleared my mind but i still dont get the difference between RC3 and RCV. if you dont wanna explain its ok haha
flag joexspocent92
Posted: Oct 30, 2009 at 22:50 Quote
marquis wrote:
on your suspension shaft you usually have a piston,when the fork hits a bump the piston travels through the oil,now to make resistance you would normally drill holes in the piston to control the flow of oil through these holes,the problem is there not adjustable well they are but they need drilling.

now place shims under the piston and the resistance can be controlled as each shim bends at a differing rate to the last one.

look at compression like your brake,the harder you squeeze the more power you get same with compression in a round about way.

rcv is just rebound,rc3 is automatic as far as i can tell and determines wether the hit was high or low speed.

Unsecure image, only https images allowed: http://www.valvingdatabase.com/hotline/valveInfo/images/shim_03.jpg
[L=http://homepage.eircom.net/~thefoundation/dirtbike/suspension/3twowaypistons.jpg]http://homepage.eircom.net/~thefoundation/dirtbike/suspension/3twowaypistons.jpg[/L]

thanks! i understand everything what you said, except the last line where you mention RCV and RC3 haha
flag evan547
Posted: Nov 2, 2009 at 11:35 Quote
RCV is just a hole. The hole has to be small enough to restrict oil flow. The force created by this restriction is determined by the orifice dimension, fluid velocity, pressure upstream of the orifice, and the fluid properties among others. The fluid properties and orifice geometry remain constant for an RCV unit. What changes is the driving pressure and therefore fluid velocity. In the end, the damper can't change to cope with the changing conditions.

The RC3 uses oil ports, but they are sufficiently large that they do not obstruct the oil flow. Rather, shims are placed on top of the ports (as posted in the picture earlier) to resist the flow. Now, the orifice dimension is not fixed, but the shims can change the orifice dimensions. This of course makes the calculations much more complex, but the idea is that the flex in the shims allows the damper to react to the changing input(from bumps on the trail).

Check out this link for the science behind the flow.

http://www.engineeringtoolbox.com/orifice-nozzle-venturi-d_590.html

 


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