Fork internals
#1
Part of the furniture
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Fork internals
Hi all
Went to the Lbs today to fork out some forks .
Anyway. They had the MXproETA there and i liked it A LOT. They didnt have the Z1 series but they had a DirtjumperII which is exactly the same as the Z1 in terms of appearance/crown/stanchions/sliders. I have to confess that the new Z1/DJ crown is veeeeery different to the pics i have seen so far...very beefy ...and i am a bit undecided on if i like it or hate it. Anyway....my first look shocked me a bit and i lean towards the Mxpro stuff. I would like to know in detail if anyone knows about the internals of the MXproETA. I have downloaded manual from marzocchi site but no details there. I cannot understand the coil/air concept at all. Anyone can explain me in nice mechanical/engineering terms how does this work and maybe a brief description of it's schematic. Thanks All
Went to the Lbs today to fork out some forks .
Anyway. They had the MXproETA there and i liked it A LOT. They didnt have the Z1 series but they had a DirtjumperII which is exactly the same as the Z1 in terms of appearance/crown/stanchions/sliders. I have to confess that the new Z1/DJ crown is veeeeery different to the pics i have seen so far...very beefy ...and i am a bit undecided on if i like it or hate it. Anyway....my first look shocked me a bit and i lean towards the Mxpro stuff. I would like to know in detail if anyone knows about the internals of the MXproETA. I have downloaded manual from marzocchi site but no details there. I cannot understand the coil/air concept at all. Anyone can explain me in nice mechanical/engineering terms how does this work and maybe a brief description of it's schematic. Thanks All
#2
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#3
Part of the furniture
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Thank dirtbikedude...but i come straight from there....having disassembled totally my manitou fork i became a bit hungry and eager to understand exactly the internals and how it works my new to be fork.
#4
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Here is a little something that should be helpful. It pertains to motorcycle forks but the good mtb forks now use the same technology
"Conventional damper-rod forks provide spring damping by forcing oil through holes in a damper rod, located inside the fork tube. The problem with this arrangement is that the resistance of oil forced through these holes varies as the square of the velocity of the oil. Which means the damping can be set up just right for slow bumps but will nearly lock up over sharp ones. This phenomenon can't be detected by bouncing on the bike, but it's obvious when riding on a rough road.
Damping can be adjusted by varying oil weight, but that doesn't help with the sharp bumps.
Manufacturers of high-end forks solved this problem by eliminating the holes. Cartridge forks feature one-way valves comprised of a stack of shims held closed by a spring. Fork compression forces oil past these shims against the force of the spring - the amount of damping is determined by the number of the shims lifted off their seats by the oil pressure. Cartridge forks can be adjusted for good low- and high-speed damping.
For bikes (like my SV650) with damper-rod forks, there's a solution. Race Tech makes the Cartridge Emulator, which has a shim stack and spring just like in a cartridge fork. The original compression damping holes are drilled out to a much larger size, so they don't do anything, and compression damping is handled by the shim stack and its spring. The cartridge emulator sits on top of the damper rod, inside the fork tube.
Cartridge emulators have two advantages: improved high-speed compression damping, and the separation of compression and rebound damping adjustments. Rebound damping is set simply by changing the weight of the fork oil (same damping holes for rebound), then the compression damping is set by adjusting the spring on the shim stack.
This allows stiffer rebound damping with softer compression damping - which, as mentioned, works for both low and high speed bumps."
"Conventional damper-rod forks provide spring damping by forcing oil through holes in a damper rod, located inside the fork tube. The problem with this arrangement is that the resistance of oil forced through these holes varies as the square of the velocity of the oil. Which means the damping can be set up just right for slow bumps but will nearly lock up over sharp ones. This phenomenon can't be detected by bouncing on the bike, but it's obvious when riding on a rough road.
Damping can be adjusted by varying oil weight, but that doesn't help with the sharp bumps.
Manufacturers of high-end forks solved this problem by eliminating the holes. Cartridge forks feature one-way valves comprised of a stack of shims held closed by a spring. Fork compression forces oil past these shims against the force of the spring - the amount of damping is determined by the number of the shims lifted off their seats by the oil pressure. Cartridge forks can be adjusted for good low- and high-speed damping.
For bikes (like my SV650) with damper-rod forks, there's a solution. Race Tech makes the Cartridge Emulator, which has a shim stack and spring just like in a cartridge fork. The original compression damping holes are drilled out to a much larger size, so they don't do anything, and compression damping is handled by the shim stack and its spring. The cartridge emulator sits on top of the damper rod, inside the fork tube.
Cartridge emulators have two advantages: improved high-speed compression damping, and the separation of compression and rebound damping adjustments. Rebound damping is set simply by changing the weight of the fork oil (same damping holes for rebound), then the compression damping is set by adjusting the spring on the shim stack.
This allows stiffer rebound damping with softer compression damping - which, as mentioned, works for both low and high speed bumps."
#5
Part of the furniture
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thanks mate
#6
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Originally Posted by math2p14
More fork internal questions
#7
Still kicking.
Closed, over a year old.
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