Newbie Handling Question

[twowheels]

Originally Posted by Clay

The tri shaped knob is called a PFP adjuster. Don't know what it stands for.

PFP = Progressive Floating Piston

I've been trying to contact Italy through my Tenneco contacts, but for now the internals are a mystery.

[Clay]

Originally Posted by twowheels

PFP = Progressive Floating Piston

I've been trying to contact Italy through my Tenneco contacts, but for now the internals are a mystery.

I've asked the US Zoke guys. So far the crickets are still chirping.

[GMP]

I wonder if Les has seen any yet. Progressive floating piston sounds just like a piston shock resovoir design to me (Ohlins, Sachs, WP) vs a bladder design, with a spring behind it instead of compressed nitrogen. The concept of CC forks is simply to keep the oil clean and from becoming mixed with air, prevent cavitation, and provide more consistant damping. My biggest question is how hard is it to service in the garage for the average guy, and what if any special tools are required.

[Clay]

I got this back from my contact at Marzocchi:

PFP system:
The PFP (Progressive Floating Piston) System is a new adjustment on our USD48 fork and it's patented because our competitors don't have this
feature. PFP System is an external adjustment, on the caps of both sliders, in addition to the compression and rebound adjusters. Its aim is to modify
the pressurization level of the sealed cartridge in order to increase the range of the hydraulic load. Through the PFP System the Tenneco Marzocchi
USD48 fork is the fork with the biggest hydraulic range in the market using the external adjustments

So rather than changing oil flow like the compression and rebound clickers do, the PFP valve increases the pressure of the sealed/closed cartridge.

Clay

[GMP]

I think I get what it is now. Its like a preload adjuster for the cartridge spring. Clay, have you tried adjusting yours? It would be very cool to set the fork up plush enough for rocks and be able to dial in more resistance for the faster stuff.

[rxmx]

Due to work, won't be able to play with the forks for about 4 days. I had to back off the shock spring preload to 3.5mm to get 110mm sag, with stock 5.2 spring (Ohlin shock)...I weigh 160# empty, only 2hr on bike. Can I expect the spring to "loosen" up after some time, seems a bit stiff for a 5.2......?

[Clay]

Originally Posted by GMP

I think I get what it is now. Its like a preload adjuster for the cartridge spring. Clay, have you tried adjusting yours? It would be very cool to set the fork up plush enough for rocks and be able to dial in more resistance for the faster stuff.

Jeff Melik has prolly played around with this more than anyone. I will ask him to jump in on this.
I haven't ridden anything fast yet so I haven't had an opportunity to try it. I'm gonna do some hare scrambles in the next few weeks so I may give it a try.

[Jeff Melik]

The pfp adjuster is really a lot more simple than it seams. By adjusting it in or out you are changing the ammount of force that is on the piston in the chamber. Basically by tightening the adjuster you are causing the piston to resist allowing the oil to pass through the valve and into the chamber. It is the exact same setup as a kyb fork accept that there is an external adjuster. On a kyb you can change the spring rate or ad shims to achieve the same thing. Stock setup on a kyb is with zero preload on the chamber spring. Thats what makes the zokes so good is that there is no disassembly required for adjustment.

As far as actual settings go my standard setting is all the way out. For more open stuff or moto ill add a turn or two. I tried a softer main spring rate in hopes that i could add some turns to make up for the lighter springs but there is a threshold with the pfp where it will start to deflect because you are esentially stiffening the valving not the spring. My recomendation is to use whatever spring you would normally use and start with the pfp all the way out. Id only use the pfp if you need a little more botoming resistance.

Hope this clears some stuff up and i didnt add to any confusion.

[twowheels]

Here's a shot of the famed KYB SSS compression assembly.

From right to left: The pressure spring can be seen under the cap, and then there is the nylon piston, and finally the compression valve assembly. Essentially when the fork compresses oil is forced through the valve assembly (on the left side) into a chamber stopped by the nylon piston. As more oil is forced through, the piston can move until the pressure is equalized by the spring.

Analogously the PFP system gives you the ability to increase or decrease the stiffness of the pressure spring.

Here's a shot showing the three-pointed PFP adjuster in the center of the fork cap, with the standard compression adjuster in the center of that.