suspension guru's I have a question about gas charging

You have same ring on floating piston to seal air from oil.

 

see post 77

 

It all depends on the type of fork.

 

Correct, I seen Matris puts O-ring there. Not sure it would hold to pressure.
But in general most are not sealed and you can't pressurize cartridge alone.

 

Ohlins also installs an o-ring or an x-ring on their cartridges, but their gas charged fork is seal at the cartridge head.

Traxxion's gas charged cartridges are sealed too.

Also twin chamber motor cross forks have seals on the damper rods. They are like gas charged forks with out the gas as it is a sealed unit using its own oil while the fork uses its own oil. Very good at keeping the damping oil cleaner longer.

 

would you think ohlins avoids making the more inexpensive gas cartridge like a penske or AK because they make the FG superbike series ?

They make a 25mm cartridge that in effect makes a stock for perform like a R&T without all the billet and fancy fork tubes but still sell a ton of R&T ,I would think a good ohlins gas charged cartridge at the prices Ak and penske are selling would not effect the sales of the full gas forks too much .

 

My ohlins forks don't have o-ring there, older model.

 

The older R&T forks are junk, basically just for looks. They were made in China and had shit internals. The only good thing about them was the tubes were TiN coated for less stiction.

The newer R&T forks have the same parts as the Superbike cartridge kits.

What model forks are they?

 

good to know ,I also see that ohlins has gone to the model dedicated solid bottoms in the last few years instead of the bolt on caliper mounts.I always wonderd why they went with the bolt on mounts when they must know the flex that can cause .obviously a cost saving thing.

 

old ones, fg43 I think.

 

Those are older R&T forks and they have an o-ring on the shaft.

 

Ok I will stop asking questions and repeating myself ,because I am obviously over my head when it comes to the details of suspension .So riddle me this ,take a cartridge fork,seal it with an x-ring at the rod or whatever the best place is to seal it from the oil and air at the top of the fork ,add a remote gas charged res into the lower part of the cartridge for the oil to expand to under compression with a sealed seperating piston ,can you conceivably have gas charged forks ?

and thanks for taking the time to school me on this stuff i learned a shit load.

I'll hang up and listen for your response .lol

 

They have O-ring for top out, that is about it.

 

any answer to post #91 ?

 

Yes, do it

 

I was trying to keep things very generalized in regards to the seal (or lack thereof) at the top of the cartridge.

 

It is good way to pile up pages
I think forks are pita, they should put swingarms and shocks there

 

Yes.

You need to learn where the oil goes before you go out and invent your own gas charged fork cartridge.

 

Im definately not trying to invent a cartridge Im just wondering if one can be made from existing components even if its just theory .

 

There are several distinct advantages to a gas pressurized damper when compared to a convention open bath styled fork cartridge. An open bath fork cartridge pumps oil into and out of itself from the main body of the fork. There is a great deal of contamination in the oil, such as Teflon from the bushings, spring steel flaking off of the spring, aluminum from screwing the cap onto the steel tube, and then general oxidation contamination from all of the parts rubbing together. All of this contamination from the main body of the fork is then circulated into the sensitive valving of the damping unit. Invariably, it manages to get stuck in the valving shims resulting in a loss of damping force, and frequent maintenance to maintain top performance.

As far as the performance itself, an open bath cartridge is constantly blending tiny air bubbles into the oil and a loss of damping force results over the course of a race. More air equals more fade. Also, there is a noticeable change in damping force as the fluid warms. All damping units used in motorcycle roadracing are velocity dependent. That means they have to be moving in order to create any damping force. Each time the wheel stops moving and has to go the opposite direction, it has no damping force. If the wheel doesnt move far enough to build damping force before it is stopped again and asked to move in the opposite direction, it can spend a fair amount of time with very little, if any force at all controlling the wheel. The biggest drawback to an open bath cartridge is the cavitation that results over sharp bumps, ripple bumps, and braking zone stutter bumps. Since the oil is not under any pressure, it is very easy for a sharp bump to move the wheel at a speed that the damping unit cannot react to. When this happens, an internal vacuum in the cartridge forms creating havoc for wheel control, which results in a loss of traction. Gas-charged damping units are assembled, bled free of air, and then pressurized. They become a sealed environment that contamination cannot enter. Since the oil is under pressure, it doesnt foam, and cavitation is completely eliminated. As a result, damping force remains consistent over the course of a race.

The result in performance are tremendous. Since pressurized damping units offer more instantaneous damping force, greater wheel control gives the rider dramatically improved feedback from the tire. Since cavitation over bumps is eliminated, most riders are shocked to find that the bumps are gone not just diminished gone. All of these factors combine to improve rider confidence and control. This beyond question, lowers lap time


well that answers a big one,the air is bled off