Hi,

Anybody use this system in his Trial bike ??

http://www.suspensionhfs.com/en/content/en/trial

It appears to be a simple Schrader valve in the top cap and we tried this system many years ago. A company called Goki also had a tube that connected the top caps together to equalize pressure between the two forks. The problem lies in the fact that the air heats up in use and exerts greater pressure, however, the fork damping fluid also loses viscosity with temp rise. The decreased fluid viscosity coupled with the greater spring/air rate causes a loss of damping control in fork action.

We found that the correct spring/preload combination along with the correct fluid quality/viscosity rating (and zero air pressure at full extention) gave the best results under most conditions throughout the whole Trial.

I've often thought about developing a Silicone based fork fluid as I understand that Silicone, unlike regular fork fluids, thickens with temp rise and that's why it is used in automotive cooling fan "clutches". I'm guessing that the Silicone fluid, however, would make setting the damping a little difficult as it is slightly compressable (and why DOT-5 Silicone is not used in racing brake systems as it makes for a "spongy" brake pedal).

Jon

It appears to be a simple Schrader valve in the top cap and we tried this system many years ago. A company called Goki also had a tube that connected the top caps together to equalize pressure between the two forks. The problem lies in the fact that the air heats up in use and exerts greater pressure, however, the fork damping fluid also loses viscosity with temp rise. The decreased fluid viscosity coupled with the greater spring/air rate causes a loss of damping control in fork action.

It's actually a self contained air spring which is used with a shorter compression spring.