"NO MAINTENANCE" VARIABLE AIR TANKS FOR FORKS

 TOO TECH RACING

TOO TECH AIR TANK ADVANTAGES 

SAFETY - The tank can not come loose and get caught between your forks and the triple clamps.

NO MAINTENANCE HASSLES - No oil to drain; bleed your accumulated fork air pressure any time.

CONSISTENT REBOUND ACTION - The check valve principle insures that all the air can get out of the tank and flow to the forks freely.  This insures that the rebound action operates without delay.

PRINCIPLES OF AIR TANK OPERATION ON A DIRT BIKE

 First some basics:

Motorcycle forks support the weight of the bike using a spring and compressed air. 

• The upward force generated by the spring is dependent only on how far the fork, thus the spring, is compressed.

• The upward force generated by the compressed air depends on where the oil level is set and how far the fork is compressed.  As the fork compresses, the air inside is compressed.  The rising air pressure pushes against the top of the forks and generates an upward force which adds to the spring force.

The spring force, the compressed air force, and the hydraulic forces determine how far the front-end compresses when hitting bumps and entering turns.  The suspension tuner sets the spring force and the hydraulic forces.  This leaves only the oil level to be tuned by the rider. 

• If the rider lowers the oil level (more air volume), the front will ride lower, turn better, feel plusher, BUT bottom more easily.

• If the rider raises the oil level (less air volume), the bike will ride higher, be harder to turn, feel stiffer, and reduce bottoming.

The Air Volume Tank allows the fork to perform like a large air volume (low oil) fork for turning and then switch to a small air volume (high oil) for jump landings and high-speed hits.  The airflow metering valve is the key to changing the effective air volume while you ride.

• The tanks work by adding a large volume of air to the compressed air system.  As the fork compresses slowly, the air in the fork flows slowly past the metering valve and both the fork and the air tank gain pressure together.  The fork responds as if it has a low oil level.

• If the forks move quickly (like landing from a jump) the air in the fork compresses quickly and tries to move quickly into the air tank.  The metering valve restricts the airflow into the tank.  This causes the pressure inside the fork to rise as if the bottle was not in the system.  The fork responds as if it has a high oil level.

• Adjusting the metering valve controls the rate of airflow between the fork and the air tank and thus determines the speed at which the fork action changes from "low oil level" to "high oil level".  
  • Wide open metering valve settings allow air to flow freely between the forks and the tanks so the forks respond as if the oil is low for all but the highest speed hits.
  • Very small metering valve openings minimize airflow between the forks and the tank so the forks respond as if the oil is low for only the lowest speed hits.
  • Further suspension tuning can be realized by adding or lowering the actual amount of oil in the forks.

Regardless of oil levels or metering valve settings, it is essential that the metering valve have a check ball that allows free flow of air from the air tank back into the forks.  This allows the fork rebound to be consistent regardless of metering valve openings or fork compression speeds.

YZ 450 / 250 View with number plate removed.

Note the "Flow Control Valves" where the lines connect to the at the bottom of the bottles.

Note the Quick Connect fittings at the top of the forks for easy disassembling.

CR 450F with 20mm offset triple clamps and Pro Tapers - View with number plate removed.

To move the bottle forward enough to clear the setback fork tubes and the fat handlebars, we used a 90 degree brass adapter and faced it forward.  The standard 90 degree bend stainless tube then angles in towards the center of the bike to connect to the tank.  As you can see, this arrangement creates a cradle for the tank to sit in.  This arrangement positions the tank lower and farther forward than the standard mounting position.  I think this arrangement would clear just about any handlebar mounting obstacle.

This Air Tank Kit sells for 200 dollars.  

We charge 40 dollars to drill and tap your fork caps to accept the adapters.  We tap them for free if the forks and shock are being revalved at the same time.

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