Page 4 - Microsoft Photo Editor - FLYER2 FRONT.jpg

Compression phase:When at rest, the pressure in air chamber A and oil chamber B is equal. When load is applied and compression takes place, the oil in chamber B pushes its way through a special patented valve into chamber A, causing the air in this chamber to be compressed. Rebound phase:When pressure on the unit is released, the compressed air in chamber A expands, pushing and forcing the intruding oil back into chamber B through a smaller rebound exit channel.Asymmetric ratio:The compression-rebound damping ratio is asymmetric – that is, weak in compression and strong in rebound. This ensures a controlled return of air chamber A to its original position, and ensures that the wheel of the motorcycle itself follows the contour of the road surface as closely as possible, for superior comfort and handling.Chamber AChamber BWHY IS AIR COMPRESSION SUPERIOR TO SPRING COMPRESSION?One of the advantages of air compression over mechanical spring compression is the fact that air compression is not constant or linear, but hyperbolic – that is, air compression develops progressively more resistance as pressure on it increases.THE LIMITS OF THE CONVENTIONAL SPRING UNIT:Any spring-based shock absorber has what is termed a PRE- LOAD. This is the lower stress limit below which it does not register ANY shock. Impacts below this limit are transmitted directly to the rider – the suspension effect is virtually non-existent. Similarly the spring shock absorber has a maximum load, above which the spring becomes fully-compressed, and again renders the suspension virtually useless. This produces the ”bottoming” effect when the mechanical spring coilbind.LINEAR COMPRESSION:The compressing action of a conventional coil spring is LINEAR, because the force required to bend a spring possessing a specific poundage always remains the same,whether the spring is at the bottom or near the top of its compression phase. Because of these factors the action of a spring is represented on a graph as a STRAIGHT LINE.VARIABLE COMPRESSION - THE ABILITY TO ADJUST TO ALL CONDITIONS: Because the Fournales utilises air compression instead of mechanical spring compression, its compression performance on a graph is represented as hyperbolic instead of linear – meaning that the suspension becomes firmer as pressure on it increases, describing a hyperbolic curveinstead of a straight line.In this way the Fournales units canbe said to possess variable suspension with the air in chamber A (see diagram) providing changing resistance under varying load, as opposed to the constant resistance of a coil spring compression. While the spring unit always reacts to shock according to its pre-set limits, the Fournales is self-adjusting through a complete range of conditions – from the smoothest tarmac to the toughest Australian road conditions and from 1 up riding all the way to two up and two up with heavy luggage loads, including side-cars and touring trailers.WHY THE FOURNALES ACCEPTS AND ABSORBS EVEN THE SMALLEST ROADSHOCKS:As mentioned earlier, the mechanical coil spring shock absorber has a pre-load limit below which it has NO absorption qualities. This failing is overcome by the Fournales, which has a special feature allowing it to react to even the most minor road irregularity. A small internal spring located between the air and oil chambers pulls the air chamber down slightly at rest, causing the air pressure in the upper chamber to fall fractionally below normal pressure. This has the effect of increasing the threshold of sensitivity of the unit, and ensures that all shocks occurring below minimum load are registered and absorbed, The benefits of this feature – unique to Fournales – are clearly illustrated in the following graph depicting the relative performance of the Fournales and other types of shock absorber. Basically the Fournales unit is unique by having NO spring pre-load.