5
1 DESIG
Inside the TTX GP
When the shock absorber moves
When the shock absorber moves, the fluid inside
is forced to flow through the compression valve
or the rebound valve, depending on the direction
of the movement, followed by going through
either the rebound check valve or compression
check valve and to the other side of the main
piston (figure 2 and 3). The piston rod displaces
the fluid into or out of the reservoir.
The reservoir
The reservoir is connected to the damping
system in a way that regardless of the direction
of the movement the reservoir will be connected
to the low pressure side of the main piston.
The compression and rebound valves
The compression and rebound valves have
three flow paths for the fluid, the bleed valve,
shim valve and the check valve.
The bleed valve (figure 1 center grey arrows)
is a small orifice giving a flow restriction by its
small size. In the shim valve (figure 1 black
arrows) the fluid pressure must deflect the thin
steel washers to open up the valve to allow fluid
to flow through. The check valve (figure 1 outer
white arrows) contains a spring preloaded shim
that opens easily for return flow of fluid when the
movement direction changes.
The bleed valve and the shim valve build up
the damping force. At slow stroke speeds the
amount of fluid going through the bleed valve
is higher. At a fast stroke the shim valve takes
care of most of the fluid flow. The check valve,
together with the bleed valve (since it can flow
both directions), handle return flow.
1
Basic flow during
compression stroke.
