A progressive suspension device (1) for the rear wheel of a motorcycle,
includes a swinging fork (2) that has a central section (10) to which one
or two arms (8, 9) carrying a wheel (7) are connected. The suspension
device further comprises a spring-damper assembly (14) connected at one
end to a support (13) for the central section (10) of the fork (2), a
rocker or lever (15) having a first end (16), with axis (16a), pivoted in
seats (17) made in the engine crankcase (12) or in the motorcycle frame,
the lever (15) also having a second end (18), with axis (18a), connected
to the spring-damper assembly (14), A connecting rod (19) of adjustable
length (C) joins the fork (2) to the lever (15). The connecting rod (19)
comprises a first end (20) pivoted at an intermediate mounting point (21)
between the first end (16) and the second (18) of the lever (15), and a
second end (22) pivoted in a seat (23) made in the central section (10) of
the fork (2). At the lever (15), between the mounting point (21) where the
connecting rod (19) is pivoted and the axis (18a) of the second end (18),
there is an angle (.alpha.) that may be varied to adapt the suspension
device (1) to different progressive suspension needs.
