Polaris 2003 Universal Snowmobiles - Manual (Page 61)

59
THE PERFECT FIT
M-10 Suspension
Before proceeding with the tuning of your M-10 suspension, you
should familiarize yourself with the following terms:
Description of M-10 Features
Long Travel - Refers to the over 10″ of REAL travel that the M-10 has
between the rear arm cross-shaft and the slide rail. this is the location
to measure suspension vertical travel. In the Edge Chassis, the rear axle
travel is 13.9”.
Biased Couple - Describes the linked relationship between the front
and rear arms of the M-10. When the M-10’s front arm contacts a
bump, the couple forces the rear arm to react instantly. This limits the
angle of incidence between the rail and bump as the rear arm crosses it.
the flatter this angle is kept, the less secondary reaction (kick) the rider
will feel, and better maintenance of TRACK TENSION can be attained
through the full 10″ travel.
Couple Blocks - Are the plastic sliding blocks located at the rear of the
rail. These pieces facilitate the M-10’s actual couple function.
Advanced Ride Control (ARC) - ARC geometry decelerates shock
and spring speed throughout compression travel making the shocks
very sensitive to sled speed. This enables large strokes to be used in
nearly all conditions, high or low speed, delivering huge benefits in
rider comfort.
On return travel, the shock speed or rate is increased, which in effect
delivers “RISING RATE” on the rebound stroke. The mechanical
advantage of the system over the stored spring energy is very high,
especially when compared with conventional systems. The result is
excellent control of the “kick” and normal return forces which FAST
has identified as being the most upsetting to the rider during travel over
rough conditions.
Full Range Adjuster (FRA) - FRA refers to the adjustable lower rear
shock attachments. Major adjustments in rider weights can be made
from 100 lbs. at the rear (#1 SOFT position of the slot) to 350 lbs at
the front (#4 FIRM position of the slot). Changing this location has
two effects on tuning. Moving the shock forward increases shock
speed, resulting in firmer damping on both compression and rebound.
It also increases the effect of the rear spring by displacing it further.
The adjuster is infinitely variable between those settings. Using a
9/16″ wrench, adjustments are made quickly and easily.