Snowmobile Polaris (2006 year). Manual - part 57

11.10

REAR SUSPENSION

M-10 SUSPENSION

M-10 OVERVIEW

The FAST M-10 rear suspension has been designed and set up 
to deliver a soft ride under average riding conditions. Rider 
weight, riding styles, trail conditions, and vehicle speed each 
affect suspension action.

The suspension can be adjusted to suit rider preference and 
deliver excellent performance for a given set of conditions. It 
should be noted, however, that suspension adjustments 
involve a compromise or trade off. A machine set up to 

perform well in the moguls would not suit the preference of a 
groomed trail rider.

M-10 ADJUSTMENTS

• Full Range Adjuster (FRA)

• Threaded Pre-load adjuster

• Rear Compression Spring Adjuster

• X-Over Tube Length Adjustment

IMPORTANT: The M-10 rear suspension has been 
designed to be very sensitive to rider weight. 
Changes in rider weight of 25 lbs. or more may 
require appropriate changes in FRA settings.

M-10 TERMINOLOGY

• Couple Blocks: Plastic blocks located at the rear of 

each rail. Blocks facilitate the couple function.

• Full Range Adjuster (FRA): FRA refers to the 

adjustable lower rear shock attachments. Changing the 
FRA location has two effects on tuning. First, moving 
the shock forward increases shock speed, resulting in 
firmer damping on compression and rebound. Second, 
it also increases the effect of the rear spring by 
displacing it further.

• Sag Settings: The difference in rear bumper height 

from the sleds fully extended position to its lower 
height with the rider seated on the sled.

FTA

RTA

Coupler Block

FRA

X-Over Tube
Pre-Load Adjuster

M-10 SUSPENSION

11.11

REAR SUSPENSION

M-10 ADJUSTMENTS

The primary adjustment on the M-10 suspension is the Full 
Range Adjustment (FRA). Adjusting the FRA will have to 
MOST effect on rear suspension performance.

Polaris recommends that you allow between 25 to 200 miles 
for the suspension to break in before performing any 
adjustments to the suspension.

This chart is a guideline to be used for initial suspension 
setups. Your setup may vary based on your desired riding 
style.

*=You may prefer an optional rear track middle spring 
retainer, see Table Table 11-4.

M-10 FRA INITIAL SET UP REFERENCE

The FRA setting is the primary rear suspension adjustment. It 
will have the MOST effect on the rear suspension 
performance. To adjust the FRA:.

1.

Refer to the initial set-up reference chart (see Table 11-
2and Table 11-3) to determine the desired FRA position.

2.

To adjust, loosen the hex bolts (A) attaching the rear lower
shock cross shaft to the rail beam.

3.

Using a 9/16" wrench, loosen the jam nuts (B) on the
preload bolts.

4.

Adjust the preload bolts (C) to the desired FRA position.

5.

Tighten the jam nuts.

NOTE:  Make sure the preload bolt contacts the slide 
block before tightening the jam nut.

6.

Tighten the hex bolts and torque to 35 ft. lbs. (47 Nm)

NOTE:  When the M-10 suspension is new, it will take 
from 25 to 200 miles (40-300 km) to properly break in 
the springs and shocks, at which time the 
suspension will be softer and may require FRA re-
adjustment.

Table 11-2: M-10 128

Rider weight with gear 
(lbs.)

Suggested FRA Range 
(Lower number is softer)

Under 100

1 to 1 1/2

100-150

1 1/2 to 2

150-200

2 to 2 1/2

200-250

2 1/2 to 3

250-300

3 to 3 1/2

300-350*

3 1/2 to 4

Over 350*

4 to 5

Table 11-3: M-10 136

Rider weight with gear 
(lbs.)

Suggested FRA Range 
(Lower number is softer)

Under 100*

1 to 1 1/2

100-150*

1 1/2 to 2

150-200*

2 to 2 1/2

200-250

2 1/2 to 3

250-300

3 to 3 1/2

300-350

3 1/2 to 4

Over 350

4 to 5

A

B

C

11.12

REAR SUSPENSION

M-10 REAR SPRING PRELOAD

If FRA position alone does not allow the setup of the proper 
amount of sag, the center retainer of the rear track shock can 
be replaced with optional retainers to adjust the preload and 
change the sag. 

NOTE:  Whenever ordering any of the retainers 
listed in the chart, always order the retainer insert as 
well. The insert is not removable once installed, so a 
new insert is needed when installing a new retainer.

M-10 SKI PRESSURE

Ski pressure is set at the factory to 
deliver the optimum balance between 
ride and handling. If a rider prefers 
more ski pressure for improved 
steering performance, adjustments 
can be made to the front limiter strap 
and front arm mount.

1.

Determine if the rider prefers
comfort or control. Lean toward
the #4 setting for comfort and
toward the #3 setting for
aggressive riding.

2.

For full hole adjustments, remove the 5/16" nut and flat
washers from the lower attachments of the limiter straps
and relocate the straps to the desired position (i.e. move
from position 4 to 3). Replace the nut and washer. Tighten
securely.

3.

For half-hole increments (such as 3/4), the limiter straps
have slots at the upper pinch bolt. These slots allow the
bolts to be loosened (rather than removed) for half-step
adjustments. Re-tighten the pinch bolts.

4.

There are also two front arm mounting holes in the slide
rail that can adjust ski pressure. The lower hole (A)
increases ski pressure while the upper hole (B) decreases
ski pressure.

NOTE:  By design, the BIASED COUPLE design of 
the M-10 suspension displaces the rear arm as the 
front arm is compressed. This means that when you 
raise the front limiter strap, at some point you will 
collapse the rear suspension arm, which will affect 
SAG height and reduce rear suspension travel.

WIDETRAK SUSPENSION

WIDETRAK REAR SPRING ADJUSTMENTS

Rear spring adjustment is primarily a control for riding 
comfort. To check for the recommended settings:

1.

Lift the rear of the machine to relieve the rear springs.

2.

Slowly lower the machine and measure the distance
between the ground and the running board.

3.

Without letting the suspension settle, the rider should
carefully mount the snowmobile.

4.

Measure the distance between the ground and the same
spot on the running board. The difference between the two
readings should be approximately 1 1/2” (3.8 cm). If the
difference is greater than 1 1/2” the rear spring should be
adjusted equally on both sides until the desired 1 1/2” drop

Table 11-4: Optional Retainers

Retainer insert 

Part Number

Retainer part 

Number

Preload

Sag

5436109

5135077 (std. 

on M10/128)

Least

Most

5134923

Middle

Middle

5135080 (std. 

on M10/136)

Most Least

1

4

2

3

2

3

4

A

B

A

11.13

REAR SUSPENSION

is obtained.

Compensating adjustments for heavy or light drivers or cargo 
loads can be made by adjusting the rear spring eye bolt (A) 
length. Adjust spring tension so there is equal tension on the 
long leg of each spring.

NOTE:   Rear spring settings will affect ski-to-ground 
pressure. If ski pressure is too light it may be 
desirable to tighten the rear springs for an increase 
in ski-to-ground pressure.

RAIL SLIDER

RAIL SLIDE WEAR LIMIT

Hi-Fax replacement on all Polaris models is similar. When any 
area of the Hi-Fax is worn to 1/8" (3 mm), it should be 
replaced. This will save wear on other vital components. The 
slide rail is designed to operate in conditions with adequate 
snow cover to provide sufficient lubrication. Excessive wear 
may be due to improper alignment, improper track adjustment 
or machine operation on surfaces without snow. Replace Hi-
Fax when worn down to 7/16".

RAIL SLIDE REMOVAL

1.

Remove the rear suspension.

NOTE:  Some models may allow the rail sliders to be 
removed by sliding it through track windows with 
the suspension mounted in the machine.

2.

Remove front rail slider retaining bolt, located at the rail
tip.

3.

Use a block of wood or a drift punch and hammer to drive
the Hi-Fax rearward off the slide rail.

4.

With the rail slider at room temperature, install a new rail
slider by reversing steps 1 - 3.

NOTE:  Lightly coat rail slider track clip area with a 
lubricant such as LPS2 or WD-40 to ease installation.

RAIL SLIDER BREAK IN

After installing new rail sliders they must be “broke in” for 
longer life and better wear patterns. When performing the 
breaking in procedure ride the sled on a surface that has 
adequate snow conditions with deeper snow nearby. Run the 
sled on the adequate snow surface and dip into the deeper 
snow every so often.

REAR SUSPENSION REMOVAL / 
INSTALLATION

REAR SUSPENSION REMOVAL

1.

Support the rear of the machine so that the track is off the
floor.

2.

Loosen the rear idler bolts and move the rear idler shaft all
the way toward the front of the suspension. This will help
give you more room to work with while removing the
suspension.

3.

Remove the four suspension bolts that hold the rear
suspension to the chassis.

4.

Place a protective mat on the floor and tip the unit over on
the left side, supporting the sled on the end of the
handlebar.

5.

Remove the suspension from the tunnel.

REAR SUSPENSION INSTALLATION

1.

With the unit on its left side, place the suspension in the
tunnel and carefully turn the unit upright.

2.

Support the rear of the unit.

3.

Lower the unit so that you can start all four of the new
suspension mounting bolts.

IMPORTANT: It is strongly suggested that you 
replace the rear suspension mounting bolts with 
new bolts. These bolts are treated with a special 
locking agent. Use of any other locking agent may 
cause damage to the suspension or suspension 
hardware.

4.

Torque the rear suspension mounting bolts to the correct
specification,

 

see “MOUNTING TORQUE

SPECIFICATIONS” on page 11.2.

5.

Align the track guides/clips with the suspension rails.

6.

Adjust the rear idler to achieve the correct amount of track
sag, see “TRACK TENSION” on page 3.21.