Rear Suspension Adjustments

Content Source: 2019 550 Indy 144 Owner’s Manual (9928872 R01) > The Perfect Fit Chapter

IMPORTANT

The Owner's Manual for this vehicle contains warnings, instructions and other information you must read and fully understand before safely riding or performing maintenance on this vehicle.Always follow the warnings and instructions in Owner's Manual.

Click the CONTENTS link above for the Table Of Contents, or download a full PDF of the Owner Manual in the Owner Support area of Polaris.com

Rear Suspension Adjustments

Rider weight, riding style, trail conditions, and vehicle speed all affect suspension action.

Each rear suspension can be adjusted to suit rider preference and deliver excellent performance for a given set of conditions. However, all suspension designs and adjustments involve a compromise, or trade-off. For example, a suspension set up for snowcross racing would provide a very stiff ride on the trail. A suspension set up for trail riding would bottom out harshly on a snowcross course.

Refer to the suspension setup label on your snowmobile, or your POLARIS dealer can provide the initial suspension setup information. Additional adjustments can be made after initial setup. Make adjustments to one area at a time so you can evaluate the change. For further assistance, your dealer can assist.

Suspension Performance Tips

Rider weight usually determines the position at which the spring preload should be set. However, this may vary with riding style. With a little experimentation, each rider can find a preferred set-up. These adjustments are easy to make, involve very little time or effort, and greatly affect the ride.
In deep snow, a new rail slide will offer improved performance over a worn rail slide. It can also improve top speed.
When riding on ice or hard-packed snow, adding a set of bogie wheels to the rail may enhance the snowmobile’s performance. Bogie wheel kits are available from your dealer.
POLARIS offers track kits for improved flotation in deep snow. See your dealer for assistance.

TIP

Keep the suspension pivot points lubricated. This will reduce moisture and rust build-up and ensure proper function of the suspension components. Grease rear suspension pivots before adjusting the rear suspension.

Track Tension

Track adjustment is critical for proper handling. Always maintain correct tension and alignment. Refer to the track tension maintenance section of this manual.

Rear Track Shock Spring (144)

Measure the rear track shock spring length and adjust to the appropriate length based on rider weight. Include passenger weight (if applicable) and all riding gear, accessories and cargo weight in the calculation.

WARNING

Allow a passenger to ride only on models equipped with a passenger seat.

Securely elevate and support the rear of the snowmobile to remove the weight from the suspension.
Use a tape measure to measure the spring installed length between the two spring retainers.
Refer to the chart on the next page to determine the correct spring length for rider weight. If adjustment is needed, clear away any snow or ice trapped within the spring or threads.
Using a spanner wrench, rotate the spring to adjust length.

NOTICE

Never adjust a spring beyond the maximum length shown in the chart. Adjusting beyond maximum adjustment will cause the spring to bottom and result in damage to your rear suspension.

Adjust the rear track shock spring per the chart below.

REAR TRACK SHOCK SPRING (RTSS) SET-UP (Standard Spring) Measure spring length with suspension off the ground
Rider Weight(including all riders, gear, cargo, & accessories		Model	Installed Spring Length(rear suspension off the ground)
Shaded cells indicate factory settings.
< 160 lbs	< 73 kg	550 INDY Adventure/Voyageur/LXT	11.125"	28.2 cm
		550 INDY 144
160-220 lbs	73-100 kg	550 INDY Adventure/Voyageur/LXT	10.75"	27.3 cm
		550 INDY 144	10.5"	26.7 cm
220-280 lbs.	100-127 kg	550 INDY Adventure/Voyageur/LXT	10.5"	26.7 cm
		550 INDY 144	10.125"	25.7 cm
280-340 lbs.	127-154 kg	550 INDY Adventure/Voyageur/LXT	10.125"	25.7 cm
		550 INDY 144	9.75" Maximum Adjustment	24.7 cm Maximum Adjustment
340-360 lbs.	154-163 kg	550 INDY Adventure/Voyageur/LXT	9.875" Maximum Adjustment	25 cm Maximum Adjustment

Initial Spring Preload Setting (Sag Method) (155)

To set up the rear suspension torsion spring preload, measure the distance between the ground and rear bumper. This is measurement X.

Take the first measurement with no rider and with the rear suspension at full extension.

TIP

The rear bumper may need to be lifted upward slightly to fully extend the suspension.

Next, have the rider drop down hard on the seat and bounce up and down several times, collapsing the rear suspension. With the rider seated, measure the distance between the ground and the rear bumper at the exact location used for measurement X. This is measurement Y.

To determine sag, commonly referred to as ride-in, subtract measurement Y from X (sag=X-Y). Adjust sag by rotating the torsion spring preload cams located on the rear torque arm. See illustration on Torsion Spring Preload.

The ideal amount of sag for this rear suspension is four inches (10.2 cm) (X-Y = 4 in./10.2 cm).

If the rear suspension rides in less than four inches or more than six inches with the torsion spring preload cams at their maximum range of adjustment, optional torsion springs (softer or stiffer, respectively) may be required. This is only an initial setup, and final spring preload may vary based on rider preference and riding conditions.

Torsion Spring Preload (155)

To adjust rear torsion spring preload, rotate the three-position cam using the engine spark plug tool. Different rate torsion springs are available if a firmer ride is desired. See your dealer for more information.

The following information is provided only as a guideline to be used for initial suspension set-up. Your set-up may vary based on your desired riding style.


Soft (long end of cam to front)	Medium (short end of cam up)	Firm (long end of cam up)