Finding the Balance
Many riders suffer through or endure poor riding snowmobiles even when
they don't have to. They think that it is just a poorly made sled.
This may be true of some snowmobiles, but for the most part, it is
because their snowmobile suspension is not set up properly for them.
Their suspension is either not providing enough weight transfer or is
providing too much. Adjusting the ride height of the snowmobile's
suspension to provide the best weight transfer can make your sled ride
like it is on rails.
Snowmobile manufacturers try to set up their snowmobile suspensions to
work well for the average rider, but they just don't have the
resources to set them up for each individual rider. The problem with
that is many riders do not fall into the category of the
"average" rider. This is the very reason that since
the mid-1990's almost all snowmobile suspensions were made to be
adjustable. You have the ability to tweak different components of the
suspension to make it perform differently. The key to a well riding
snowmobile is finding the balance of weight transfer that is right for
you as a rider.
In order to adjust the ride height of sled, you should first have a
basic understanding of all the suspension components and what their
function is. Once you know what each component does, you can make the
adjustments to each component make your snowmobile suspension react the
way that you want it to. Below is a list of the moving components that
can be found on most snowmobile suspensions since the 90's.
Independent front suspensions, whether it's a-arm or
trailing arm based, have front/ski shocks control the travel and
dampening of the front suspension. Most ski shocks have a coil
over spring that can be adjusted by turning the retaining collar.
The tighter the spring is set, the stiffer the suspension will
be and vice versa for a loose set shock spring. The stiffness of
the spring will also affect the amount of ski pressure. More
stiffness will reduce the amount of ski pressure, while
decreased stiffness will provide more ski pressure.
The moveable rear arm is what connects the rear of the skid
frame to the snowmobile tunnel. The rear shock is attached to
the rear arm to control its movement and damping ability. The
rear shock is not adjustable, but a rear shock that has failed
will cause the snowmobile to be too "soft" and
will bottom out in the rear with ease.
Limiter straps are attached to the front arm and the front of
the skid. Their purpose is to limit how far the center shock can
extend, which in turn affects the weight transfer of the
snowmobile suspension and the amount of ski pressure. The
tighter the strap is, the less amount of weight will be
transferred. Limiter straps have a line of holes that they can
be tightened or loosened to.
For the exact procedures on how to adjust these components on your
particular snowmobile, consult your owner's manual.
Now that you have a basic understanding of the main moving parts of your
snowmobile, you can now make adjustments to set it up perfectly. The
first thing that you need to do is set your sled back to its baseline.
This is where the suspension is absolutely balanced. Once you do this,
you can then make minor adjustments to customize the suspension to fit
you and your riding style. Follow the steps below to balance your
The first thing that you will need to do is to set the pre-load
of the front and center shocks. Pre-load is the measurement of
the difference between the spring's free length compared to
its installed length. In order to measure the pre-load, you must
either lift the snowmobile off of the ground or measure with the
shock uninstalled. Next, back the spring retainer off until the
spring is no longer being compressed. Measure the length
of the spring to get the free length of the spring. Now that you
have the free length of the spring, turn the spring retainer to
compress the spring to somewhere between 5-10mm. This difference
will be the pre-load setting. It's important to make note
of your measurements so that future adjustments can be made
Limiter Straps & Coupler Blocks-
For this step, the snowmobile should be sitting flat on a hard,
level surface with nothing under the skis or track. Now check
the limiter strap for tension. The limiter strap should be
completely free of any tension. This will ensure that the weight
will be distributed from the front and rear suspension. If there
is extra play in the strap, you can tighten it up to remove the
slack. Next, set the coupler blocks to the thinnest position
facing the rear stop for a neutral setting.
Even Weight Distribution-
With the previous steps done, you can now check to make sure the
weight of the snowmobile is being evenly distributed from front
to back. The skid of the rear suspension should be lying flat on
the ground. Loosen the limiter strap if the front of rail is off
of the ground. If the rear is off of the ground, you may have to
adjust the preload on the front shocks to stiffen the front end.
Front Free Sag-
The amount the suspension compresses under its own weight is
called free sag. For snowmobiles, there is no specific
measurement, but a number to shoot for is to have the front free
sag be about 20% of the total amount of suspension travel in the
front. To check the front free sag, you will need to lift the
front bumper to the point that the shocks are fully extended and
then measure the height of the bumper. Next, set the sled down
and compress the shocks by applying pressure to the front bumper
and then release. Do this a couple of times to settle the
suspension. Now measure the height of the bumper. The difference
between the two measurements will be the amount of free sag in
your front suspension. You can adjust the pre-load of the front
shocks until you reach your desired amount of front free sag.
Rear Free Sag-
Check the free sag of the rear suspension by lifting the back
off of the ground by the bumper and then setting it back down.
When set back down, the suspension should sag a bit. If it does
not, then the shocks are at full extension. You can reduce the
amount of pre-load on the center shock to give the rear
suspension more free sag.
You may need an extra set of eyes to check the loaded/race sag.
Loaded/race sag is the amount of sag the suspension experiences
when it has a normal riding load on it i.e. rider, luggage and
gear. With the normal load on the snowmobile, the coupler blocks
should be centered between the stops. If it is not, you will
have to adjust the torsion springs to another setting.
Now that you have gone through these steps, you have now established a
good baseline for your snowmobile suspension. The ride height and weight
transfer should be well balanced. The next step is to ride the
snowmobile to test it out. Because every rider is different, you may
have to make further adjustments to the suspension to achieve the
results that you desire. Below are some of the common problems and what
you should adjust to remedy them.
Inside Ski Lifts in Corners
Your snowmobile's front ride height may be set too high. To fix
this, try reducing the amount of pre-load on the front shock springs.
This will help to lower the center of gravity to make the snowmobile
less tippy in corners.
Diving In Corners/Body Roll
This is the opposite of the inside ski lift. While cornering, the
momentum of the snowmobile with over compress the inside front shock.
To fix this, try adding more pre-load to the front shocks to stiffen
Ski Lift While Throttling Out of a Corner
If the ride height is set to be balanced from front to rear, you can
adjust the coupler blocks so that the system stops sooner during the
transfer. More load will be left on the skis to keep them down as you
apply the throttle.
Rear End Drops and Raises with Ease
The most common cause of this is the ride height being out of balance.
If you have the ride height set properly, then you can rule out other
possible problems. It could be that a shock is blown or the torsion
spring is broken. These problems are very rare though and should only be
considered after the ride height settings have been reevaluated.
Check Article on How to stop Darting Here- http://powersports-blog.denniskirk.com/5177/snowmobile/how-to-stop-snowmobile-darting-and-tracking/