It can surely be mind-boggling to try and decipher all about suspensions of your snowmobile on your own. To make it easier for you, we bring you this article where you will get to learn everything that you need to know about snowmobile suspensions.
Purpose of Snowmobile Suspension
The purpose of snowmobile suspension is to support the rider to go into any aggressive terrains fearlessly and comfortably as it makes the snowmobile more predictable. It helps to distribute the weight, adjust the height, and also affects the rebound and compression rates. Suspensions are built to work more effectively within a specific range of their travel and this may vary according to different snowmobile companies and brands.
With the help of suspension, preferred ride height can be set using the springs, and this is what serves as the primary purpose of the springs. Their goal is to return the snowmobile to your pre-set height after the snowmobile jumps off the set height on bumpy terrains.
The suspension of a snowmobile can either make or break your ride. It makes your ride neither too bumpy nor too stiff; all it takes is a correct adjustment of the setting of the suspension of your beast.
When the snowmobile is first bought, it is set and adjusted for an average person to ride it. The purpose of the suspension is to transfer the weight equally around the sled, and not all persons weigh the same. Hence, an average adjustment is not enough. Therefore, setting up the suspension according to the rider’s preference is advisable.
How Does Snowmobile Suspension Work?
To know how a suspension works, it is vital to know about the components that go into making one and what each part contributes to the working of the suspension. Below are the names of a few moving components.
Every independent front suspension, irrespective of its arm base, has front/ski shocks that control the travel and dampening of the front suspension. There is a coil-over spring in most suspensions that can be adjusted by simply turning the retaining collar. As you tighten the spring, the stiffer the suspension gets, and the more you release it lose, it gets softer. The stiffness affects the ski pressure, and more stiffness reduces ski pressure, while decreased stiffness provides extra ski pressure.
The rear arm is moveable and connects the rear of the skid frame to the snowmobile tunnel. To control its movement and damping ability, the rear shock is attached to the rear arm. The rear shock cannot be adjusted, but if it failed, it can cause the sled to be too soft.
This is the initial shock that is responsible for the majority of the work. It takes all of the hits first from every bump on the way. It also distributes and controls the weight that contributes to traction at speed.
Torsion springs are the ones that are attached to the rear arm and are attached to the suspension skid. The adjustment of this helps in adjusting the weight transfer from the rear to the front. They aid in distributing weight throughout the snowmobile.
This is present in most modern snowmobile suspensions that can be adjusted behind the rear arm. They control the weight transfer by putting a stop at the movement of the coupling system.
Different length sides of the blocks control the length of movement of the arms. The shortest side of the block provides the softest ride, and the longest side of the block offers the stiffest ride. The weight transfer allowed by the blocks is also responsible for the snowmobile’s steering.
To the front torque arm of the suspension skid, the center shock is connected. The front arm connects the front of the skid to the chassis, which is the base frame of the snowmobile and is moveable. The center shock controls the damping ability of the front arm, it also affects the movability. Center shocks help the shock to rebound after being compressed.
To the front arm and the front of the skid are attached the limiter strap. The purpose of which is to limit how far the center shock can extend, which in return is responsible for the weight transfer of the sled suspension and the ski pressure. A tighter strap means less amount of weight will be transferred.
How to Remove Suspension from a Snowmobile
For installing a new suspension, it is required to remove the existing suspension. To do so, put the rear of the snowmobile upon a stand or a lever lift. If you don’t have those, a rope can be tied down or hooked to the back bumper and tied to something on your roof, which is strong enough also works well.
If you are using a stand, it is advised to put blocks under the track, so the suspension doesn’t fall when the bolts are removed. On the other hand, if you are using a tiedown or a rope, just slightly lift the sled.
The next step is to loosen the rear track adjusters and remove the rear bolts by holding the suspension to the tunnel or chassis.
Now remove the two bolts that are holding the front of the suspension to the chassis. At this point, the back can be raised higher for room to work. Then you can slowly work the suspension out, starting with the back. Once you have it clear out of the track in the back, it can be pulled straight out.
How to Install the Suspension in a Snowmobile
Firstly, remove the top pin holding the shock. Then once that is done, the limiter strap needs to be undone. The next step is to loosen the rear axle bolts and the track adjusters full off.
At this point, the sled needs to be raised with anything equivalent to a hoist. The rear suspension bolts now need to be undone and also the front suspension bolts. Do remember where the bolts were mounted. Now the suspension arms need to be lowered and remove the suspension.
Now to install the suspension, use a lock strap to hold the spring in place. This is important because when you install the spring, it prevents it from falling out. And now slip the spring carefully inside the tunnel and bolt the front arm in its place.
Something needs to be used under the front of the old to compress the suspension. There are nylon straps that usually need to be removed and slowly lower the snowmobile. Here comes the role of the limiter strap to be installed now; once that is also done, lower the snowmobile, and now you are good to go heavy steering.
Adjusting the Suspension
To adjust the suspension, place the snowmobile back to its baseline where the suspension is balanced. Now it is ready to be adjusted.
Set the pre-load of the front and center shocks which is the measurement of the difference between the spring’s free length when compared to its installed length.
The next step is to back the spring retainer off until the spring is no longer being compressed and then measure the length of the spring to get the normal length of the spring. Now that we know the standard length of the spring, the spring retainer needs to be compressed to bring the spring to a length of somewhat between 5-10mm. This difference is the pre-load setting.
Limiter Straps & Coupler Blocks
For this step to be completed, the snowmobile needs to be sitting flat on hard, level ground with an even surface with nothing under the skis or track. Now the limiter strap needs to be checked for tension as it should be completely free of any tension. This will make sure that the weight will be distributed in the front and rear suspension. Next, coupler blocks need to be set to the thinnest position facing the rear stop for a neutral setting.
Front Free Sag
The free sag is the amount the suspension compresses under its weight. there is no specific measurement for snowmobiles, but about 20% of the total amount of suspension is what can be assumed for it to be. The front bumper needs to be lifted to the point that the shocks are fully extended and then measure the height of the bumper.
Next, put the snowmobile back on the ground and compress the shocks. This can be done by applying pressure to the front bumper and then release. This needs to be repeated a couple of times to settle the suspension. Now measure the height of the bumper again, and the difference between the two measurements will be the amount of free sag in the front suspension of your sled. This can be done until you reach your desired free sag.
Rear Free Sag
The free sag of the rear suspension needs to be checked by lifting the back off of the ground by the bumper and then set it back down. When it is set back down, the suspension should sag a bit and if it does not, then the shocks do not sag and are at full extension. The amount of pre-load on the center shock can be reduced to give the rear suspension more free sag.
To check the loaded/race sag, more attention needs to be paid. When the suspension has a normal riding load on it the loaded/race sag is the amount of sag the suspension experiences i.e. rider, luggage, and gear. With the normal amount of load on the snowmobile, the coupler blocks should be centered between the stops.
Should You Upgrade Your Suspension?
In today’s fast-changing world, everything upgrades at a blistering speed, why not snowmobile suspensions! Upgrading with every latest model might not be possible for everyone, however, every once in a while an upgrade is what your snowmobile’s suspension needs.
If your suspension has gotten old and you want to get rid of it, you can simply upgrade it with a new one. The upgrades improve the overall functioning of the sled with better steering and anti-bottoming resistance. It helps to better track in the rough terrains and facilitates a plush ride. It does not matter which brand or type of your snowmobile is, be it Ski-Doo, Polaris or Arctic Cat, etc., if the suspension is not upgraded, you will miss out on a great ride.
How Does Suspension React While Snowmobiling?
As already mentioned above, the correct suspension is the deal breaker of a snowmobiling ride. The stock suspension on most snowmobiles is usually soft. This kind of suspension creates an unsettled feeling in the snowmobile. The snowmobile reacts in an unstable way if you drive at high speed and is unpredictable while shifting from changing snow densities.
When it encounters any unforeseen obstacle or firm snow layers, a rider most definitely “hits or slaps” the bottom of the suspension. Nothing can feel any worse than this. The suspension reacts to such slapping and takes on it first before you feel it in your entire machine and body. If the rebound is not at a normal speed and is too slow, your shock will not recover completely before the next hit. This will cause the suspension to “pack up” and operate on the bottom of the stroke, making it uncomfortable for the rider.
Good suspension is a must-have for any enthusiastic snowmobile rider. It is a real game-changer. It makes your ride super smooth and easy and keeps you comfortable as it absorbs most of the shocks without letting them hit you by lessening the impact.