Setting sag is the first (and arguably most important) step to dialing in the suspension on your snowmobile. Sag is static ride height. That is, the amount your shocks compress when you’re in your regular riding position. The goal of this video and article is to dive deeper into how it can impact your riding comfort and control.
What is my regular riding position?
If you tend to stay seated while riding mild trails, you should measure sag when you’re sitting down.
Conversely, if you’re a more aggressive mountain rider, you should be standing in the neutral attack position while measuring sag.
What does sag do?
Sag puts you and your sled in the ideal starting riding position to engage the terrain in front of you. It is the resting point that you and your sled will continually return to for the duration of the ride.
Being at the proper sag point for your style of riding will help you feel more comfortable and controlled. It helps the sled compress and rebound through front and rear travel in a balanced way and keeps your shock in what we call the “Ride Zone.”
What’s the Ride Zone?
The Ride Zone is where the shocks on your sled should spend most of their time during your ride in order to maximize performance and comfort.
To figure out where the Ride Zone is, we started by looking at years-worth of field-testing data collected to help determine what optimal performance and comfort would be in this range without sacrificing bottom out support and top end comfort.
In order for your sled’s shocks to spend time in this optimized Ride Zone, you need to have sag set up properly on your snowmobile.
How much sag do you recommend?
We recommend starting around 30 percent. This is a great all-around setting for trail riding and still allows most riders to have bottom out support and a tight-feeling sled when they increase compression damping as they enter the powder.
If you’re primarily a mountain rider who spends most time in powder, you might want less than 30 percent sag to make it easier to initiate turns, float over the powder, and maximize bottom out support.
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This video is about coil shocks, but I have air shocks. What do I do?
Follow the same steps in the video to find the necessary measurements so you can know the measurement of where your sag should be. Once you’re ready to adjust, here are a few tips:
- Use a shock pump to adjust to adjust both front ski shocks and the rear track shock;
- The EVOL chamber should always be at a higher pressure than the main chamber;
- Be sure to set your sag in an environment similar to where you will be riding. Don’t set sag in your 60-degree garage and expect the air pressure (and sag setting) to be the same when you’re in -20 degrees at 5,000 feet elevation.
If you have more questions about setting up your sled’s air shocks, hang tight. We will be covering this in future videos.
My sled uses a rear track shock with a coil spring, not a torsion spring. How do I adjust preload on that?
Follow the same steps in the video to find the necessary measurements so you can know the measurement of where your sag should be.
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Once you’re ready to adjust, adjust preload on your rear track coil shock in the same way you would adjust the preload on one of your front ski shocks.
What tools will I need?
- Owner’s manual
- Tape measure
- Marker
- Notepad
- Pen
- 4mm Allen key
- Torsion block tool (Ski-doo only)
- Ratchet strap
- Floor jack
- Shock pump (air only)
- FOX spanner wrench (803-00-766), only if you want help preloading the coil springs
What is the formula to help find sag for the front ski shocks?
Sag % = change in back end travel (X - Y) divided by the stroke of the shock (Z). Sag % = (X - Y) / Z.
X = Uncompressed length; Y = Shock length at sag; Z = Stroke length.
What is the formula to help find sag for the rear track shock?
Remember, the rear travel of your sled is not limited by the shocks, it is limited by the sled’s suspension system. So rather than measuring shocks, we will be measuring sled travel.
First, you need to find the total travel of the sled. Total travel of sled = uncompressed length - bottom out length:
Sag % = change in overall sled travel (X - Y) divided by the travel of the sled (Z). Sag % = (X - Y) / Z.
X = Uncompressed length; Y = Sag length from floor; Z = Total travel of sled.
If you want to learn more about compression and rebound adjustments, and the specifics of “how a shock works,” we’ll be releasing videos and posts on these topics soon. In the meantime, visit this updated Snow landing page to see our new lightweight mountain shocks:
Like what you see? Check out all the FOX Academy videos for powered vehicles and mountain bikes here.
Want to learn from the pros? Check out the FOX Backcountry team.
