How to set Sag

What is sag and why is it important?

Suspension sag is a fundamental part of suspension setup as it is the first and arguably most important step to make your bike dialed! Static Sag is the amount of suspension travel that is used while you are stationary on your bike. The suspension sag value is measured in percentage of the total travel of the bike with the rider wearing their full riding gear in a neutral riding position.

Sag is very important as it is a universal metric that will allow you to get a good base setup on your bike, get your bike as balanced as possible and be able to have a consistent setup across multiple bikes by transferring the sag metric over.

What is needed to set up sag?

Shock pump (in adjusting an air shock)
A friend? Haha
A measurement device such as a ruler or vernier caliper
Potentially a calculator (if your math is as bad as mine)
Tools to adjust compression and rebound

Step 1: Get ready!

Prep your tools and find a place to lean your bike against.

Step 2: Know or find out your shocks/forks stroke length

You can go about finding two different ways.

The quickest way is to simply measure it. A trick to do this is by bottoming out your shock/fork and using your sag ring. After the shock/fork is fully bottomed out, return it to the fully extended position. Now simply measure the distance from your sag ring to the shock/forks dust wiper
The second option is by looking up your bike info on the manufacturers website. If you find your bike’s shock size, written as A x B, your bike’s stroke will be the second number or smaller of the two. (EX: 230 x 60. 230 will be your eye / overall length and 60 will be your shock’s stroke length.)

Step 3: Determine what Sag you would like to run.

Check on your bike manufacturers website for the suggested sag to run on your specific frame. Ex. : Pivot recommends a specific sag to work well with their suspension system.
Sag is usually different depending on your riding style. Cross-country sag usually varies between 20-25%. Enduro/Trail Sag is usually around 25-30%. DH sag is usually around 28-33%.
Sag is also a personal preference, so if your friend rides 16% sag it might not mean that it’ll be the right setup for you ;)

Step 4: Calculate what stroke length your sag percentage equals to.

Now is the time to do a bit of math and determine what strong length your desired sag equals to. To do so, you need to multiply your shocks total stroke by the desired sag percentage. (Ex: 28% of 45mm = 45 x 0.28(28%)= 12.6mm) In this case, 28% sag on a 45mm stroke shock would give you 12.6mm from wiper to sag O-ring.

Step 5: Set Base air pressure.

The best way to set a base air pressure is going with the manufacturer recommended pressure for your weight bracket. They usually make mention of it in the owner's manual of your bike and/or on their website.
Another way to set a base pressure is by adding your body weight worth of air in your shock and half your body weight in your fork.

*Doing so will give a good base line so you're not too far from your desired sag and wasting time!

Step 6: Mount bike

Mount bike with typical riding gear (Shoes, helmet, protection, water, tools) and ask a friend to hold you steady by sitting on the front wheels and holding your bars or by gently leaning against a wall with your grip/Elbow.

Step 7: Assume your neutral riding position.

Centered over the bike with arms and knees slightly bent.
Key point here is not necessarily how you are positioned on the bike but that you stay consistent with your position every time you use sag as a reference point for tuning.

Step 8: Bounce!

Bounce on the bike a few times to activate the suspension and overcome any stiction that might affect your outcome as well as to confirm your positive and negative chambers are equalized fully.

Step 9: Stand still

Stop bouncing and have your friend bring the sag ring against the dust wiper on your shock/fork while remaining in the neutral position. If you are alone, bring the sag ring against the wiper yourself while staying as stable as possible.

Step 10: Dismount

Gently dismount your bike, trying to avoid compressing your shocks any further.

Step 11: Measure

Now with the shock fully extended again measure the amount of shock stroke used by measuring the distance from the sag ring to the dust wiper (just like when measuring the shocks overall stroke length)

Step 12: Compare this measurement to your desired stroke travel distance.

If you have too much sag, you’ll want to adjust your air pressure higher to stiffen up your suspension. If you're getting too little sag, you’ll want to lower your air pressure to make your suspension softer and achieve your sag Goal.

*If you do not have a zero loss shock pump connector then this process will give you an opportunity to develop a rough estimate on how much pressure you lose each time you remove your shock pump from your shock.

You can do this by noting the PSI number on your shock pump before removing and then again after re-attaching to adjust pressure. It’s not unusual to see a 5-10 psi difference.

Step 13: Repeat!

Repeat this process until desired stroke travel or sag % is achieved. Adjusting in 5-10 psi increments is a great place to start if you’re new to adjusting your suspension pressures.

Step 14: Now it’s time to readjust your compression and rebound settings.

Here is a detailed video on how to do just that

Step 15: Time to ride!

For the first few rides pay attention to any new sensations, positive or negative, that you might experience. This will aid you if you decide to tune your suspension further.