Know How To Set Your Suspension Sag

Tip #245 from the pages of The Total Motorcycling Manual

suspension sag

A motorcycle’s suspension works in two directions. When you hit a bump, the suspension compresses (the wheel moves closer to the chassis), and then rebounds (the wheel springs back, farther away). Your suspension needs to be set to work properly in both directions with the amount of weight your bike is carrying; setting your bike’s sag is the first step in getting it right.

Sag is how much your machine settles on its suspension at rest. To measure the sag, have a helper lift the rear of the bike as high as possible—if you have a centerstand, just use that to lift the rear wheel off the ground. Now measure from the rear axle to a reference point straight above—the seat, fender, etc. Do the same with the front suspension. This measurement is the suspension value with zero sag—for our example, let’s say the number was about ten inches (250mm). This measurement is called unloaded or free sag.

Now, let the bike stand normally on both wheels, with no rider. Push down on both the handlebar and the seat a couple of times, and let the bike return to normal. Have your helper hold the bike upright, and repeat the measurements you’ve taken; you’ll see that the weight of the bike has settled and compressed the suspension. The difference between this number and zero sag value is called static sag.

Finally, sit on the bike in your riding gear, 
both feet on the pegs and keeping the bike vertical. Repeat the same measurements, and you’ll see the bike has settled even lower. This measurement is 
the ride height.