What is sag, and how do I set it?

By Travis Flateau, TBT Racing · tuning since 1992

Sag is how far your bike sinks under its own weight and under you. Set it right and the bike turns, tracks and lands the way it was built to.

Two kinds of sag

  • Static sag: how far the rear sinks with just the bike on the ground. On most full-size dirt bikes it's around 30–40mm.
  • Race sag (rider sag): how far it sinks with you on it in your gear. On most full-size dirt bikes it's around 100–110mm.

How to check it

  • Lift the rear wheel off the ground and measure from the axle to a mark on the fender.
  • Set the bike down, sit on it in riding position, and measure again. The difference is your race sag.
  • Turn the shock preload ring to change it.

The TBT tip

If you can't get race sag and static sag both in range, the spring is wrong for your weight. That's a spring problem, not a preload problem.

Get a TBT setup for your weight