A floating locking tremolo is balanced between the pull of the strings and the springs in the back. If you remove all the strings at once, the bridge tips forward and you lose that balance. Changing one string at a time, or wedging a block of wood or a tremolo stopper under the bridge, keeps things stable.
Steps:
- Unlock the nut clamps.
- Set the fine tuners to roughly the middle of their travel.
- Detune one string, loosen its saddle clamp and remove it.
- Prepare the new string. Most double-locking bridges clamp the string end in the saddle, so the ball end is usually cut off. Check your bridge's instructions.
- Clamp the string in the saddle. Snug is enough; overtightening can damage the clamp parts.
- Thread and wind the string at the headstock, then tune it to pitch.
- Repeat for each string, retuning as you go. Each change affects the others.
- Stretch the strings and retune several times.
- Lock the nut once everything holds pitch, then use the fine tuners for small adjustments.
If you change to a different gauge, the tremolo springs will probably need adjusting to bring the bridge back to its resting position. If you're not comfortable doing that, a qualified tech can set it up for you.