An explanation of compression can be found in the glossary.
To start with, for a front or rear shock, set compression fully off.
If you are finding the bike uses all its travel upon braking, flowing bumps or on the landings from smooth jumps you need to increase the low speed compression, remember a little at a time, just a click and then see how it performs.
For square edged bumps and objects that would require the wheel to move quickly upwards to negotiate smoothly, without using all the travel up and/or bottoming out, then increase the high speed compression
Remember it’s the shape of the obstacle you’re going over
that defines what type of compression it is not necessarily the speed you're going!
Compression problem solver
Symptoms: Not using full travel, feels harsh, poor traction while making turns
Causes: Overly stiff spring or compression damping
Solutions: Lower air pressure or softer coil springs; reduce compression damping
Symptoms: Bottoms out, soft throughout travel
Causes: Spring rate too low throughout travel or too little compression damping
Solutions: More air pressure or stiffer coils springs; increase compression damping
Symptoms: Harsh over large bumps, but good over small ones
Causes: Compression damping too high
Solutions: Reduce compression damping
Symptoms: Excessive sag, feels soft initially but does not bottom out
Causes: Initial spring rate or preload too low
Solutions: Increase air pressure or