How to tell if compression damping settings are working? This is an embarrassing novice question ... I got a mountain bike with a fork that has low and high speed compression damping settings. This is the first time I am riding a bike with an air fork. I do not have experience with them. I cannot notice any difference in the fork's behaviour when going from minimum to maximum damping or vice versa. In contrast, I can notice a difference in the rebound setting. Is this normal? How can I determine if it is working correctly?
Try taking all the air out so you can feel just the damper’s resistance. Low speed compression will be noticeable when doing body movements such as preloading, weight shifting, or braking. High speed compression is for events such as hitting big drops and large square edge impacts. The easiest way to test that is to smash into a square curb (perhaps with a bit of air to prevent fork damage).
Remember that the “speed” here is shaft speed, not bike speed. Shaft speed is how fast the damper shaft is moving through the oil column. Smashing a curb at walking speed is a high shaft speed event, just as pumping through a compression at 40km/h is a low shaft speed event.