Which castors should I choose for my chair?

As a general rule, carpet castors work better on soft flooring like carpets which offer more friction.

Hard floor castors have a slight braking system so there is more resistance on solid flooring to avoid chairs rolling too far or too fast.

It's best to select the castors for the floor surface you will mostly be using the chair on. Hard floor castors can be used on carpets but the chair may not move very easily and carpet castors can be used on hard floors but the chair will be more difficult to keep still.