The ratchet set is an alternative version of the spanner set. Although the ratchet set is much faster to use when tightening bolts, it cannot be used to tighten nuts that are attached to rods/pipes (e.g. the brake/clutch/fuel line nuts and the steering rod adjusters), so it cannot completely replace the open-ended spanner set.
With a standard spanner, it is necessary to repeatedly remove it from the nut and reattach it in a different orientation in order to continue tightening it. This is simulated in-game by the use of the mouse wheel, which the player naturally has to perform a similar action on with his finger.
By contrast, the speed advantage of the ratchet is obtained by quickly moving it back and forth, relying on the ratchet mechanism to keep the nut turning in the correct direction. The player obtains the same advantage with the mouse wheel, if he moves it back and forth rapidly without removing his finger.
The ratchet set can be opened by pressing F while looking at it. Sockets can be swapped by first pressing 2 to enter tool mode, and then pressing LMB on the desired socket inside the opened ratchet set. Pressing F while holding the ratchet changes the direction of torque.
Tools cannot be placed back inside the ratchet set, they can only be swapped. This does not affect gameplay in any way, simply press 1 to go back to normal hand mode when the held tool is not needed anymore.
The set includes a spark plug socket, but notably lacks a ruler, which must still be used from the standard spanner set to check tire wear. The screwdriver included in the ratchet set is identical in function to the standard one, and does not have a ratchet mechanism.