ocr: TYPES OF GEARS T - HERE ARE that pass FOUR on basic force typesof and Rack pinion and gear gears motion in machines: rack and pinion gears, worm gears, bevel gears, and spur gears.. .A rack and pinion gear changes circular motion into linear (straight) motion. A worm gear changes the direction of Worm gear motion and greatly alters its speed orf force. A bevel gear also alters the Bevel gear direction of the force and motion.A spur gear changes the direction ofthe motion and Changing gear its speed or force. Gears change the direction ofmotion, Spur gear its. and speed some also orforce change