Rack and Pinion Gears is same of one range of Spur Gears. Rack has a straight bar which is designed as straight and crosswise teeth. Generally, The Rack is as same as Spur Gear that is rolling flat. Pinion Gears are the Normal Gear. If Rack and Pinion Gears both joined together, It is the best example of Spur Gearing. When we rotate a Pinion Gear, it rolling in linear on the Rack.