Basic Automotive Tire Service Practice Test 2026 – Complete Exam Prep

In the tire size designation P225/60R16, the diameter is represented as a numerical value in inches. The "16" at the end of the designation signifies the diameter of the wheel or rim that the tire is intended to fit, which is 16 inches. This is a standard way of denoting rim diameter in tire sizes, allowing consumers and technicians to quickly identify the size of wheel that corresponds with the tire.

Other options do not accurately represent the diameter in this context. A percentage of width is indicated by the aspect ratio (the "60" in this case), which conveys the height of the sidewall as a percentage of the width of the tire. A letter designation is used to indicate the type of tire or construction (here, the "R" indicates it's a radial tire), and weight specifications are not relevant when discussing the diameter of a tire. Understanding this numerical representation of diameter is crucial for ensuring the proper fitment of a tire on a vehicle.