Tire

Tires (also known as Wheels or written as Tyres in British English versions) are vehicle parts that appears in all the Mario Kart installments, but are only customizable in Mario Kart 7, Mario Kart 8 and Mario Kart 8 Deluxe. Tires alter the speed, acceleration, and weight stats. The tires have changed constantly throughout the two games, varying in size and features.

Mario Kart 7
The tire customization first appears in Mario Kart 7. Each tire affects the speed and weight of the vehicle.

Mario Kart 8 / Mario Kart 8 Deluxe
Tire customization returns in Mario Kart 8 and Mario Kart 8 Deluxe. The stats have not changed much from the previous game, but in anti-gravity the speed and handling are affected. In addition to the new tires, every customizable tire from Mario Kart 7 excluding Mushroom and Red Monster reappears in this game.