Roller

The Roller tires are a set of default tires in Mario Kart 7. They're the smallest wheels in the game, and they offer the best acceleration and handling boosts among all the kart parts. However, they also offer the lowest speed and weight boosts.

The Roller tires reappear in Mario Kart 8. Although they are still the smallest tires, they are red with a yellow center, instead of black with a silver center, like in Mario Kart 7. The Roller tires are still available to use right off the bat, but despite this, CPU players will never use them. A variant of the Roller tires, called the Azure Roller tires, also appear in Mario Kart 8.

Stat boosts
Stat values are out of 6.

Mario Kart 7

 * Speed: -0.75
 * Acceleration: +0.75
 * Weight: -1
 * Handling: +2
 * Off-Road: -1.25

Mario Kart 8

 * Speed: -0.5
 * Acceleration: +1
 * Weight: -0.5
 * Handling: +0.25
 * Traction: -0.25