Roller

The Roller tires are a set of default tires in Mario Kart 7, Mario Kart 8, and Mario Kart 8 Deluxe.

Mario Kart 7
The Roller tires are the smallest tires 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. Despite those flaws the Roller tires strongly excel while underwater however, and their air stats are given a positive boost as well. They are also fairly stable compared to most other tires.

Mario Kart 8 / Mario Kart 8 Deluxe
The Roller tires reappear in Mario Kart 8 and Mario Kart 8 Deluxe. 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.

Much like in Mario Kart 7, the Roller tires offer the highest acceleration boost of all tires, but their handling boost is much less extreme than before. Fortunately, they don't hinder speed and weight as heavily as in Mario Kart 7, despite still being the slowest and lightest tires in the game. In terms of their hidden stats, the Roller tires have the highest stat total of all the tires in the game.

A variant of the Roller tires called the Azure Roller tires also appear in Mario Kart 8 and Mario Kart 8 Deluxe, where they share the same stats as the Roller tires. The Button and Leaf Tires also share the Roller tires' stats, despite having a different appearance.

In Mario Kart 8 Deluxe, the Roller tires have received slightly different stats which they now exclusively share with the Azure Roller tires. They no longer boost air speed, and their acceleration and Mini-Turbo stats are slightly lower as well. The only two CPU-controlled characters who uses these tires are Ludwig and Baby Luigi. Ludwig uses these tires alongside the Biddybuggy, while Baby Luigi uses them alongside the Mr. Scooty.

Mario Kart Tour
Roller tires return in Mario Kart Tour on several karts, such as the Birthday Girl, Birthday Girl Rosalina, Bullet Blaster, Bulls-Eye Banzai, and Ribbon Rider. On the first four karts on the list, they resemble a mixture of their Mario Kart 7 appearance (black tire treads) and Mario Kart 8 appearance (yellow center). On the Ribbon Rider, they have their Mario Kart 8 appearance.

Stat boosts
Stat values are out of 6.

Mario Kart 7

 * Speed: -0.75
 * Sea Speed: +1
 * Air Speed: +1
 * Acceleration: +0.75
 * Weight: -1
 * Handling: +2
 * Sea Handling: +1.25
 * Air Handling: +1
 * Off-Road: -1.25
 * Mini-Turbo: +1
 * Stability: +1
 * Drift: -1

Mario Kart 8

 * Ground Speed: -0.5
 * Water Speed: 0
 * Air Speed: +0.5
 * Anti-Gravity Speed: -0.5
 * Acceleration: +1
 * Weight: -0.5
 * Ground Handling: +0.25
 * Water Handling: +0.25
 * Air Handling: +0.25
 * Anti-Gravity Handling: +0.25
 * Traction: -0.25
 * Mini-Turbo: +1

Mario Kart 8 Deluxe

 * Ground Speed: -0.5
 * Water Speed: 0
 * Air Speed: 0
 * Anti-Gravity Speed: -0.5
 * Acceleration: +0.5
 * Weight: -0.5
 * Ground Handling: +0.25
 * Water Handling: +0.25
 * Air Handling: +0.25
 * Anti-Gravity Handling: +0.25
 * Traction: -0.25
 * Mini-Turbo: +0.75

Names in other languages
Klein Piccoli