There are several tires you can unlock for your kart in in Mario Kart 7 for the Nintendo 3DS, which are unlocked by collecting coins in Grand Prix mode.
All kart tires are unlocked in random order, but here are the tires that are available.
Slick Tires
Slim Tires
Sponge Tires
Check out my other guide if you’re looking for the full list of unlockable kart parts in Mario Kart 7.
