You'll need to periodically replace the wheels on your inline skates as you notice their performance starts to degrade -- or you can swap wheels out as a quick, easy upgrade to stock skates. Choosing the right wheels depends on your skating style and personal preference.
Two major factors to keep in mind are size and durometer, or hardness. The larger your wheels, the faster you'll go, but smaller wheels are more maneuverable. That's why fitness and general-purpose skates usually have mid-size wheels around 80 mm to 90 mm in diameter; aggressive skates have much smaller wheels in the neighborhood of 52 mm to 60 mm for greater agility, while marathon and racing skates come with wheels that measure between 90 mm and 110 mm.
Durometer measures the hardness of your inline skate wheels; the higher the number, the harder the wheels. As a general rule beginners are usually better off with softer wheels, which provide more grip (78a and 80a are both very common). A durometer of 82a to 85a is good for varied terrain, while aggressive stunt skates may have wheels with a durometer of up to 90a.
Your choice of wheels depends as much on your personal style as on the type of skating you're doing -- but several brands stand out from the crowd in their given genre. For speed skates, Atom Whip wheels (Est. $13.50 to $24 each) are particularly popular. Atom Whip wheels come in 100 mm or 110 mm sizes, with a hardness of up to 89a; a couple of reviewers say that these wheels grip the floor at an indoor rink better than other brands they've tried.
For aggressive skates, 58 mm Valo Brand Team Wheels (Est. $18 for 4) are one of the most popular options. Reviewers say they look great but, more importantly, are smooth, solid and durable. The 59 mm M1 Dual Duro wheels (Est. $35 for 4) also draw high praise for their durability: These are the "longest-lasting wheels I've ever had," writes one reviewer at RollerWarehouse.com.
If you use anti-rocker wheels (smaller wheels that sit in the middle positions on the skate -- they don't touch the ground, but instead help lock you in for tricks like grinds and slides), one of the most popular brands is Moonshine's UHMW (Est. $18 for 4). "After 10 hours of combined street/park skating these wheels look almost brand new. Ledges/rails/coping, everything slides better [than] before," writes one reviewer at AggressiveMall.com.
And finally, for hockey players, Labeda produces a couple of very popular wheels. Reviewers say the 78a Labeda Shooters (Est. $5 each) are durable, grippy and fast when playing outdoors. And the Labeda Asphalt Hard 80A (Est. $6 each) is perfect for prolonged play outdoors; reviewers say they're grippy too, and will last for as much as a year of heavy play on relatively rough rinks.