Similar to the size every wheel profile also comes with advantages and disadvantages when compared to each other.
Flat profile: Just as the name suggests, these wheels come with an almost flat/straight profile. Their shape has been designed to offer a wide and stable platform to roll on and they find use in anti-rocker setups quite often.
Round profile: Again, the name gives the shape away. These wheels come with a rounded profile making it easier to control the edges and maneuver the skates. They still offer a fairly wide base and stability.
Balanced profile: You’ll guess where this is going by here. Mainly used on wheels from 80mm where speed and control on and over edges gain relevance. Balanced between biggest possible footprint while on edges and wide enough platform for the straight-line roll.
Bullet profile: With this one, you’ll have to read between the lines a bit to read it from the name already. More pointy, rounded shape to offer the best edge to edge feeling and agility. Mainly used on bigger wheels targeting higher speeds with lots of force on the wheels while taking a corner.