In skateboarding, grinds are tricks that involve the skateboarder sliding along a surface, making contact with the trucks of the skateboard). Grinds can be performed on any object narrow enough to fit, such as rails, ledges, and curbs. The trucks of the skateboard are composed of a hard metal without lubricant or bearings on the grinding surface, so they literally grind on the objects they slide across). Grinding can strip paint off of steel and wear down the edges of concrete, stone, aluminum, and wood building materials). Some common types of grinds include:
- 50-50 grind: Both trucks are on the edge of the object).
- 5-0 grind: Only the back truck is on the edge of the object).
- Boardslide: The skateboarder slides along the object with the board perpendicular to it.
- Lipslide: Similar to a boardslide, but the skateboarder slides along the object with the board parallel to it.
Rails are a common object that skateboarders grind on.
