All skateboard trucks come with their own bushings set up in the package. Sometimes these bushings may not be for you. Maybe the trucks you purchased come with hard bushings, that need time to break in, while you prefer soft bushings. It's a lot of difference between the two. There's nothing wrong with changing them, even on a new pair of trucks. Other times, from excessive grinds, impact and abuse (trucks can last many years) your bushings just break and need a change. Last but not least, pay attention not to overdo it with bolting the kingpin nut, because if the bushings are soft, you can only do that much by screwing. At Stay_K skate shop, you can find three different hardness from Rellik Skateboards and Film Trucks, as well as pivot bushings and bases for replacement. Film Trucks' bushings include the latter in their normal package.