An improved skateboard or roller-skate truck is disclosed containing a novel yoke, base, grommet, wheel and bearing combination which delivers high precision steering, advanced steering control and more precise wheel alignment. The truck comprises a base plate and a yoke having a body portion with an aperture through it. There is a bearing member in the yoke next to the aperture. A post is mounted in the base plate and extends through the aperture in the yoke. A novel resilient grommet with a bearing surface on its face is mounted on the post and engages the bearing member in the yoke to restrict arcuate movements of the yoke. A novel wheel bearing is also disclosed which incorporates paired ball bearing casings with bell-shaped members on the outside of each casing slideably meeting each other inside a skate wheel where the bells self adjust the bearings to accommodate imperfections in the bearing seat levelness, bearing seat spacing, axle diameter and axle straightness.