My Wheels Get Caught on Small Pebbles

One of the biggest enemies of skateboarders is small pebbles. When a wheel hits a pebble, the board can suddenly slow down or stop. But why does this happen? Normally, when a wheel hits a raised edge on the ground, it initially experiences a force pushing it backward, against its direction of travel. However, as the wheel moves over the edge, that force quickly becomes more vertical, helping lift the wheel upward. A pebble, on the other hand, is not fixed to the ground. As soon as the wheel hits it, the pebble starts moving along with the wheel. As a result, the force the pebble applies to the wheel remains mostly horizontal instead of shifting upward. In other words, because the wheel cannot roll over the pebble, the pebble continues to resist its forward movement, causing the board to stop abruptly. Cleaning the ground or switching to softer wheels may help.