1/2" at the thickest side and 3/16" at the thinnest side. Hard riser pads are use to adjust the distance of the trucks base plate to the deck. The most common reason for doing this is to avoid wheel-bite, where the wheels would rub against the deck while making turns. If you will be using wheels over 70mm in diameter or shorter trucks like Tracker, you may need to use a riser. If you have questions about your specific setup, please contact us.