This is an important tool for wheelbuilding. Park's Portable Wheel-Dishing Gauge accurately checks the rim centering (sometimes called dishing) on all 26-, 27-inch and 700C wheels. Measurements are taken comparing one side of the wheel to the other to ensure that the rim is perfectly centered over the hub. Plus, this sweet tool easily collapses and fits into most tool boxes. It's perfect for the race or home mechanic.