The Park Tool WAG4 Wheel Dishing Gauge. For a wheel to perform properly, it is important for the rim to be centred between the locknuts of the hub, or dished . To check this, and to make precision adjustments, a wheel alignment gauge (also called a dishing tool ) is a must.The WAG4 allows easy checking of the dish on road, mountain, or BMX wheels from 16 to 29 . It works with any hub width and its innovative design even allows it to be accurately used with the tire still on the wheel. An accurate and truly versatile wheel alignment gauge that belongs along side every truing stand.