Building a wheelset is a rite of passage for most bike mechanics. Making sure the rim is dished properly over the hub's locknuts is an essential part of the wheelbuild, and for the wheels to fit in the frame and fork and handle properly. Park Tool's Wheel Alignment Gauge - WAG-4 makes it quick and easy to see if wheels are dished correctly and the sliding blocks allow it to measure any type of bicycle wheel between 16 and 29-inches. And unlike other designs, the WAG-4 allows you to check the dish while the tires are still on the rims and work with any hub spacing. Simply place the blocks on the rim and dial in the gauge's pointer on the hub's locknut. Flip the wheel over and read the distance from the blocks to the rim or the pointer to the locknut to check dish. Adjust the rim over as necessary.