Quick release (QR) skewers are one of the most common ways to hold the wheels on a bicycle. QR skewers operate using a cam to hold the wheel in place, and so need to be closed tightly in order to function properly. There are also two springs, which should be mounted one on either side of the wheel with the narrow end pointing to the hub. To close a quick release, tighten the nut on the side opposite the lever until the skewer becomes snug when half-way closed and takes firm pressure to close all the way. Close the skewer all the way, and you’re set.