To replace the under-deck mower wheels on a John Deere 445, you first need to make sure that the deck is level. Once this is done, park the John Deere on a concrete level surface. Lower the mower deck to the normal position. Measure from the bottom of the wheel to the ground - this should be anywhere between 1/8 - 1/2 inch. Remove the outside bolt on the wheel pulling it away from the mower deck. Reposition the wheel into one of the mower deck flanges. Here you will see that there are four holes that are used to adjust the wheels. Lastly, place the bolt through the hole that gives the wheel the correct clearance. Repeat this for all wheels that need to be replaced.