m. (of a
wheel rim)
having a sunken
channel going all the way around the inside center of the rim. A rim is the circular metal structure around which a tire is fitted, as on a car. When removing a tire from the rim, the sunken
channel provides a
space into which one side of the tire can be pushed, thus making it easier to
force the opposite side of the tire over and off the rim. Without a
drop center, it is more difficult to manipulate the tire and get it off the rim.