an improved wheel rim , an improved spoke nipple and an improved wheel are disclosed . the rim has spoke openings and a threaded end of each spoke extends therethrough . an internal nipple with a threaded bore is connected to the threaded spoke end so that a first , ball - shaped , rounded end of the nipple is seated on the rim . a portion of the rim around each spoke opening is deformed or removed so as to define a portion of a socket with the same curvature as the first end of the nipple . this minimizes the required diameter of the spoke opening in the rim and maximizes the area of the rim socket surface . the invention also extends to an external nipple with a rounded collar in combination with a rim including a concave rounded rim surface formed in the rim itself .