anita, what i meant with "duplicate with transform": model a slice of the wheel at whatever precision you like, then duplicate with transform. first time to line up the rotation, and then just repeat it (with pressing "D" in default setting) many times. after that select all the pieces, combine, merge vertices. done. one piece geometry. if you dont like history, just delete the history afterwards. it might not be effective? well, that might be true if the only thing you did was extrude face. but add more complex modelling, and i am sure you dont want to do it for each nipple seperately. then the duplicate with transform or possibly a animation snapshot abused for modeling might pay off. complicated to use or understand at first, but fast, very powerfull and efficient once you opened your mind.
and never forget: there is always at least 2 ways to do things in maya, usually even more