  The effects of rapid rotation on stellar evolution can be profound. We are
now beginning to gather enough data to allow a realistic comparison between
different physical models. Two key tests for any theory of stellar rotation are
first whether it can match observations of the enrichment of nitrogen, and
potentially other elements, in clusters containing rapid rotators and secondly
whether it can reproduce the observed broadening of the main sequence in the
Hertzsprung-Russel diagram. Models of stellar rotation have been steadily
increasing in number and complexity over the past two decades but the lack of
data makes it difficult to determine whether such additions actually give a
closer reflection of reality. One of the most poorly explored features of
stellar rotation models is the treatment of angular momentum transport within
convective zones. If we treat the core as having uniform specific angular
momentum the angular momentum distribution in the star, for a given surface
rotation, is dramatically different from what it is when we assume the star
rotates as a solid body. The uniform specific angular momentum also generates
strong shears which can drive additional transport of chemical elements close
to the boundary of a convection zone. A comparison of different models and
their reproduction of observable properties with otherwise identical input
physics is essential to properly distinguish between them. We compare detailed
grids of stellar evolution tracks of intermediate and high-mass stars produced
using several models for rotation generated with our new stellar rotation code.
