Measurements of the shear viscosity and the first and second normal stress coefficients are shown at 175 degreesC for a nearly monodisperse polystyrene melt with Mw = 200 kg/mol (PS 200 k). Tests are performed on a cone-partitioned plate shear rheometer and cover a range of Weissenberg numbers (T(d)gamma) from 0.13 to 40. Experimental problems encountered are the axial compliance of the rheometer and the normal force capacity of the transducer. The later limits the maximum shear rate to T(d)gamma = 40. Experimental data are compared with the models of Ottinger [termed thermodynamically consistent reptation model (TCR), Ottinger, H. C., J. Rheol. 43, 14611493 (1999)] for the convective constraint release parameter (52 = 0, 1, and 2 and Mead, Larson, and Doi [termed Mead, Larson, and Doi (MLD), Mead, D. W., R. G. Larson, and M. Doi, Macromolecules 31, 7895-7914 (1998)] for (delta(2) = 1. The steady state and transient values of P-21, N-2, and NI agree qualitatively well between both models and the experiment. The predicted normal stress ratio -N-2/N-1, is sensitive to the magnitude of delta(2) in the TCR model, similar to the extinction angle. The MLD model yields \N-2\ and Psi values lower than both experiments and the TCR model with 62 = 1. From a comparison with the chain stretch time T-S (0.065 s) it can be shown that the overshoot O of \N-2\ and p(21) are linked to chain orientation, whereas O(N-1) is associated with chain stretching. The magnitude of the overshoot for all shear rates increases as O(NI) < O(N-2) < O(eta) for PS 200 k. In comparison, a polydisperse polystyrene melt shows stronger shear thinning of -N-2/N-1 and an increase of the magnitude of the overshoot as O(N-1) < O(eta) < O(N-2). (C) 2004 The Society of Rheology.