Cyclic queue models have been used in the past to determine fleet size and evaluate fleet performance. Analytic solutions can only be obtained for exponential service times or exponential service times plus a generalized transition time. We have carried out several hundred simulations of cyclic queues with non-exponential service times and have developed a technique for estimating the effect of non-exponential distributions using the analytic results as a basis. Most of the work presented here deals with single-lobe systems. We also present some results for multi-lobed cyclic queues which introduce new problems of analysis and evaluation.