Abstract The present study deals with the effect of the variation of the contact point between the support and load application rollers in three-point and four-point bending tests and the possible influence of horizontal reactions, under the assumption of small bending angles. Therefore, this study includes some factors that were not taken into account when the effect of horizontal displacements that generate span variation was investigated by the first author. The analytic approaches corresponding to three-point and four-point bending have been compared with experimental results that correspond to a unidirectional carbon/epoxy specimen. The flexural modulus obtained with the new approach in all experimental conditions is near constant. Moreover, the calculated load-displacement curves obtained with that modulus matches the experimental curves.