Disregarding shear effects is a principal defect in predicting the bending strengths of small clear specimens of timber according to standards. The present study proposes a method to determine spans of 2 x 2 cm wood specimens of black locust and chestnut for shear free deformations in static bending. It was found that for both ring-porous species, spans of at least 40 cm in a bending test would ensure a negligible influence of shear on modulus of elasticity.