This study presents the results of experimental tests on single flare (SF) terminations in brake tubes with diameters of ∅4.75 mm and ∅6.35 mm, and wall thickness of 0.9 mm and 1 mm, respectively, using the FALCON toolset. The research aimed at determining the optimal range of initial tube protrusion that results in a flare diameter compliant with the BN-90 3617-09 standard. The paper provides a detailed description of the testing methodology It presents raw measurement data, statistical calculations, and their analysis. Conformity or nonconformity with the specification was assessed according to the guidelines outlined in the PN-EN ISO 14253-1:2018-02 standard. For tubes with the diameter of ∅4.75 mm and the wall thickness of 0.9 mm, the average measured flare diameters for the initial protrusion in the range of 4.4–5.0 mm fall within the tolerance specified by the standard. However, when accounting for measurement uncertainty, the required flare diameters are obtained for the initial protrusion in the range of 4.6–5.0 mm. In the case of tubes with the diameter of ∅6.35 mm and the wall thickness of 1.0 mm, the average measured flare diameters meet the standard requirements for the initial protrusion of 4.6–5.0 mm, whereas, considering the measurement uncertainty, the required flare diameters are obtained for the initial protrusion in the range of 4.8–5.0 mm.