Howard (1993) finds a relationship between the tilt angles of BMRs (Bipolar Magnetic Regions) and the separation between their leading and following polarities; the tilt angle increases with polarity separation. Here we present a more detailed analysis of this relationship and show that this effect constrains the strength of the magnetic field at the bottom of the convection zone to a value between 40 and 150 kG, which confirms the constraints put by D'Silva and Choudhuri (1993) based on Joy's law (the tilt-latitude relationship), through an entirely different approach.