A catheter has a distal assembly with at least one loop with ring electrodes. A single continuous puller wire for bidirectional deflection is pre-bent into two long portions and a U-shape bend therebetween. The U-shape bend is anchored at a distal end of a deflectable section which is reinforced by at least one washer having at least two holes, each hole axially aligned with a respective lumen in the deflectable section. Each hole is centered with a lumen so that each puller wire portion therethrough is straight and subjected to tensile force only. A proximal end of the support member is flattened and serrated to provide a better bonding to the distal end of the deflectable section.