From the J2X all Allards with diameter tubes, and there were parallel side members stitched together by plating. The de Dion rear axle, which was standard on this frame, was located by a Panhard rod. On the J2X there were Alfin drum brakes and the engine was shifted 7in forward, which gave better balance and improved cockpit space. The cycle winged body was similar to the J2 (although a few had enveloping bodywork) and the J2X had wire wheels while most J2s had pressed steel wheels. Like the J2, most went to America where they were extremely successful in SCCA racing, but by 1954 had been overtaken by Ferraris, Jaguar C Types, and the like.