An extendible axle member (146 or 148) is provided for a pivoting axle of an agricultural harvester (100), the extendible axle member (146 or 148) having an elongate telescopic portion (400) with bearing surfaces for being slidably received in an outer axle member (142 or 144), wherein the elongate telescopic portion (400) is formed integral with and abuts a C-frame for supporting a steering knuckle (158 or 160).