An axle cartridge member receives a pair of torsion stub axles at opposite lateral sides thereof. The torsion stub axles include elongated axle housings, which are sandwiched between two parallel plates to align the torsion stub axles with respect to one another. The cartridge member includes a central arch extending between the two torsion stub axles, which can provide additional ground clearance when the axle cartridge member is mounted to a trailer.