An air-ride beam-type axle/suspension system for a heavy-duty vehicle with a gross axle weight rating of greater than 23,000 lbs./axle includes a pair of transversely spaced beams. Each one of the beams includes inboard and outboard sidewalls. A large diameter axle extends between and is rigidly connected to the beams via a pair of axle-to-beam connections. Each one of the axle-to-beam connections includes a sleeve having an increased thickness rigidly connected to the axle and the beam. Each sleeve is formed with at least a front and a rear window located between the beam sidewalls. The inboard and/or outboard edges of the sleeve windows are spaced relatively far from the beam sidewalls. The sleeve windows are asymmetrically angled with respect to the horizontal centerline of the axle at design ride height. The axle/suspension system reduces weight while maintaining desired stiffness and durability of the axle/suspension system.