A suspension trailing arm is used for suspending a vehicle chassis from a beam type axle. The trailing arm comprises a chassis mounting feature, an axle mounting feature, and an arm portion intermediate the chassis mounting feature and an axle mounting feature, characterized in that the arm portion comprises a generally X-section profile having four limbs, two limbs in the four limbs are orientated to provide grooves upward during installation, wherein the shape limits an X-axis horizontally extending through the X-section profile center point, and the two limbs of the four limbs providing the grooves tilt up with respect to the X-axis, and each limb follows a substantial S-shaped path from a chassis lining to a shaft package part. The invention also provides a heavy vehicle suspension assembly including the suspension trailing.