A wellhead housing has a bore with a support shoulder, a ramp surface extending upward and outward from the support shoulder, and a recess extending upward from the ramp. A split, resilient load ring is carried in an initial position in the recess. A retractable and axially movable latch ring is carried in the recess above the load ring. A casing hanger has a profile that engages the latch ring as the casing hanger moves downwardly in the bore, causing the latch ring to move downward and pushing the load ring to the set position.