Sprung Mass
Sprung mass is the portion of vehicle mass supported by the suspension springs.
What it includes
The body, battery enclosure, passengers, cargo, and much of the powertrain are normally part of the sprung mass. Some components span the body and wheel sides of the suspension, so dynamic models allocate effective portions rather than placing every gram wholly in one category.
Sprung mass works with wheel rate and damping to shape body heave, pitch, roll, and ride frequencies. Adding passengers or cargo increases supported load, changes static deflection, and may change available bump travel. Self-leveling suspension can restore ride height without removing the extra mass or inertia.
The term is paired with unsprung mass, but the ratio between them is only one factor in ride and handling. Tires, geometry, stiffness distribution, damping, body structure, and control systems also matter.
For body and wheel dynamics, see Suspension Kinematics and Vehicle Dynamics. For how springs support the load, see Suspension Springs.