Unsprung Mass
Unsprung mass is all of the mass on the vehicle that is not supported by the suspension. This includes: the tire, the wheel, the hub, the upright/knuckle assembly, as well as a portion of the spring assembly, control arms, CV axle, and toe rods.
To Calculate[edit | edit source]
Add the mass of each upright with all of the hardware on it (outer tie rod ends, brakes, the wheel, etc) to the mass of half of all suspension connecting rods as well as half the mass of the spring and damper system. For example, on the F25 to calculate unsprung mass the following would be summed:
- half the weight of each control arm
- half the weight of each rear toe rod
- half the weight of each CV axle
- half the weight of each tie rod
- the weight of the bar beneath the spring and damper
- half the weight of each spring and damper
- the weight of each upright with the wheel, brakes, and all supporting hardware (bolts, nuts, washers)
Alternatively, unsprung mass can be calculated by deducting the sprung mass from the total vehicle mass, although this is usually more difficult due to the issues of finding the mass of the chassis without the suspension to support it.
