Skip the auto shop - Our mechanics make house calls

Q: What Are Sprung And Unsprung Weight And Why Do They Matter?

asked by on

What are sprung and unsprung weight and why do they matter?

A: First, we will discuss unsprung weight. Uns...

First, we will discuss unsprung weight. Unsprung weight, when considering the automobile, is the mass of the vehicle's suspension system. To make this clear, the unsprung weight has to do with the vehicle's suspension system, the part of the vehicle that supports the chassis and drives the wheels into contact with the ground. Unsprung weight usually includes the wheels and anything directly connected to them. You may consider a portion of the struts, braking system, axles, wheel bearings, and vehicle control arm assemblies when speaking of unsprung weight.

The mass of these items is not supported by the suspension system and is the unsprung portion of the vehicle's total mass. When observing a vehicle traveling over a bump, the vehicle's chassis seems to rock while the wheels and tires remain in contact with the road. The portion of the vehicle that does not rock is unsprung mass, while the moving chassis represents the sprung mass of the vehicle.

Sprung mass represents the portion of the vehicle’s weight that is supported by the suspension system. The sprung mass includes the vehicle’s chassis and anything directly fastened to it that is able to move while the unsprung mass does not. You may consider the seats inside the vehicle, the engine and transmission assembly, and a portion of the drivetrain as sprung weight.

Unsprung and sprung mass are very important when considering ride comfort and vehicle traction control.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Car door not shutting

Hello. It sounds like your door stay has come apart, and is not allowing the door to close. The only repair is to replace the door hinge that has the door stay built into it. Servicing a door that will...

Q: What is left upper strut bushing support

If you are referring to the strut mount or mount bushing, the job can be done but should be tackled by an experienced technician as the wrong move can cause serious injury or damage to personal property. The suspension strut...

Q: Rear suspension

Hello. You cannot use these springs on your car. You may need to talk to the company that sells the mobility lift to see if they have a solution for you since it is very common to have these lifts...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.