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: went over a speed bump now have a scraping/grinding noise under the bed when driving

It sounds like one of your leaf spring shackles has broken. It is very common for them to get rusty and break. The noise you are hearing is probably the shackle running on the underside of the bed. Go...

Q: Clunking noise from front of car when driving slowly or turning slowly

Hi there. Most clunking sounds, especially while turning, are attributed to worn out bearings or bushings - especially CV joints, tie rod ends, and also stabilizer bar joints. Not sure why it would only happen while it is hot outside,...

Q: Can I replace suspension springs to soften ride?

Hi, thanks for writing in. You may want to check into the different Sena-Trac rear shocks for the vehicle. The shocks may soften the ride. These vehicles are known for a harsh ride and these shocks may help. If you...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...