Loading

Unsprung weight

 

Unsprung weight

"Sprung" weight is a term used to describe the parts of a car that are supported by the front and rear springs. They suspend the vehicle's frame, body, engine, driver, all liquids and the power train above the wheels. These are quite heavy assemblies.

The "unsprung" weight includes wheels and tires, brake assemblies, the rear axle assembly, and other structural members not supported by the springs. We can say all parts outboard from suspension springs.

"Unsprung weight" is an important concept. This is weight that is not supported by the suspension of the car. This usually includes a some percentage of the weight of the suspension itself, including control arms, push-road, and struts. In fact in the case of a Formula One car, we should say 'semi-sprung' rather than 'unsprung' because each tire acts as a spring in its own.

The Lotus 72 was still winning races five years after its launch. Today is hard to imagine a time when one of the Formula 1 biggest teams would run the same chassis for six seasons. Between 1970 and 1975 Lotus did just that, winning 20 races, two drivers' titles and three constructors' championships. In all there were six specifications of the Lotus 72, but the fundamental design remained unchanged throughout. It is one of the most iconic Formula One cars of all time and its success and longevity in the sport are testament to its brilliant design. Some of the concepts behind the Colin Chapman- and Maurice Philippe-designed car were at least two years ahead of their time. Its side-mounted radiators and overhead airbox provided engineering solutions that are still in use on modern F1 cars and its in-board brakes were just one example of Lotus's briliant idea how to reduce unsprung weight.

Reducing unsprung weight is the key to improving handling. The lower the unsprung weight, the less work the shocks and springs have to do to keep the tires in contact with the road over bumpy surfaces. Lot of problems, if not all of them is caused by inertia. Bigger weight means higher inertia. Higher inertia means more workload for shocks and springs to keep tiers on the ground. If unsprung components have a high mass they are harder to accelerate/decelerate and thus it is more difficult for the suspension to maintain a consistent tire load.
An easy way to reduce unsprung weight and improve traction in normal cars is to replace stock wheels and tires with special magnesium lightweight wheels. Note that as the wheel diameter or width increases, the weight of the overall wheel and tire package increases, thereby increasing unsprung weight.
F1 and racing cars fight high unsprung weigh with sophisticated and expensive light materials and hours and hours of engineers work.

 

Back to the top of the page

 


Books to read


Some useful links:

Technical
- f1technical.net, a great site with a lot of technical information’s and explanations. Site is updated daily with news from F1 word.

Autosport
 - autosport.com, This site is a legend. A bible for racing lovers. News from all around the word. Unfortunately, to get access to all news, interviews and to open the site completely you should be subscribed to Autosport magazine. Anyway, great read.

James Allen on F1
- JA.F1 site (or blog) ovned by ITV Sport’s lead commentator on Formula 1 James Allen

Joe Saward blog
- joesaward is the Joe Saward official blog about Formula 1 world. Joe is an journalist, who write primarily about politics in and around motorsport, specifically on the FIA Formula 1 World Championship

Vital F1
 - vitalf1.com/ is another great site for Motor Sports fan’s like me. Site is relatively new, but great fun, with great discussion forum, Formula 1 news and forum.

 GP update
- f1.gpupdate.net, Site with fresh news from Formula 1

Planet F1
 - planetf1, another site with many different articles, news and statistics. Biased toward British teams, but anyway good read.

Gurney flap
 - gurneyflap.com, Great history site. You can learn a lot from this site. Pictures, cars and many many more. Great.

4mula1
-
4ormula1 is a database of Formula 1 history and statistics of drivers, teams, grand prix, and all results since 1950

Racecar engineering
-Racecar Engineering, an online magazine with a lot to learn from, a lot of technical information’s and explanations

FIA
 - fia.com, La Fédération Internationale de l'Automobile, representing the interests of motoring organisations and motor car users. Head organisation and ruler in auto sport.

Wikipedia
 - wikipedia.org, I don’t believe that I have to tell you anything about this site. It’s not about Formula 1 technology, but you can learn a lot about that too.

Sutton Images

grandprix photo

Carbibles
 - carbibles.com, a great site for normal car users. Here you can find explanations of almost everything about your car and how it works. Technical reviews and explanations of some in-car gadgets.

Dare To Be Different
- Daretobedifferent.org Susie Wolff and UK governing body of UK motorsport have joined forces to launch Dare To Be Different, a high-profile new initiative which is about increasing female participation, not just on the track but in all aspects of the sport.