If you own a car, you're probably familiar with the chore of getting it serviced. Unless you're a mechanic, you may not realize the significance of all the maintenance that's necessary. Take wheel alignment for instance. Experts recommend one every 10,000 miles (16,093 kilometers) or so. But exactly what does this mean, and why is it important?
Wheel alignment involves adjusting the angles of your wheels to achieve optimal handling for your vehicle. The wheels can be jolted out of alignment when you knock them against curbs -- or when you get in an accident. The effect on the wheel may be so slight that you may not even be able to tell by looking at it. You might feel the effect if your car pulls one way or the other when the you're driving straight ahead. Even when you can't feel it, out-of-whack alignment still wears on your tires.
Turns out, your wheels can be off kilter in a few different ways. Camber is one of them and refers to the vertical tilt of a wheel if you're looking at it from the front or rear of the car. A wheel has zero or neutral camber if it's perfectly perpendicular with the level ground. If the top of a wheel is tilted outward from the vehicle and the bottom slopes in, the wheel has positive camber. Conversely, if the top of the wheel is tilted toward the vehicle and the bottom slopes outward, it has negative camber.
Oddly enough, zero camber isn't always best. Manufacturers build the average street car with slightly positive camber. Race cars use even sharper camber or tilts. If you're a NASCAR driver, why would you want your camber out of kilter? Find out next.
The Effect of Camber in NASCAR
Achieving optimum camber is all about improving tire grip. Driving on icy or muddy roads can quickly teach you the importance of grip. When your tires lose it, you'll have less control of the vehicle. Even in dry conditions, the camber or angle of your tires has a lot to do with how well they grip the road. The more surface area between your tire and the road, the better the grip and the more stability you'll have.
Ideally, the tread surface of each tire will be flat relative to the ground. But most streets aren't completely level -- they're sloped a little. Because of this, slightly positive -- we're talking maybe half a degree -- rather than zero camber will give you optimum surface contact and grip [source: Brand]. That is, as long as you're driving straight ahead. Making a fast turn will change things.
To understand how turns change the game, imagine a car with zero camber on a perfectly level road. When it makes a sharp left, the car -- tires included -- will tilt to the right. At this point, the wheels' camber is no longer zero relative to the ground. The tilted tires are now sharing less surface area with the road and consequently have less grip.
When performance drivers want maximum cornering control, they put negative camber on all wheels. This way, during a turn, the entire tread surfaces of the outside tires -- which carry more weight than the inside ones -- achieving optimum grip. For those who want to increase street cornering performance, experts recommend a half a degree of negative camber [source: Alexander]. But since cornering performance is especially important for a race car, each of its wheels has a steeper angle of negative camber.
Notice that with negative camber, the inside wheels still lose surface area during a turn. But, as we said, ideal handling includes all tires being flat relative to the ground. On the street or on road courses with left and right turns, this isn't possible, and negative camber ends up being the best compromise.
On oval NASCAR tracks, however, where race cars make only left turns, things are different. With left turns, NASCAR cars use negative camber for the right wheels, which will always be on the outside of a turn. For the left wheels, they use positive camber, because those wheels will always be on the inside of a turn. With this ideal cornering combination, NASCAR race cars can have optimal grip and stability during a turn and thus maximum corning speeds.
Determining the best angle can depend on a few different factors, and getting the right balance can be difficult. For example, if the track is banked -- sloped inward at the corners -- then you probably don't need much camber. But too much of it has disadvantages. For instance, with excessive camber, you have less grip on straightaway driving -- meaning slightly worse acceleration and braking when a car isn't in a turn. Camber also wears on the lower edges of a vehicle's tires when driving straight, which can lead to blowouts [source: Briggs].
If you're revved up for even more NASCAR and auto-related subjects, take a look at the links on the next page.
Related HowStuffWorks Articles
More Great Links
- Alexander, Don. "High-Performance Handling." MotorBooks/MBI Publishing Company. 2002. (Nov. 7, 2008)http://books.google.com/books?id=BJUVdn5SMBgC
- Brand, Paul. "How to Repair Your Car." MotorBooks/MBI Publishing Company. 2006. (Nov. 7, 2008)http://books.google.com/books?id=KKj9sX8G_94C
- Briggs, Josh. "How NASCAR Tire Technology Works." HowStuffWorks.com. Aug. 25, 2008. (Nov. 7, 2008)https://entertainment.howstuffworks.com/nascar-tire.htm
- McKeever, Danny. "What is the 'camber' of a tire in auto racing?" VideoJug. (Nov. 7, 2008)http://www.videojug.com/expertanswer/auto-racing-jargon-2/what-is-the-camber-of-a-tire-in-auto-racing
- McReynolds, Larry. "Camber considerations." MSN/FOX Sports. Sept. 10, 2005.(Nov. 7, 2008)http://msn.foxsports.com/nascar/story/4829776/Camber-considerations
- NASCAR.com. "NASCAR Glossary A-D." (Nov. 7, 2008)http://msn.foxsports.com/nascar/story/4829776/Camber-considerations