Camber Crutches

The use of unusually high or low amounts of camber in the front suspension can be an indication of a setup designed incorrectly. If we need to set abnormal camber settings, we need to look for the true cause of the problem instead of crutching the setup.

If you have ever been to a big race that attracts racers from different regions, you might have noticed a wide range of camber settings for different cars. Some might have two degrees in the right front, while others will have what appears to be more than five or six degrees of camber in the right-front wheel. Each team sets up its car with what they think is needed, based on their experience with that car. We can also correctly assume that the suspension design on each of the cars must be different from one another.

Using excessive or deficient camber in either of the front wheels can be one of those racing crutches that mask the real problem. It usually means the car has setup and/or geometry design problems that are causing too much weight transfer or incorrect camber change during cornering. One of the most important ingredients for the total handling package is a front-end setup for proper camber change characteristics to go along with a balanced setup that will distribute the weight correctly in the turns.

In our discussion, to keep the confusion factor down, we will refer to the "outside" of the tire, meaning the side toward the outside of the turn, whether the tire is on the right side or the left side. "Inside" means the side of the tire to the inside of the racetrack.

We need more negative camber if the right-front tire is hot on the outside. We can usually adjust our front tire cambers so that the heat will be relatively even across the tire after a good, hard run. How do we know if we have the best design for camber change and, above all, the best setup?

There are two things that can cause a tire to need more or less static camber: a setup that promotes excess weight distribution to the right-front tire and less retained weight on the left-front tire, or incorrect control arm angles so that when the suspension moves in dive and roll, the wheel changes camber in either the positive or negative direction relative to the track surface.

The most useful definition of camber change is the deviation from the static camber that happens when the car enters and negotiates a turn. This involves a combination of dive and roll of the chassis. The number of degrees of camber that the front wheels lose or gain relative to the racing surface from static (down the straightaway) to dynamic (in the middle of the turns) chassis attitude is true camber change.

We used to measure camber change as the number of degrees of change the wheel has in each inch of bump. We would place the car on jackstands, jack up the wheel, and record the camber at each increment, usually each inch, of vertical movement. Knowing the camber change per inch did not really tell us anything about the design. We could assume that a certain "camber change" was correct, but was it? We have since learned to look at camber change just the way the car experiences it, using a combination of chassis dive and roll.

There is an optimum amount of true camber change for each of the front wheels, based on the type of race car, the magnitude of lateral traction affected by the tire's track and surface composition (lateral G-forces), the amount of track banking angle, and the setup in the car. Unfortunately, we cannot design a suspension that will have the correct camber change for a variety of conditions. We can design a car so that we can adjust the camber change characteristics to suit a number of known conditions, as in different racetracks and their setups.