How to Calculate Camberby James Porter
Camber refers to the vertical angle of tires on a car relative to the road surface when viewed from the car's front. Camber is very important with regard to the way the car handles turns. Generally, a car will handle best when the force from its tires down onto the road is perpendicular to their alignment. Adjusting camber can greatly improve (or detract from) this handling, so measuring and calculating camber is a valuable tool.
Method 1: Direct Measurement
Set a straight-edge vertically along the tire you want to measure. The ruler should be resting flat against the tire's surface with its bottom edge on the ground. It does not need to be in the middle of the tire as long as it is not rotated relative to the ground.
Position a protractor on the ground against the straight-edge so that its length extends away from the tire and its surface is against the edge of the straight-edge. Align it so that the straight-edge crosses through the protractor's center reference point when viewed head-on (from the protractor). If the tire is in the way of this, you can either hold the straight-edge away from the tire but still parallel to it, or move the protractor to the side of the tire but still perpendicular to it.
Look through the protractor head-on, making sure the straight-edge crosses through its center reference point from your perspective, and measure the angle of the straight-edge.
Determine the camber angle of this measurement. A camber angle of zero is straight up and down, which should correspond to 90 degrees on the protractor. The camber angle is therefore the difference between your measurement and 90 degrees. If the top of the tire goes in towards the car, that's a negative camber. If it goes out, that's a positive camber.
Method 2: Trigonometric Calculation
Use the ruler or tape measure to measure the vertical distance from the top of the tire to the ground.
Measure the horizontal distance from the bottom of the tire to the same place on the ground from Step 1. It is important in these two steps that the two places on the top and bottom of the tire used in these measurements are at the same spot along the width of the tire. In other words, they should make a line parallel to the alignment of the tire.
Divide the horizontal measurement by the vertical one with a calculator then take the inverse tangent (usually denoted by "Tan" with a small "-1," or by "Arctan" or "Atan"). Make sure the calculator is in degree mode and not radian mode. The result is the camber angle. As described in the first method, if the top of the tire goes in towards the car, that's a negative camber. If it goes out, that's a positive camber.
Things You'll Need
- Ruler or tape measure
- Scientific calculator
- These methods are fine for amateur purposes or satisfying curiosity, but for professional-level measurements you will need to be more exact and take into account other factors. Have the camber measured by a mechanic.
Hailing from Port Townsend, Wash., James Porter has been writing informational online content since 2010. His articles on physics and chemistry have been published on eHow. Porter holds a Bachelor of Science from Evergreen State College, with a broad focus covering computer science, chemistry, physics, and music.