What Are Camber, Caster, and Toe?
Understand the three angles that put your wheels where they need to be.
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When a vehicle is out of alignment, perhaps due to wear over time or recent suspension work, it means the wheels aren't sitting properly relative to the body. This can lead to issues with tire wear, handling, braking capability, and high-speed stability, so it's not something to leave unresolved.
When you take your car in to get aligned, the mechanic will determine what suspension adjustments to make after looking at three important angles — camber, caster, and toe — which together indicate if the wheels are in their proper positions.
Here we explain each in detail.
Camber
How It's Measured
Camber is perhaps the easiest of the three angles to see. It describes how far the wheels/tires lean away from a perfect upright position. You can see it best while looking at the car head on, either at the front or rear. When the top of the wheel tilts inward, that's negative camber. If it leans outward, it's positive camber. Factory alignments tend to call for zero degrees to -1 degree of camber.
What Camber Affects
The camber angle directly affects the size and shape of the tire's contact patch. As a result, it impacts things relating to grip — cornering, acceleration, and braking — or the main functions of the tire. Camber also has an effect on tire wear; too much one way or the other, and the rubber will wear unevenly.
Caster
How It's Measured
Caster describes the angle between the wheel centerline and the car's upper steering pivot as measured from the side. If you need a visual, imagine a bicycle; draw a vertical line through the wheel center and another from the top of the front fork to the wheel center. The angle formed by those lines is the caster.
Positive caster places the wheel center ahead of that pivot point, while negative caster places it behind. All cars have some amount of positive caster angle, or else they'd be uncontrollable. (Imagine trying to steer a bicycle with its front fork pointing rearward.)
What Caster Affects
Caster angle has a big impact on a vehicle's steering and how stable the vehicle is at high speed. More caster angle generally means better stability, but it comes at the cost of some steering response, so the angle is a compromise based on the intent and use of the vehicle.
Toe
How It's Measured
Toe is best understood by looking down at your feet. It describes the angle between the wheels and straight ahead when viewed from above. If the front of the tire points in (think pigeon-toed), that's toe in. If it points out (think duck-footed), that's toe out.
What Toe Affects
Automakers generally set toe to a neutral position, close to zero, on road cars. This makes sense, as the wheels want to be parallel to avoid working against one another as the car travels straight. If the toe angle is too large one way or the other, it will result in unnecessary tire wear and decreased fuel economy, as the tire will waste energy trying to follow a different path than the vehicle.
Manufacturers set up the suspension with a factory alignment that is safe and meets most people's needs. So when you take your car to get aligned, the shop will look up these figures and use them to put everything back into, well, alignment. If you've modified or replaced the suspension, the angles may change — which you may want, for example, on a track-prepared vehicle. Note that these angles often differ between the front (steering) axle and the rear axle, and they can even differ from one side of the vehicle to the other.
