Caster and camber are two of the most important alignment angles that affect how your car handles, especially on oval tracks. Understanding these angles and how to adjust them will give you more control over your car's performance.
Camber
What is Camber?
Camber is the angle of the tire relative to vertical when viewed from the front of the car. If the top of the tire leans inward (toward the engine), that's negative camber. If the top leans outward, that's positive camber.
Negative Camber: / \
Positive Camber: \ /
Why Camber Matters
When a car goes around a turn, the chassis rolls, causing the tires to lean. The goal of camber is to keep the tire's contact patch flat on the track surface during cornering for maximum grip.
- Right front tire: Needs negative camber because it leans outward in the turn.
- Left front tire: May need positive camber because it leans inward.
- Rear tires: Also use camber, though usually less than the fronts.
Camber Recommendations (Baseline)
| Position | Typical Range | Notes |
|---|---|---|
| Left Front | +0.5° to +1.5° (positive) | Helps keep tire flat when car rolls right |
| Right Front | -2.0° to -3.5° (negative) | Most important camber setting for grip |
| Left Rear | 0° to -0.5° (neutral to slight negative) | Minimal camber, helps with drive off corners |
| Right Rear | -1.0° to -2.0° (negative) | Provides grip on right rear under power |
Adjusting Camber
Camber is typically adjusted by adding or removing shims between the spindle and kingpin, or by adjusting heim joints on the upper or lower links. Always make small changes (0.25° to 0.5°) and test.
To Add More Negative Camber
- Move the top of the tire inward
- On most systems: Add shims to the top link or remove shims from the bottom link
To Add More Positive Camber
- Move the top of the tire outward
- Remove shims from the top link or add shims to the bottom link
Camber and Handling
| Change | Effect on Handling |
|---|---|
| More RF negative camber | More grip in corners (up to a point), can make car tighter if excessive |
| Less RF negative camber | Less corner grip, can make car looser |
| More LF positive camber | Helps car turn in, can make car looser entry |
Caster
What is Caster?
Caster is the angle of the steering pivot (kingpin or ball joints) when viewed from the side of the car. If the pivot leans toward the driver, that's positive caster. If it leans forward, that's negative caster.
Positive Caster: Shopping cart front wheel
Negative Caster: Unstable, rarely used in racing
Why Caster Matters
Caster affects steering effort, straight-line stability, and camber gain in corners. When you turn the steering wheel, positive caster causes the outside front tire to gain negative camber (good for cornering) and the inside front to gain positive camber.
- More positive caster: More steering effort, more camber gain, more straight-line stability.
- Less positive caster: Lighter steering, less camber gain, less stability.
Caster Recommendations (Baseline)
| Position | Typical Range | Notes |
|---|---|---|
| Left Front | +3° to +5° (positive) | Lower than right side to help car turn left |
| Right Front | +5° to +8° (positive) | Higher caster helps camber gain in turns |
| Caster Split (R - L) | 2° to 4° | Right side should have more caster than left |
Caster Split Explained
On oval tracks, we run more caster on the right front than the left front. This is called "caster split." The split helps the car turn left because the right front gains more negative camber as you turn, while the left front doesn't gain as much, creating a dynamic effect that aids turning.
- More caster split (e.g., 7° RF, 3° LF): Helps car turn, can make car looser.
- Less caster split (e.g., 6° RF, 4° LF): Reduces turning assist, can make car tighter.
Adjusting Caster
Caster is adjusted by moving the top of the kingpin forward or backward, or by adjusting the length of the radius rods or trailing arms. On many quarter midgets, caster is adjusted with eccentric cams or by moving the top link forward/backward.
To Increase Caster (more positive)
- Move the top of the kingpin rearward
- Shorten the top link or lengthen the bottom link
To Decrease Caster (less positive)
- Move the top of the kingpin forward
- Lengthen the top link or shorten the bottom link
Caster and Handling
| Change | Effect on Handling |
|---|---|
| Increase RF caster (more split) | More camber gain, helps turn, can make car looser |
| Decrease RF caster (less split) | Less camber gain, can make car tighter |
| Increase both equally | More stability, heavier steering, may feel "slower" turning |
Measuring Caster and Camber
To measure these angles accurately, you'll need:
- Camber gauge: A magnetic or digital gauge that attaches to the wheel hub or rim.
- Caster gauge or turn plates: Caster is measured by turning the wheels and measuring camber change.
Many racers use combination gauges that measure both. Always measure on a level surface with the car at race weight (driver in seat, fuel full).
Baseline Setup Chart
Here's a complete baseline chart for a typical quarter midget on a medium-sized track:
| Angle | Left Front | Right Front | Left Rear | Right Rear |
|---|---|---|---|---|
| Camber | +1.0° | -2.5° | -0.25° | -1.5° |
| Caster | +4.0° | +6.5° | N/A | N/A |
Caster split: 2.5°
Common Mistakes
- Not measuring consistently: Always measure with the same method and same wheel/tire combination.
- Too much RF camber: More than -4° often hurts straight-line traction and tire wear.
- Ignoring caster split: Running equal caster on both sides will make the car harder to turn.
- Not checking after impacts: Even minor contact can change alignment settings.
Summary
Caster and camber are powerful tools for dialing in your car's handling. Start with baseline settings, make small changes, and keep detailed notes. With experience, you'll learn how your car responds and be able to tune for any track condition.
For more information on related topics, see our guides on Basic Chassis Set Up, Cross Weights Explained, and Track Side Chassis Adjustments.