Turntable
Smoothly rotates the tire or measurement jig to read the actual steering angle for each side.
Caster angle calculator
CASTER ANGLE CALCULATOR
Caster Angle Calculator
Automatically calculates the caster angle from the change in camber angle when steering left and right. Since you can enter the steering angle for each side as measured on the turntable, calculations can be performed even if the actual measured angles are not exactly the same.
Enter Measured Values
°
°
°
°
For the camber angle, enter a positive value when the top of the wheel tilts outward from the vehicle and a negative value when it tilts inward, using the same sign convention for both sides.
Calculated Caster Angle
Waiting for input
Effective factor at these steering angles: approx. 1.462
Watch the measurement procedure in the video
Caster angle measurement with a dummy wheel
This CG video demonstrates the procedure for reading the steering angle and camber angle using a digital angle gauge and turning radius gauge.
HOW IT WORKS
Caster Angle Calculation Method
The caster angle is calculated from the difference in camber angle that occurs when steering left and right. This page uses trigonometric functions to calculate the angle using the entered actual steering angles for each side, rather than relying solely on a fixed factor.
Caster Angle = asin(|sin γR − sin γL| ÷ (sin θL + sin θR))γL/γR: Camber angles when steering left/right ／ θL/θR: Steering angles left/right
The effective factor when steering 20° left and right is approximately 1.462. If the angles differ between the left and right sides, enter the angles measured on the turntable separately.
EQUIPMENT
Items required to measure the caster angle
Angle Gauge / Camber Gauge
Measures the camber angle at the position reached when steering left and right. Check the zero point before measuring.
Dummy Wheel / Hub Stand PLUS
Facilitates measurement relative to the hub and reduces the effects of tire or wheel deformation and runout.
Level Measurement Environment
Align the floor height and vehicle attitude for both sides. Any leveling discrepancy directly affects the measured values.
MEASUREMENT PROCEDURE
Caster Angle Measurement Procedure Using a Dummy Wheel
- Prepare the measurement environmentInstall the turntables level on both sides and set the vehicle to the load and ride height used during measurement.
- Check the zero point of the measuring deviceInstall the angle gauge in a straight-ahead position and check the mounting surface and sign direction.
- Steer left and recordSteer left to near the target angle, then record the actual steering angle and camber angle.
- Steer right and recordSimilarly, steer right and record the actual steering angle and camber angle.
- Enter the four measured valuesEnter the steering angles and camber angles for each side into the calculator.
- Check repeatabilityMeasure again under the same conditions and check for variations in the values.
ACCURACY & REPEATABILITY
Key Points for Improving Measurement Accuracy and Repeatability
Even if the calculation formula is correct, results will vary if the floor, steering angle, or measuring device setup changes. It is important to check not only the absolute value but also whether the same procedure returns the same value.
Floor and Vehicle Attitude
Align the heights on both sides and avoid changing the ride height or load conditions during measurement.
Use the Actual Steering Angle
Enter the measured values rather than the target values. Calculations can be performed even if there is a difference between the left and right sides.
Measure Multiple Times
Allow the vehicle to settle after steering, then measure 2–3 times using the same procedure.
This tool is an aid for calculating angles from entered values. Follow the instructions for each product regarding measuring device calibration, vehicle safety, and the allowable load and use of jacks and stands.
FAQ
Frequently Asked Questions About Caster Angle Measurement
Are you measuring the caster angle directly?
Rather than measuring the angle directly, it is calculated from the change in camber angle and the steering angle that occur when steering left and right.
Must the steering angle be 20° on both sides?
20° is one common measurement condition, but this calculator allows you to enter the actual steering angle for each side.
Can it be calculated even if the steering angles differ between the left and right sides?
Yes. Enter the left and right steering angles separately and calculate using each angle.
How should the sign of the camber angle be entered?
Enter a positive value when the top of the wheel tilts outward from the vehicle and a negative value when it tilts inward.
Can it be measured with regular tires and wheels?
It can be calculated if the steering angle and camber angle are correctly obtained. However, tire deflection or wheel runout may affect repeatability.
What is the advantage of using a dummy wheel?
It allows measurement relative to the hub and makes it easier to eliminate tire deflection. It also provides easier access to the adjustment area, making it suitable for repeating measurement and adjustment.
※ The displayed values are calculation results based on the entered values. In vehicle maintenance, manufacturer specifications, maintenance procedures, and safety standards take precedence. The content of this page may be updated based on the results of measurement tests.