Toe Angle Calculator Guide - Measurement Steps & Formulas
Tool Overview
This tool allows you to easily calculate the toe angle of front tires on RC cars. Even without an expensive setup gauge, you can calculate accurate toe angles (alignment) by simply measuring the distance between the left and right tires with a ruler.
Main Features
- Calculate toe angle from measured distances (Check current setup)
- Calculate required distance difference from target toe angle (Setup changes)
How to Measure and Adjust Toe Without a Setup Gauge
Calculate from Measurement Mode
Measure the distance between the outer edges of the left and right tires (front and rear) to calculate the toe angle.
- Measure and enter the distance between left and right tires (front, outer edge)
- Measure and enter the distance between left and right tires (rear, outer edge)
- Enter the tire diameter (usually the front-to-rear length of the tire)
- Click the "Calculate" button to display the toe angle
Calculate from Target Angle Mode
Calculate the required distance difference from the target toe angle.
- Enter the desired toe angle (per wheel) (positive for toe-out, negative for toe-in)
- Enter the tire diameter
- Click the "Calculate" button to display the required distance difference
- Adjust the tire position based on the displayed distance difference
Calculation Principles
Toe angle calculation uses geometric relationships.
Terminology
- • F: F (Front Distance): Distance between outer edges of front tires
- • R: R (Rear Distance): Distance between outer edges of rear tires
- • L: L (Tire Diameter): Distance between front and rear measurement points (front-to-rear length of tire)
- • Δ: Δ (Distance Difference): Difference between front and rear distances (Δ = F - R)
- • θ: θ (Toe Angle): Toe angle per wheel
Toe Angle Diagram (Top View)
• F (Front Distance): Distance between outer edges of tires at the front
• R (Rear Distance): Distance between outer edges of tires at the rear
• θ (Toe Angle): Toe angle per wheel (positive for toe-out, negative for toe-in)
• L (Tire Diameter): Distance between front and rear measurement points
Formulas
Geometric Explanation & Handling Characteristics
Assuming that the left and right tires are toed symmetrically by the same angle. Toe settings greatly affect handling characteristics.
トーアウト（Toe-out）
• Δ > 0 (Toe-out): Improves initial steering response and turn-in. Good for technical tracks.
トーイン（Toe-in）
• Δ < 0 (Toe-in): Improves straight-line stability and provides a milder feel. Good for high-speed tracks or beginners.
Reverse Calculation (Distance Difference from Target Toe Angle)
To calculate the required distance difference from a target toe angle, use the following formula:
Frequently Asked Questions
Q: Where should I measure the tire diameter (L)?
Tire diameter represents the distance between front and rear measurement points. Usually, use the front-to-rear length of the tire (tire diameter), but if measuring at the rim or hub center height, enter the front-to-rear distance at that measurement point.
Q: What is the difference between toe-out and toe-in?
Toe-out is when the front is wider (Δ > 0), and toe-in is when the front is narrower (Δ < 0). Generally, toe-out reduces straight-line stability but improves cornering performance. Toe-in improves straight-line stability.
Q: What should I do if the calculation result shows an error?
If the input values are geometrically impossible, an error will be displayed. Please review your measurements and enter the correct values. Especially if the distance difference (Δ) exceeds twice the tire diameter (L), there may be a measurement error.
Q: What happens if the toe angle differs between left and right?
This tool assumes symmetric toe. If the toe angle differs between left and right (one side is bent, servo neutral offset, etc.), the angle of each wheel cannot be uniquely determined from F/R alone. In such cases, you need to measure each side separately.