Rear Track Width Given Roll Rate Calculator

Formula Used:

\[ \text{Rear Track Width} = \sqrt{\frac{\text{Roll Rate} \times \text{Wheel Centre Rate} \times \text{Spring Track Width}^2}{\left(\frac{\text{Wheel Centre Rate} \times \text{Spring Track Width}^2}{2} - \text{Roll Rate}\right) \times \text{Tyre Vertical Rate}}} \]

Roll Rate (KΦ):

N·m/rad

Wheel Centre Rate (Kw):

N/m

Spring Track Width (Ts):

Tyre Vertical Rate (Kt):

N/m

Rear Track Width (tR):

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1. What Is Rear Track Width?

Rear Track Width is the distance between the centers of the rear wheels. It is a critical parameter in vehicle dynamics that affects stability, handling, and overall performance.

2. How Does The Calculator Work?

The calculator uses the formula:

Where:

Roll Rate (KΦ) — Resistance moment generated per unit of roll angle (N·m/rad)
Wheel Centre Rate (Kw) — Vertical force per unit vertical displacement at wheel centerline (N/m)
Spring Track Width (Ts) — Distance between springs on either side of axle (m)
Tyre Vertical Rate (Kt) — Spring rate controlled by tyre compound and stiffness (N/m)

Explanation: This formula calculates the optimal rear track width based on suspension characteristics and tyre properties to achieve desired vehicle dynamics.

3. Importance Of Rear Track Width Calculation

Details: Proper rear track width calculation is essential for vehicle stability, cornering performance, weight distribution, and overall handling characteristics. It helps optimize the vehicle's roll center and suspension geometry.

4. Using The Calculator

Tips: Enter all values in appropriate units (N·m/rad for roll rate, N/m for rates, m for distances). Ensure all values are positive and the denominator in the formula remains positive for valid results.

5. Frequently Asked Questions (FAQ)

Q1: Why is rear track width important in vehicle design?
A: Rear track width affects vehicle stability, cornering ability, and overall handling performance by influencing the vehicle's roll center and weight distribution.

Q2: How does roll rate affect rear track width?
A: Higher roll rates generally require wider track widths to maintain optimal vehicle dynamics and prevent excessive body roll during cornering.

Q3: What is the relationship between spring track width and rear track width?
A: Spring track width is a component in the calculation that influences the final rear track width determination through the suspension geometry.

Q4: Can this calculator be used for front track width?
A: While the principles are similar, front suspension dynamics may require different calculations due to steering geometry and different weight distribution.

Q5: What are typical values for rear track width in passenger vehicles?
A: Typical rear track widths range from 1.4m to 1.6m for most passenger vehicles, though this varies significantly based on vehicle type and purpose.