What is the Circle of Traction?
Racing is full of secrets and tribal knowledge until we learn. The circle of traction theory shows the maximum traction a tire can provide. It’s visualized as a circle representing the tire’s traction limits. When a tire contacts the racing surface, it forms a contact patch. This patch is influenced by the load on the tire. Moreover, traction increases with vertical load up to a point. However, additional load offers diminishing returns.
Images courtesy of RacingPartSales.com
Forces Affecting Traction
- Acceleration Force:
- The force applied via the accelerator pedal moves the contact patch along the acceleration force line (red line) in the circle.
- More force pushes the patch towards the tire’s limit, the circle’s edge.
- Steering Input:
- Steering inputs (blue line) shift the force along the turning force line.
- The intersection of these forces determines the patch’s position within the circle.
- Braking Force:
- The force applied when braking moves the contact patch along the braking force line (yellow line) in the circle.
- Braking force, combined with acceleration and steering forces, influences the tire’s total traction capability.
- This impacts control and stability.
Losing Traction
Extreme forces, such as full throttle or full-lock steering, can push the contact patch outside the circle. When this happens, you lose control. For example, try driving in a circle in an empty parking lot. Gradually increase throttle until the tires squeal, then back off slightly. Maintain this speed and apply the brake. The tires will squeal again as braking force combines with acceleration and turning forces. This exceeds the traction circle.
Maximizing Traction for Fast Laps
- Braking Before the Apex: Fast laps are achieved by braking before the corner’s apex.
- Settling the Car: Let the car settle back onto the suspension before negotiating the turn.
- Accelerating Post-Apex: Accelerate after the turn to maximize traction since fewer forces are applied simultaneously.
Contact Us
For more tips on utilizing unused traction, visit us at StreetStockTech.com.
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