Mailbag: Explaining Thrust Angle for Both Street & Race Vehicles

Q: What exactly is the “thrust angle” on a vehicle, and why does it matter?

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A: The thrust angle is an imaginary line that is precisely 90 degrees from the rear axle center line.

It compares the direction the axle is pointed to the center line of the vehicle.

Why is thrust angle important?

For street vehicles, the thrust angle must be aligned with the vehicle centerline, ensuring that the vehicle travels in a straight line and handles predictably.

For solid-axle vehicles, the thrust angle being off could signal that the frame is bent. On vehicles with independent rear suspension, incorrect toe angle settings can cause thrust angle misalignment.

Thrust Angle in Circle Track Racing

In circle track racing—especially dirt track racing—the thrust angle can affect what is called “rear steer.”

The thrust angle is typically adjusted based on track conditions. Combined with other suspension adjustments, thrust angle can help (or hurt) the racecar’s handling and make the car faster (or slower) around the track.

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This is another in a series of weekly Q&A Mailbag sessions with the Summit Racing tech department, in which there are hundreds more. Click here to see them all.