Understanding Your Grade
Your grade evaluates the geometric perfection of the thumbstick module's outer boundary.
A+ (Esports Ready) means the stick achieves a flawless circle, critical for consistent diagonal movement in games like Apex Legends and Rocket League.
F (Defective) indicates severe asymmetry, meaning diagonal inputs will hit their max value prematurely or not at all.
Since you're using a Xbox Series X|S with a Potentiometer module, you can expect the underlying tech to be prone to slight asymmetry and physical wear.
Xbox Series controllers are the reference for the classic "squircle" pattern: the stick housing is nearly square and the thumbstick rubs its gate at the diagonals, which produces the well-known slight circularity pinch on every unit. Because the gate geometry causes it, the pattern is expected on both sticks and both axes — a low grade here is a replacement signal only when the pinch is strongly asymmetric or accompanied by visible stick wobble.
Potentiometer (pot) sticks read position from a wiper sliding over a carbon track, and that friction is exactly where circularity degrades over time. A fresh pot module can trace a near-perfect circle, but as the track wears, the wiper loses contact at certain angles and the ring starts to pinch into a squircle — usually first visible near the 45-degree diagonals. Wear is rarely symmetric between the X and Y axes, so a lopsided grade on a pot module is the classic signal that the stick has been played past its best range and is a stronger candidate for replacement than for recalibration.
Pot modules degrade along a predictable path: the carbon track wears where the stick spends the most time, so the ring pinches first at your dominant input angles, and the wiper's lost contact produces small flats on the circle before full drift appears. Because the wear is physical, no software setting can restore the geometry — recalibration only recenters the zero point, it cannot grow the worn track back. A lopsided grade between the X and Y axes on a pot module is therefore the most reliable hardware-wear signal this tester can show, and the replacement decision is generally clear once the ring shows a visible flat.
For the Xbox Series pad, the squircle pinch is baked into the gate geometry, so treat an even A/B+ as expected and reserve judgment for one-sided results. A common real-world pattern on well-played Xbox units is a wear notch at the 4 and 8 o'clock positions from years of left-stick forward input — that shows up as a local ring dip rather than a uniform shrink, and it is a clear replacement signal. Also check stick wobble before grading: a loose collar creates a blurred, wide ring that reads as poor circularity even with healthy sensors.
Xbox controllers are produced in large volume across several factory batches, and community teardowns note that stick module quality varies between production runs, so a low circularity grade is worth confirming with a second sample from a different unit before you treat it as a design issue. The squircle gate pinch is present on every unit, but a healthy one still grades within the A or B band — a grade that drops into the C range with an even, symmetric ring is more consistent with a firm gate than a failing sensor. Because the gate itself shapes the reading, the same Xbox pad can grade differently after the stick collar wears in, so re-run the test at the same stick angle each time you compare runs.