18-inch and 19-inch wheels have similar tire widths, and the rolling radius error is less than 0.4%, which means they should have almost the same footprint. The differences are reflected in the following aspects: 1. From the perspective of braking performance: There is almost no difference in dry braking performance between 18-inch and 19-inch tires, while 19-inch tires perform faster in dry handling. However, 18-inch tires perform best in wet braking performance, and they also excel in cornering hydroplaning. Based on current objective data, there is almost no substantial difference between these two tire specifications. 2. From the perspective of subjective handling: During dry handling tests, the subjective feel of the tires shortens as the size increases. The fastest lap times with 19-inch tires are not because the larger wheel size provides more grip, but because these tires offer sharper and more responsive steering, while 18-inch tires make the car feel softer and less precise. 19-inch tires give the driver confidence and stability. The results of subjective wet handling tests are completely opposite. The confidence and predictability generated by larger tires in dry conditions are replaced by tension and faster loss of grip in wet conditions. Handling with 18-inch wheels is more concentrated at the front, meaning more caution is needed at the rear, whereas switching to 19-inch tires makes the entire car behave indecisively. 3. From the perspective of comfort and noise: 18-inch tires transmit more road bumps to the driver, especially at the rear of the car. The noise level of 18-inch tires is acceptable but noticeable inside the cabin. With 19-inch tires, the car feels entirely different, becoming harsh and offering poor comfort.
