Vehicle door assembly

A vehicle door assembly comprising:

• a window movably mounted on the door assembly for vertical movement between a raised closed position and a lowered open position;
• the window being a single integral window including a lower portion having a generally constant transverse curvature and an upper portion having an accelerated transverse curvature greater than the generally constant transverse curvature of the lower portion, the window including a substantially vertical side edge, the window having a notch located on the side edge of the upper portion of the window;
• a side channel including a lower channel portion having a transverse curvature equivalent to the generally constant transverse curvature of the lower portion of the window, and the side channel having an upper channel portion connected to the lower channel portion, the upper channel portion having an accelerated transverse curvature equivalent to the accelerated transverse curvature of the upper portion of the window;
• the lower channel portion slidably engaging the side edge of the lower portion of the window for guiding vertical movement of the window between the open and closed positions;
• and
• the notch on the side edge of the upper portion of the window matably engaging the upper channel portion of the side channel when the window is in the closed position, the notch on the side edge of the upper portion of the window being spaced apart from the upper and lower channel portions when the window is moved away from the closed position towards the open position;
• whereby the notch enables smooth vertical movement of the window within the side channel.