Illustrated Explanation of Carriage Construction: Volume I

Having corrected the error, it seems one should not hastily alter the three clear passages in the Rites of Zhou and the Record of Trades merely because an ancient manuscript used the character zhou zhou: typically the carriage shaft, though here used as a variant or error for the hub-opening in a slightly novel way. The three clear passages are: The Rites says: "The Great Charioteer offers sacrifices to the two zhi original: 軹; the outer ends of the axle or hub"; and the Record of Trades where the Record says: "The zhi is three feet and three inches high," and also, "Subtracting three parts makes the zhi."

If one is concerned that this might be confused with the zhi located inside the carriage frame, consider the following: the wheel spokes are called zhou and the ribs of the canopy are also called zhou; spokes have zi tenons and zao mortises/ends, and canopy ribs also have zi and zao; the wheel track is called gui, and the revolving axle-head is also called gui; the carriage side-timbers are called yi, and the carriage linchpins are also called yi. In all these cases, a single name is applied to two different parts, yet there is no concern about confusion. Synthesizing these various meanings, it seems most stable to use the character zhi.

Wheel spokes are called fu fu: the spokes of the wheel

The Record of Trades states: "As for the spokes, they are intended to point straight connecting the hub directly to the outer rim." In antiquity, one wheel consisted of thirty spokes. The Laozi The Tao Te Ching states: "Thirty spokes share a single hub." The Huainanzi A Han Dynasty philosophical text in the chapter "Instructions on Peaceful Kinship" states: "The wheel does not turn [on its own], yet each of the thirty spokes contributes its own strength." The Records of Ritual of the Elder Dai in the chapter "On Protecting and Tutoring" states: "The thirty spokes symbolize the thirty days of the lunar month..."