Invention of the Wheel
Most authorities credit the ancient Mesopotamians (Sumerians) with the invention of the wheel at about 4000 BCE, with an independent invention in China at around 2800 BCE.
In the Near East, these were composite disk wheels were made up of three wooden planks held together by struts. The central section was approximately twice as large as the outer two. held together by slats. Hub and axle ends and lynch-pins seem to point to wheels that already revolved on affixed axles. Spoked wheels first appeared in Anatolia (Turkey) around 1,900 BCE and soon spread to Egypt.
Early 3rd Millennium BCE: Equines Join Oxen as Draft Animals
Oxen had already been yoked to the pole of a plow, probably early in the forth millennium BCE, in the Near East. Towards the end of the millennium they are yoked to sledges, which were eventually mounted on rollers and then on wheels. Vehicles with disk wheels appear near the beginning of the third millennium BCE and are depicted as drawn also by equids - either donkeys or onager hybrids. The four-wheeled war wagon depicted on the "Standard" from Ur, in southern Mesopotamia, of about 2,500 BCE, is pulled by a yoke team of four equids with nose-ring control.
By the early 18th century BCE, numerous horses had been brought Near East from the north and a light chariot with spoke wheels had been developed for war and hunting. Yoked to it, the horse now superseded other equids in harness for these purposes - although not for the less glamorous types of draft. In China, horse drawn war chariots were in use during the Shang Dynasty (circa 1,400 BCE).
The Yoke: Better for Oxen than Horses
In many ancient civilizations the horse was used primarily as a harness animal for almost 1,000 years. From the early second millennium to the early first millennium BCE equine draft was preceded by and modeled after a draft system developed for oxen. This system was not well-adapted to equine anatomy.
Throughout antiquity horses continued to be harnessed in pairs, with the horses on either side of a pole and under a yoke. The yoke was secured by a strap around the horse's throat and tended to press on the windpipe. By the 15th century BCE in Egypt, we find a means of better adapting the yoke to the anatomy of equids, in the form of a yoke saddle. This was a wishbone-shaped wooden object, lashed to the yoke by its "handle," with its "legs" lying along the horse's shoulders and thus taking considerable pressure off the throat. The yoke saddles rested on pads and their ends were joined by crescent-shaped straps that went across the lower part of the horse's throat.
Anatomy of an Ancient Wheel: circa 1,600 BCE
The hub of an ancient Egyptian wheel utilized very intricate joinery in its construction. The spokes were created in halves, and half of one spoke was made of the same piece of wood as half of the adjoining spoke. In this way the spokes became an integral part of the hub. In terms of design, relative to available materials, the Egyptian wheel is a remarkable technological achievement.
Egyptian Wheelwrights Strive for a More Perfect Wheel
By 1600 BCE, spoked chariot wheels were fully developed. A 15th-century BCE mural from the tomb of Hapu in Egypt, shows a chariot-maker's workshop. In the upper register, the felloe (the rim of the wheel supported by spokes) of a wheel is being planed. The Egyptian wheel was very light and derived its strength from its special design, as described above. Several different woods were used in the making of chariots, some of them, such as elm, imported from as far away as northern Syria.