Simply begin typing or use the editing tools above to add to
this article. Once you are finished and click submit, your
modifications will be sent to our editors for review. Bicycle
wheels have a rim to retain the tire, a ball-bearing hub, and
spokes between hub and rim. Spokes are made of steel wire, laced
tangentially and kept under tension by threaded nipples in the
rims that are adjusted to keep the rim straight (true). Hub
axles are held in the frame either by nuts or by a cam-action
(quick-release) lever. Spoked wheels appeared about 2000 bc,
when they were in use on chariots in Asia Minor. Later
developments included iron hubs (centerpieces) turning on
greased axles, and the introduction of a tire in the form of an
iron ring that was expanded by heat and dropped over the rim and
that on cooling shrank and drew the members tightly together.
...were Indo-European tribesmen, speaking languages akin to
Sanskrit, who already possessed horses. About 2000 bc people on
the Western Steppe or in Mesopotamia, Syr