Named after "bridge jumper" Steve Brodie (1863-1901), a brodie knob (alternate spelling brody knob) is a knob that attaches to the steering wheel of an automobile. The knob swivels, and is intended to make steering with one hand less difficult. Brodie knobs are also known as necker knobs, because they allow steering with one hand while necking with the passenger. One disadvantage of the knob is that after letting go of the steering wheel after going around a corner, the steering wheel spins rapidly and the knob can hit the user's forearm or elbow. Other names include suicide knob, granny knob, and steering wheel spinner.
Brodie knobs enjoyed limited popularity on trucks and tractors before the advent of power steering. Their main use today is still in trucks, particularly semi trucks where they allow simultaneous steering and operation of the radio or gearshift. They are also used on forklifts and riding lawnmowers, where frequent sharp turning is required. The knob is also standard equipment in most modern farm and commercial tractors, its main purpose being to ease single-hand steering while the driver operates other controls with his/her other hand or is traveling in reverse.
Wheel-spinners are also used by people with disabilities to drive automobiles.
Brodie knobs are legal in most or all states of the USA for private vehicles as most states have not addressed this steering attachment in law. In New York State, however, a doctor's prescription for a spinner now must be submitted to the NYSDMV, which in turn, shows that the knob is "required" on all vehicles the user drives and such requirement is entered on the user's drivers license. There is a USA federal labor law restricting their use for specific construction vehicles; although hydraulic driven power steering vehicles may not fall under this category.
Decorative versions of brodie knobs are also available. Popular designs include chrome-plated and 8 ball.
Brodie knobs were widely popular, especially on the west coast of the US during the 1950s. Their primary use was on Hot Rods. The knob was used to spin the steering wheel, rapidly in one direction or the other, while accelerating, to cause the tire(s) to spin while rapidly whipping the car 180 degrees or half of a "doughnut". Hence the term "lay a brodie". In the 1950s and '60s "Pep Boys" offered a large variety of brodie knobs, with every conceivable theme, from "Candy Apple colored", "Product Logos", to "nude women," and everything in between. Some automobile dealerships used them for advertisements. They were useful when power steering was rare.