A spinner knob -- also known as a suicide knob or brody knob -- is a round steering aid that attaches to your vehicle's steering wheel allowing the driver to more easily steer with one hand. Spinner knobs were quite popular from the 1940s to the 1960s, but today, many drivers are unsure whether it is legal to use this device. Few states prohibit all uses of the spinner knob, but some have installation requirements or restrict how the device can be used in commercial settings.
The federal Occupational Safety and Health Administration, or OSHA, permits the use of spinner knobs in earth-moving equipment, such as bulldozers and off-road trucks, only if the knobs do not react to road conditions by involuntarily spinning. For example, if the steering wheel spins when you let go of the knob, it is considered by OSHA to be unsafe. To comply with federal regulations, the spinner knob must be installed on the inside of the steering wheel because if installed on the outside, it's possible your clothing could catch on the knob and interfere with safe operation of the vehicle.
Use of Spinner Knobs in Commercial Settings
In addition to OSHA's regulations, some states restrict the use of spinner knobs on vehicles used in construction and on mechanical equipment. For example, state-funded Central Michigan University's Powered Industrial Trucks Program regulates the use of spinner knobs on forklifts. A spinner knob cannot be attached to the steering wheel unless the truck was originally equipped with a knob.
Like most states, Michigan does not prohibit the use of spinner knobs, and Kentucky simply prohibits the use of all defective steering devices, so a broken or improperly installed spinner knob would be in violation of state law. The state of Washington prohibits a steering device or wheel attachment if a driver's clothing or jewelry could catch on it during normal driving.
Use of Spinner Knobs by Disabled People
Some drivers cannot use a standard steering wheel because of physical limitations. A few states allow the use of spinner knobs by drivers who otherwise could not operate a vehicle because of a disability. In Michigan, a person who cannot use a standard steering wheel can be granted a restricted driving permit contingent on the use of a spinner knob. In New York, a driver must be able to steer with at least one hand or prosthetic device; the state does not ban spinner knobs, and the device could help a disabled person comply with New York's one-hand steering requirement.