Steering Wheel Knob: Definition, Uses, 6 Types, 4 Safety Risks, and Legal Rules
A steering wheel knob is a handle mounted on the rim of a steering wheel. This article covers the definition, history, uses, 6 types, mounting methods, 4 safety risks, and legal rules of steering wheel knobs.
What Is a Steering Wheel Knob?
A steering wheel knob is a handle that attaches to the steering wheel rim and allows the driver to turn the wheel with one hand.
According to Wikipedia, other names include spinner knob, Brodie knob, suicide knob, necker knob, granny knob, knuckle buster, and wheel spinner.
When Did Steering Wheel Knobs Become Common?
Steering wheel knobs became popular before power steering, according to Adaptive Dealer.
According to Wikipedia, the knob allowed the driver to crank the steering wheel to make faster turns. According to Adaptive Dealer, drivers also used the knob to spin the wheel rapidly while accelerating, which produced the term "lay a brodie".
Why Is a Steering Wheel Knob Called a Suicide Knob?
The name suicide knob comes from the knob being relatively ineffective for controlling the wheel in an emergency, according to Wikipedia.
The name knuckle buster comes from the wheel spinning back after a turn, which can hit the knuckle, forearm, or elbow of the user.
What Is a Steering Wheel Knob Used For?
A steering wheel knob is used for one-handed steering by drivers with disabilities and by operators of heavy vehicles and equipment. The 3 main uses are listed below.
For related reading, see 2016 Focus RS Headlights Move With Steering Wheel: 5 Fault Causes. The same maintenance context also connects with 2016 Focus RS Headlights Move With Steering Wheel.
- Adaptive driving: A driver works the hand control lever with one hand and steers with the knob hand, according to MobilityWorks.
- Commercial driving: Operators of tractor trailers, forklifts, snow plows, and sanitation trucks use quick-release knobs, according to Quick-Knob.
- Agricultural and recreational use: Golf carts, riding mowers, tractors, and boats use knobs for one-handed turning, according to HY-C.
Who Uses Steering Wheel Knobs for Disability Driving?
People with spinal cord injuries, muscular dystrophy, arthritis, and other conditions use steering wheel knobs together with hand controls, according to MobilityWorks.
According to Wikipedia, common hand controls consist of a push-pull handle mounted below the steering wheel housing. One hand works the controls continuously, so the wheel typically carries a knob for one-handed use.
What Are the 6 Types of Steering Wheel Knobs?
MobilityWorks lists 6 types of steering wheel knobs: ball-style, tri-pin, palm grip, V-grip, single pin, and amputee ring. The table compares the 6 types by grip method and suited driver.
| Steering wheel knob type | Grip method | Suited driver |
|---|---|---|
| Ball-style | Round knob | Drivers who prefer a simple, round grip |
| Tri-pin | Three foam pins | Drivers with minimal gripping strength or reduced wrist stability |
| Palm grip | Broad contact area across the palm | Drivers who do not require wrist support |
| V-grip | V-shaped hand position | Drivers with moderate gripping strength |
| Single pin | One pin | Drivers who cannot open the hand fully |
| Amputee ring | Ring for a prosthetic hook | Drivers with a prosthetic hook |
According to Mobility Engineering, flat, ergonomic, and fork designs also exist.
What Is a Multi-Function Steering Wheel Knob?
A multi-function steering wheel knob performs the functions of a traditional spinner knob and adds switches for secondary vehicle functions.
Bluetooth-programmable models include the Sure-Grip UH360 and the Sure-Grip BB-8, according to Superior Van and Mobility.
How Are Steering Wheel Knobs Mounted?
Steering wheel knobs mount to the rim by 3 methods: clamshell base, screws, and adjustable strap.
- Clamshell base: The base closes around the rim and leaves no permanent marks, according to Living Spinal.
- Screws: Some manufacturers secure a collar to the rim with two screws, according to Hurt Auto.
- Adjustable strap: The strap fits the knob to different steering wheels, according to Quick-Knob.
According to Rehabmart, a quick-release mount lets another driver remove the knob while the mount stays on the wheel.
What Are the 4 Safety Risks of a Steering Wheel Knob?
The 4 main safety risks of a steering wheel knob are airbag projectile injury, wheel kickback, reduced emergency control, and knob detachment.
- Airbag projectile injury: The airbag can launch the knob toward the driver or change how the airbag inflates, according to EVParts4x4.
- Wheel kickback: On vehicles without power steering, road vibrations or potholes can spin the wheel and injure the hand on the knob, according to LegalClarity.
- Reduced emergency control: The knob is relatively ineffective for controlling the wheel in an emergency, according to Wikipedia.
- Knob detachment: Low-priced knobs use cheap plastic and weak hardware that can detach from the wheel, according to The Drive.
How Does a Steering Wheel Knob Affect Airbag Deployment?
A steering wheel knob can become a projectile or change how the airbag inflates during deployment, according to EVParts4x4.
According to LegalClarity, any object attached to the steering wheel hub sits directly over the driver-side airbag. LegalClarity also reports that NHTSA raised the possibility that a knob could rupture an airbag cover or become a projectile.
A Cureus case report documented an aftermarket steering wheel emblem, not a knob, that an airbag projected into a driver's neck and cheek. The report illustrates the projectile mechanism for loose objects near an airbag.
Are Steering Wheel Knobs Legal?
Yes, steering wheel knobs are legal on ordinary US passenger cars, because no state law bans them, according to a 50-state statute review by suicideknob.net.
For a reliable reference point, see NHTSA vehicle safety information.
According to LegalClarity, steering wheel knobs are not universally illegal in the United States, and federal and state equipment and safety rules still apply.
The table lists 4 US rules that affect steering wheel knobs by jurisdiction and requirement.
| Rule | Jurisdiction | Requirement |
|---|---|---|
| 49 U.S.C. 30122 | Federal | Applies to repair shops: an installation that stops the driver-side airbag from deploying correctly violates the rule. |
| OSHA 1926.602(c)(1)(iv) | Federal, construction equipment | Allows knobs only if the steering mechanism prevents road reactions from spinning the handwheel, and the knob sits within the wheel periphery. |
| WAC 296-155-615 | Washington State, material handling equipment | Applies the same two requirements as the OSHA rule. |
| OAR 437-003-3225 | Oregon, highway and road operation vehicles | Prohibits spinner knobs on vehicles without power steering and requires placement on the inside of the wheel. |
Can Police Cite a Driver for a Steering Wheel Knob?
Citations depend on state vehicle code language, because some states require drivers to maintain full control of the vehicle, according to ShipEX.
ShipEX lists Connecticut, Indiana, Kentucky, and Virginia as states with full-control provisions that can limit steering knobs.
According to The Legal Guide, California has no statewide ban, and legality depends on safe operation without interference with airbags or controls. According to Wikipedia, some states allow an accessory knob for drivers who need one because of a disability.
Are Certified Steering Wheel Knobs Available?
Yes, certified steering wheel knobs exist, and Hurt Auto reports a TÜV-tested knob that underwent an airbag firing test and carries a certification number.
What Are the Alternatives to a Steering Wheel Knob?
The 3 alternatives to a steering wheel knob are a steering wheel extension, a secondary mini-steering wheel, and a joystick control.
- Steering wheel extension: The extension carries a spinner knob, tri-pin, or single-pin aid, according to Superior Van and Mobility.
- Secondary mini-steering wheel: The wheel suits users with restricted grip or arm movement, according to Wikipedia.
- Joystick control: The joystick replaces the traditional pedals and steering wheel in extensive adaptations, according to Wikipedia.
What Are Common Questions About Steering Wheel Knobs?
What is a steering wheel knob called?
A steering wheel knob is also called a spinner knob, Brodie knob, suicide knob, necker knob, or wheel spinner, according to Wikipedia.
Why is a steering wheel knob called a suicide knob?
The name reflects the knob being relatively ineffective for controlling the wheel in an emergency, according to Wikipedia.
Can a steering wheel knob be used on a vehicle without power steering?
Oregon rule OAR 437-003-3225 prohibits spinner knobs on vehicles without power steering.
Where does a steering wheel knob mount on the wheel?
Washington rule WAC 296-155-615 requires the knob to sit within the periphery of the wheel on material handling equipment.
How long is a steering wheel knob?
Knob length varies by model, and examples include 4 cm and 6 cm from Hurt Auto and approximately 2.5 inches from Rehabmart.
What Are the Key Facts About a Steering Wheel Knob?
A steering wheel knob is a handle that attaches to the steering wheel rim and allows one-handed turning. The key facts are listed below.
- 6 types: ball-style, tri-pin, palm grip, V-grip, single pin, and amputee ring.
- 3 mounting methods: clamshell base, screws, and adjustable strap.
- 4 safety risks: airbag projectile injury, wheel kickback, reduced emergency control, and knob detachment.
- US legal status: no state ban on ordinary passenger cars, with placement rules for construction and material handling equipment.
Sources:
- Brodie knob, Wikipedia
- Adapted automobile, Wikipedia
- Steering Wheel Spinner Knobs for Disabled Drivers, MobilityWorks
- How Steering Wheel Knobs Help Disabled Drivers Take the Wheel, MobilityWorks
- Choosing the Right Spinner Knob for Your Steering Wheel, Mobility Engineering
- Steering Wheel Spinner Knobs & Driving Aids, Superior Van and Mobility
- Spinner Knob: Sure Grip w/Base, Living Spinal
- Universal Steering Wheel Spinner Knob, Rehabmart
- Steering Wheel Spinner Knob, Hurt Auto
- Steering Controls, Adaptive Dealer
- Best Steering Wheel Knobs: Our Top Picks for Relaxed Driving, The Drive
- Good Vibrations Easy Rider Steering Wheel Knob: Honest Review, HY-C
- Quick-Knob, Quick-Knob
- Are Steering Wheel Knobs Illegal in Your State?, LegalClarity
- Risks of Steering Wheel Knobs for Commercial Vehicles, ShipEX
- Are Steering Wheel Knobs Illegal in California, The Legal Guide
- Are Suicide Knobs Illegal? U.S. State Laws for Steering Wheel Knobs, suicideknob.net
- OAR 437-003-3225, Oregon Public Law
- WAC 296-155-615, Washington State Legislature
- Steering Wheel Aftermarket Rhinestone Emblem Projectile Injury in a Motor Vehicle Collision: A Case Report, Cureus via PubMed Central
- Steering Wheel Knobs: A Complete Guide to Benefits, Safety & Legality, EVParts4x4
Jimmy O’Riley is a UK-based mobile mechanic and automotive diagnostic specialist operating out of Bedfordshire, England. He founded O’Rileys Autos in 2011 with a focus on bringing professional vehicle repairs directly to customers at their homes and workplaces.
With over a decade of hands-on experience, Jimmy specializes in ABS diagnostics, brake system repairs, diesel emissions faults, and DPF cleaning. He is recognized across the UK and Ireland as one of the leading specialists in vehicle braking and emissions systems, earning the title “The DPF King” from his growing online audience.
Jimmy documents real-world automotive repairs through his YouTube channel, which has accumulated over 97,000 subscribers and nearly 2,000 published repair videos. His content covers ABS fault diagnosis, wheel speed sensor testing, brake module replacement, and roadside repair procedures across a wide range of vehicle makes and models.
He is active on YouTube, Instagram, and Facebook under O’Rileys Autos.
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