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What Is a Lug Nut?

Acura car wheel with lug nuts

For your vehicle to run smoothly, numerous car parts have to work together in harmony. One such part is the lug nut. This small, humble component plays a big role in helping your vehicle perform as it should.

So, what is a lug nut, and what does it do for you?

What Is a Lug Nut?

A lug nut is a fastener that’s used on the wheel of your car to hold it securely in place. You’ll find lug nuts on everything from cars to vans to trucks; this type of wheel fastener is used on almost all large vehicles with rubber tires.Lug nuts come in different shapes, colors and sizes.

Most lug nuts are made of chrome-plated steel. The chrome plating that covers these lug nuts is designed to resist corrosion. Lighter lug nuts are also available for those who want to minimize vehicle weight for performance or efficiency reasons. These are typically made of titanium or anodized aluminum.

How Does a Lug Nut Work?

Essentially lug nuts are what keep your car’s wheels securely fastened to the vehicle. They do so by screwing onto the wheel studs, threaded rods that are fixed to each wheel hub, which are, in turn, fixed to the axles.

Each lug nut usually nestles into a recessed hole in the wheel, gripping the stud to hold the wheel firmly in place. Most modern cars have five studs and five lug nuts per wheel, but you may see some vehicles with just four, or heavy-duty vehicles with eight or more per wheel.

Types of Lug Nuts

Lug nuts come in many different shapes and sizes. The size and model needed are typically dependent on the car model and the axle that it uses. When deciding which lug nut seat is best for the task, you’ll also need to consider the wheel itself.

Some varieties you might see include:

  • Hex nut
  • Spherical seat
  • Conical seat (probably the most common)
  • Mag type with flat washer
  • Spline drive
  • Open-ended

Are Lug Nuts the Same as Lug Bolts?

Lug nuts and lug bolts serve the same purpose: Both are designed to hold a vehicle’s wheels securely in place.

However, they differ in their design and in the way they attach to a vehicle. A lug bolt is essentially a threaded stem affixed to a head that fits into the socket of a wrench. Think of it as a large screw, or a wheel stud and a lug nut combined into one piece. While a lug nut threads onto a wheel stud that’s (semi-permanently) affixed to the wheel hub, a lug bolt fastens the brake rotor and wheel directly into holes in the wheel hub.

You’ll typically find lug bolts on vehicles made by European brands such as BMW, Audi and Volkswagen.

Which Type of Lug Nut Is Best for My Car?

Your vehicle’s year, make and model are good places to start when identifying the best lug nut for your car. However, you’ll also need to consider the type of wheels the vehicle uses.

Keep these factors in mind when selecting lug nuts:

  • Thread
  • Length/dimensions
  • Seat type
  • Color and finish

What Tools Do I Need to Loosen and Tighten Lug Nuts?

The best tool for loosening and tightening lug nuts is a torque wrench. These tools come in analog and digital varieties, and anyone who dabbles in automotive work should consider keeping one in their garage. Always be sure to tighten to the proper torque specifications outlined by the manufacturer in your vehicle’s owner’s manual.

The bottom line is that lug nuts are what keep your car’s wheels securely fastened, and you rolling down the road smoothly — if one ever goes missing don’t wait to replace it!

Check out all the lug nuts and accessories available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on lug nuts, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.

Warren Clarke View All

I'm a writer and editor who's a regular contributor with the New York Daily News and Carfax, and my content has appeared in over 20 publications. I've written content that covers industries such as automotive, medical, insurance, healthcare, real estate, plumbing, pest control, dental and hospitality.

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