What Are Lug Nuts On A Tire & What Do They Do? [With Types And Pictures]

Did you hear a mechanic refer to lug nuts and wonder what they are and what they do for your tires? Wonder no more, because we have researched this question and have the answer for you.

Lug nuts are the nuts that secure the wheels on your car. You install them over the stud bolts of each wheel.

We'll talk about the different types of lug nuts in the succeeding sections. Read on!

What Are Lug Nuts?

Vehicles that use rubber tires will have lug nuts to secure the wheels on the vehicle. A lug nut is a type of fastener made specifically for fastening wheels that use wheel studs instead of lug bolts.

Wheels that use lug bolts do not have threaded studs. Instead, they have holes where you insert the lug bolt bolts through the wheel.

Lug bolts are harder to install, especially in larger vehicles with large wheels, because you need to support the weight of the wheel while you align the holes for the lug bolts.

On the other hand, when you install a wheel that uses wheel studs, you can hang the wheel on the wheel studs as you install the lug nuts.

However, even with this disadvantage, some European car manufacturers prefer to use lug bolts instead of lug nuts.

What Are The Types Of Lug Nuts?

There are different types of lug nuts. When buying an aftermarket wheel, you need to know if the wheel requires a specific type of lug nut.

The primary purpose of a lug nut is to keep the wheel on the car. Its secondary purpose is to prevent it from moving around in its position.

Most of the lug nut types below are exclusive to specific aftermarket wheels. The first three on the list are the primary lug nut types that are common in stock wheels.

Most lug nuts have a specific depth, while some look like normal nuts with an opening on both ends. When buying lug nuts, it is also important to know how much the wheel studs protrude.

If this length does not match the lug nut, then the lug nut will not be able to secure the wheel.

For example, if you have a wheel stud that protrudes by an inch and you have a lug nut that has a depth of half an inch, then the lug nut will not reach the surface of the wheel to keep it in place.

Conical Lug Nuts

Conical lug nuts are the most common lug nuts that you will find. They are also known as acorn lug nuts because their seat (the bottom of the lug nut that touches the wheel) is like the bottom of an acorn.

A conical lug nut’s tip tapers inward at a 60-degree angle. A conical lug nut is also the best fit for wheels that have a conical hole.

Some conical lug nuts have 45-degree angles, but these are mostly for Circle Track and NASCAR race wheels only.

The conical shape of the tip allows the nut to center itself on the wheel’s hole as you tighten it. This makes it very easy to work with and center, which contributes to its popularity.

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Spherical Lug Nuts

Spherical lug nuts are also known as ball seat lug nuts. As the name suggests, the seat of this type of lug nut is spherical in shape.

From a distance, it looks like a conical lug nut because the round taper is not too obvious. Additionally, wear and tear will eventually make it look more like a conical lug nut. The head of this type of lug nut also looks the same as a conical lug nut.

It is important to make a close inspection of the seat to determine if you have a spherical or a conical lug nut.

This type of lug nut is common in Honda, Audi, and Volkswagen car models.

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Flat Seat Lug Nuts

These lug nuts are also known as a level seat fasteners. They are the most normal looking of all the types of lug nuts because of their flat seats.

The seat of this type looks like a normal flat washer that is stuck at one end of the lug nut.

Additionally, some flat seat lug nuts are often open on both ends of the nut. The flat seat of the lug nut must fit into a flat indentation on the wheel. This is how a flat seat lug nut prevents precession. This is a lug nut that you use on specific wheels.

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Tuner Lug Nuts

A tuner lug nut is a specialty lug nut that is usable only on specific aftermarket wheels.

A tuner lug nut looks completely different from standard lug nuts. Its sides are smooth, which means that you cannot use a normal wrench to install or remove it from your wheel.

Instead of a hexagonal shape, the inside of a tuner lug nut has a special shape that matches the shape of a lug nut key.

One side of the key matches the shape and locks into it. The opposite end of the key has a hexagonal shape that you can use your socket on.

Keep in mind that this key is not unique. This means a tuner lug nut is not a theft deterrent. Thieves will need a copy of the key, and they will be able to remove the lug nut once they get one.

The seat of a tuner lug nut normally uses a conical lug nut.

Most aftermarket wheels for Asian cars like Honda or Acura have narrower holes for the lug nuts. This makes it impossible to use standard lug nuts with hexagonal shapes because they will not fit.

Losing the key will make it impossible to remove the lug nut until you get a replacement key.

The disadvantage of tuner lug nuts is that the top is open, which lets moisture in. The moisture will lead to rust on the stud and lug nut.

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Spline Drive Lug Nuts

Spline drive lug nuts are another type of specialty lug nut. Aftermarket wheel manufacturers that moved away from tuner lug nuts because of the possibility of rusting adopted the use of spline drive lug nuts.

A spline drive lug nut has the same slim profile as a tuner lug nut. However, instead of having a hole on top, a spline lug nut has grooves around its body. This allows the lug nut to maintain a slim profile and an enclosed top.

Spline drive lug nuts have the same conical seat as a tuner lug nut.

Similar to tuner lug nuts, this nut requires a key that has a spline pattern. However, just like the tuner lug nut, this is not unique. Thieves that get a copy of the key will be able to remove the lug nut.

Click here to see these spline lug nuts on Amazon.

Extended Thread Lug Nuts

This is a special version of a conical lug nut. Instead of a regular length for the thread, this version has a longer thread length.

To accommodate the longer thread, the lug nut has a protrusion below the seat. The protrusion allows for better wheel connection because of the better grip.

Another version of an extended thread lug nut doesn’t have a protrusion under the seat. Instead, the thread area between the seat and the top is longer.

This version provides the benefit of a better grip with your tool, making it easier to install and uninstall.

Mag Seat Lug Nuts

This is the extended thread version of the flat seat lug nuts.

Most versions of this type have an extension below the seat of the lug nut. The extension allows it to handle the extended thread of some wheel studs.

Similar to extended thread lug nuts, the additional length gives the lug nut a better grip to keep the wheel secure.

However, the design of the wheel should allow for the extension of the lug nut under the flat seat.

Open-Ended Lug Nuts

This type of lug nut is an umbrella type that describes a modification of any of the types above. An open-ended lug nut is open on both ends.

While this exposes the wheel stud to the risk of rusting, it allows the use of a single lug nut for wheels that use a spacer on track.

Double-Sided Lug Nuts

This is another lug nut modification.

All double-sided lug nuts are also open-ended lug nuts. However, not all open-ended lug nuts are double-sided lug nuts.

Double-sided lug nuts have seats on both sides. Thus, double-sided conical lug nuts have a conical seat on both sides.

The advantage of this lug nut is its convenience. If one seat is already starting to wear, you can use the other seat.

Conclusion

Lug nuts are important for keeping the wheels on your car secure. Various types of lug nuts are available. If you're buying aftermarket wheels, make sure you find out if they require a specific type of lug nut.

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