Lug Nut Types and Sizes

Lug Nuts

What are lug nuts and what is the difference between the lug nut types and sizes? Lug nuts, or lug bolts, are the hardware that is used to secure your wheel and tire assembly to your vehicle. Having the correct lug nut for your vehicle is very important to ensure that your wheel is safely and securely installed.

Each of these lug nuts can also have an "open-end" on the top of the lug nut, not dipicted in these examples. An open-end lug nut allows the stud to extend through the lug nut, simply removing the need for the cap on the end. In most cases. an open-end lug nut is used when the lug nuts are covered by the wheels center cap or hubcap.

Here’s a rundown of the most common lug nut types:

Lug Nut Types

Conical or Tapered Seat

Conical or Tapered Seat
cone-shaped lug seat

Spherical or Ball Seat

Spherical or Ball Seat
rounded lug seat

Mag Seat

Mag Seat
extended thread area
and a flat washer seat

Flat Seat

Flat Seat
flat, washer-like seat

Extended Thread (ET)

Extended Thread (ET)
conical shaped seat
with an extended thread
for more thread engagement

Tuner Style

Tuner Style
small diameter using
a special key on the
outside end with a conical seat

Small Diameter Spline Drive

Small Diameter Spline Drive
small diameter using a
special key on the spline grooves
with a conical seat

Lug Bolts

Lug Bolts - lug nuts with the stud attached and used on vehicles that have a flat rotor with no studs

Lug bolts are simply lug nuts that have the stud attached to them. They are typically seen on European vehicles, such as Audi, BMW, Mercedes and VW. When installing lug bolts, it is important to ensure that they are not too long for the wheel which can cause movement issues. Check that the lug bolts are not too long by spinning the wheel while it’s off the ground, making sure it has 360-degrees of motion.

Lug Nut Sizes

Lug nut sizes have a specific thread pitch, which is determined by the vehicle specifications. It is important to match up the lug nut to your specific vehicle. Here are the most common lug nut sizes:

  • 10mm X 1.25
  • 12mm X 1.25
  • 12mm X 1.50
  • 12mm X 1.75
  • 14mm X 1.25
  • 14mm X 1.5
  • 14mm X 2.0
  • 7/16" X 20
  • 1/2" X 20
  • 9/16" X 18

Note: Most lug nuts are right-hand threaded. Left-hand threaded lug nuts are not very common and would have a "L" or "LHT" stamped on the side of the lug nut.

It is crucial that the lug nut seat and the wheel lug seat match. If the lug nut seat type does not match the wheel seat type, it is possible that the lug nut could damage the wheel. It is also likely that a mismatched lug nut and wheel could potentially cause the lug nut to loosen and the wheel to become unsecure to the vehicle.

What lug nuts do I need for aftermarket wheels?

Aftermarket wheels, not the original equipment (OE) factory wheels, are designed to upgrade the appearance and even performance of your vehicle. If you get aftermarket wheels, make sure you have lug nuts that will fit properly. Most OE lug nuts are not designed to fit aftermarket wheels. That’s why we recommend purchasing a wheel installation kit to ensure the lug nuts match your wheels.

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What is lug nut thread engagement?

Thread engagement refers to how much contact your lug nut has with the stud, or how many complete turns before it is tight. For your safety, proper thread engagement must be met.

If proper thread engagement cannot be met with a standard lug nut, an extended thread (ET) lug nut may be necessary. When installing an ET lug nut, you must ensure that the lug holes in the wheel are wide enough to accommodate the ET lug nut. If the lug nut isn’t long enough to engage the threads, the wheel will not be secured properly and is NOT recommended.

What is lug nut torque?

It is very important to make sure the lug nut is torqued to the right specifications, in foot pounds. If overtightened, both the lug nut and the stud can be fatigued, possibly leading to failure. To learn about the proper lug nut torque settings for your vehicle, check out our wheel torque chart.

Why is the outside diameter of lug nuts important?

It’s important to be aware of the lug head diameter.

Some lug nuts have a hex nut shape that is designed for a range of regular sockets. Others have a spline-like shape that requires a special key. There are also locking lug nuts, which require a serial-numbered lug key for install/removal.

If you purchase aftermarket lug nuts, make sure that you have the hardware to be able to install/remove your lug nuts. It may be a good idea to invest in a universal tire iron.

Small diameter lug nuts are commonly used on aftermarket wheels and will require an adapter for install/removal. This adapter may not be the same size as the OE lug head diameter.

Replacing OE Lug Nuts

When do you need to replace your OE lug nuts? Some OE lug nuts will last many years without ever needing to be replaced, but others may not be so lucky. Some OE lug nuts have a tin cap that covers the lug nut and can come loose or begin to swell over time. In both instances, although remaining secure to your wheel, will be a problem if you need to remove them. The swollen cap will make the diameter slightly larger than your lug wrench and they will not be easily removed. At the same time, if the tin cap falls off completely, this makes the lug nut slightly smaller than the lug wrench and also will not fit properly and often times causes the lug wrench to slip or strip out the end of the lug nut. Here are some examples to help illustrate this:

Swollen Cap:

Tin Cap Missing:

It is recommended to replace either of these types of issues with an aftermarket lug nut. Aftermarket lug nuts are a solid, one-piece lug nut. They do not have any caps and are made of the strongest grade materials to withstand the highest temperatures without compromising their shape.

Aftermarket Lug Nut:

Have any more questions about lug nuts? Please, give us a call or stop by any of our America's Tire locations and we'll get you taken care of!

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