Lug Nuts are not created equal
First things first before we talk about lug nuts, let’s cover the wheel stud. They are the threaded bolts (or studs) that protrude through the holes in your wheels onto which you would thread your lug nuts. Most vehicles have either 4 or 5 wheel studs per wheel, however, some trucks, vans or SUVs can have up to 8 per wheel.
Lug nuts are designed to ‘stretch’ a certain amount when torqued to their factory-specified level. This stretch allows the nuts to make a strong mechanical connection to the threads on the lug. (more about torquing and Retorquing later)
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.
Here’s a rundown of the most common lug nut types:
Types of Lug Nuts
There are actually a variety of different lug nuts and lug bolts out there. Each of the nine different types have their own distinguishing features. Many of these you’ll rarely encounter outside of a busy commercial garage.
#1 – Hex Nut
The hex nut is a very common type of lug nut. It features a hex shaped head that threads onto the wheel stud to secure the wheel in place.
Hex nuts are typically made of steel and chrome plated but you can also find them in lightweight materials such as aluminum (and anodized in different colors) or titanium.-
#2 – Conical Seat
Conical lug nuts (aka: acorn lug nuts) are very common lug nut type. The seat tapers inward at (usually) a 60 degree angle.
These cone shaped lug nuts are designed to fit a cone shaped hole. They are in most cases very easy to work with and center.
#3 – Ball Seat
Instead of being cone shaped, the seat on a ball lug nut is rounded or spherical. While not quite as common as conical lugs, ball seat lug nuts can be found on certain Honda, Audi, and Volkswagen vehicles.
The heads look almost identical to conical lug nuts so it may be hard to see which is which if they are installed.
#4 – Flat Seat
As the name suggests, the seat is flat and resembles a washer. Out of all the different types of lug nuts, flat seated ones are probably the most frustrating and difficult to work with. The problem is that centering them can be very tricky since they have a small barrel that goes into the lughole.
If not centered perfectly, the stem can catch so it seems like the lug nut is tightened when it actually isn’t. Since the flat surface has more surface area than others, they are more prone to getting stuck and can be much harder to remove.
#5 – Extended Thread
Similar to a standard conical lug nut, an extended thread (ET) lug nut adds the benefit of a longer thread. This is helpful in cases where the length of wheel studs and mounting surface of wheels simply doesn’t allow enough thread engagement when using regular lug nuts.
The longer thread length allows for better engagement to keep the wheels more securely attached.
#6 – Mag Seat
This is another type of extended thread lug, this time with a washer seat. It’s used in similar situations where a longer thread is necessary but instead of a conical, tapered bottom, they have a flat seat (sometimes with a washer, sometimes without).
They are called mag seat lug nuts because at one time, they were made out of magnesium.
#7 – Tuner Style
Many types of aftermarket wheels, especially for Hondas, Acuras, and other Asian tuner cars, are designed with smaller diameter holes for lug nuts. Standard acorn lugs will not fit so narrower tuner style lug nuts are needed.
To tighten or loosen these conical seat tuner lugs, a special tuning key is also needed which fits right over the lug. A normal socket then goes on top of the tuning key just like any other lug nut. This key is included when you purchase a set of tuner lug nuts but can also be purchased separately if the key is lost or your car didn’t come with one.
Because tuner style lug nuts are open in the center (to accept the tuning key), air and moisture can get to the studs and threads and cause corrosion. Because of this, tuner style lug nuts aren’t commonly used anymore and the spline drive style (below) is a much better alternative.
#8 – Spline Drive
Like tuner style lug nuts, this unique, small diameter lug has a conical seat and uses a special key. The difference is that instead of an opening in the middle, spline drive lug nuts have narrow grooves on the top and sides of the lug nut to accept the low profile key. They don’t have the same problem with possible corrosion.
Keep in mind that the pattern on spline drive (and tuner style) lug nuts is not unique so don’t assume you can use either as a theft deterrent. Respective replacement keys can easily be purchased by anyone form a local auto parts store or online.
#9 – Lug Bolt
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
For the lug nut to be correct it’s must be comprised of 5 things:
1) Thread Size
2) Thread Pitch
3) Seat Type
4) Length/Dimensions
5) Finish/Color
Thread Size:
You can easily identify your thread size and pitch with a simple thread pitch gauge available at any automotive store, or you can simply take one of your lug nuts to your local automotive store and spin it onto the bolts they have on hand. The thread size or thread diameter is the measurement taken across the outside diameter of your wheel stud threads measured in either standard (7/16″, 1/2″, etc.) or metric (12mm, 14mm, etc.) dimensions. The most common thread sizes are 10mm, 12mm, 14mm, 7/16″, 1/2″, 9/16″, 5/8″. You can find most factory stud sizes in your vehicle owner’s manual or you can use our online guide.
Thread Pitch:
The thread pitch is the measurement of either threads per inch for non-metric studs or the distance in millimeters between the threads for metric applications. This tool will help identify the proper thread pitch that was on the vehicle from the factory. If the vehicle has been modified, you will need to verify the thread pitch.
Seat Type:
The seat type refers to the area where the lug nut actually makes contact with the wheel surface. The most common types are either an acorn/tapered seat, a mag seat (which features a flat seating surface with a separate seating washer) or a ball seat which is common for Honda and Acura models.
Length/Dimensions:
It is critical that you confirm the dimensions of your lug nut or wheel lock to ensure a proper fit for both safety and appearance. This includes the outside diameter, overall length and for Mag style nuts/locks you must also determine the proper shank diameter and shank depth.
Finish/Color:
Our lug nuts and locks are available in a wide variety of finishes and colors including chrome plated, black chrome, stainless steel, zinc, yellow chromate, silver, red, blue and more.
Lug Nut FAQs
Are Lug Nuts Universal?The short answer is no. A common mistake a car owner can make is to assume all lug nuts are the same. As with any other type of fastener, lug nuts (or lug bolts) have some variation which are often preferred by one manufacturer or another. Thus, the vehicle you own plays a role in which lug nuts you have installed. Are Lug Nuts all the Same Size?This is perhaps the biggest misconception outside of all lug nuts having the same shape. In fact, there are several different sizes and thread pitches. Getting these wrong can damage the wheel, as will using the wrong type of seat. What About This Pitch Thing?Thread pitch is the measurement of either how many threads appear per inch (in SAE) or distance between the threads in millimeters (metric). For example, a 12mm x 1.25 lug nut size will have tighter threads than a 12mm x 1.75 size. What Are the Most Common Lug Nut Sizes?Here are the most common lug nut sizes in use today. The first number is the thread size (diameter) and the second number is the pitch (amount of threads).
Two other things to remember; 1) Do not put oil or lubricant on the threads of either the stud or lugs nuts/bolts, and 2) Re-torque the lug nuts/bolts after 50 miles NOTE: Most lugs use a right-handed thread, but there are exceptions, denoted by a “L” or “LHT” stamped on the side of the nut. Be very careful not to mix these up into your regular lug nuts. You can find the thread size (AKA thread diameter) by following one of a few methods:
What Are Common Lug Nut Socket Sizes?Socket sizes are another common issue you’ll encounter, and the required socket size can be just as manufacturer-specific as the nuts themselves. Regardless of whether you’re using a torque wrench, lug wrench, impact wrench, or standard ratchet, picking the right size of socket is important. You’re most likely to only need to use one of a small range, including: 17mm, 19mm (or 3/4″), 21mm (or 13/16”), 22mm (or 7/8”), or 23mm. |
** Minimum Thread Engagement for Wheel Nuts
Lug nuts, lug bolts, and wheel locks should always be tightened to the recommended torque specifications found in your vehicle’s owner’s manual. Safe and proper installation requires using the correct tools and procedures. This will prevent over-tightening the wheel fasteners, stripping the fastener threads, and stretching the studs.
The thickness of a wheel can differ from original equipment wheels to aftermarket wheels. For that reason, it’s critical to verify that the wheel nuts or lug nuts will properly engage the threads. General consensus is engagement must equal the thread diameter so M12x1.5 needs 12mm of engagement, M14x1.25 needs 14mm of engagement and so on. So if 1 turn of the nut equals 1.5mm, then for our M12x1.5 studs we need a minimum of 8 turns.
Refer to the chart below to determine the number of turns, or the depth of engagement, typical for your stud or bolt size.
Bolt/Stud Size | Number of Turns |
M14x2.0 | 7 |
M14x1.5 | 9.5 |
M14x1.25 | 11 |
M12x1.75 | 7 |
M12x1.5 | 8 |
M12x1.25 | 9.5 |
1/2″-20 | 10 |
5/16″-18 | 6 |
7/16″-20 | 8.5 |
9/16″-18 | 10 |
