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What Type Of Lug Nut Should I Use?

Which style lug nuts should I use with my wheels?  Many people have bought a set of wheels at a local swap meet, from a friend, or even an online auction and need lug nuts to install on their newly purchased rims.  Or they want to replace their current lugs to freshen up the look of their wheels.  Choosing the proper lug nut is critical.  Also there are some wheel retailers that do not include the lug nuts with the wheels and sell them separately.  At Wheelsforless we include at no charge the proper lugs for the wheels. Different type wheels use different lug nut types, and using the wrong type lug means the wheels will not be fastened properly and cause damage to the wheel, vehicle, or even injury if the wheel comes off the vehicle.

First you will need to determine the proper lug nut seat type.  Nearly all wheels have one of three lug nut seat types which are cone seat, mag with washer seat, and ball seat.  Thankfully today's wheels rarely use the old  mag and washer seat.  When aluminum wheels were originally introduced they used the mag and washer seat.  These wheels had a flat surface around the lug hole, and for the lug to seat and stay fastened properly a washer was  used to spread the contact surface of the lug nut.  This mag style seat type was proved not to be the best way to fasten a wheel.  They were difficult to install, and were susceptible to improper installation binding up in the lug holes and not fully fastening flat against the wheel.  Here is an drawing showing the mag and washer seat type.
Notice the flat surface around the lug hole, the shank of the lug that goes down into the inner lug hole, and the washer that ensures a flat contact to fasten the wheel.  If you have older wheels with this flat surface around the lug hole, you cannot use a conical or ball seat type lug.  If you do your wheels will not stay fastened and you are endangering your well being.

Most of today's wheels made for the U.S. are cone seat.  Cone seat wheels have a "beveled" or "conical" surface around the outer part of the lug hole.  This beveled edge is on a 60 degree angle.  This type of fitment uses a conical seat lug or what may also be referred to as an acorn lug.  This type of lug seat is easier to install, and does a better job of fastening the wheel.  And because of the beveled edge the wheel is centered when the  acorn lugs are tightened against the conical surface around the outer lug hole.  If you have a wheel with the conical surface around the outer lug hole then do not use washers with the acorn lugs or use either a ball seat or  mag and washer lug style.  Again if you do so you risk your wheels being damaged and coming completely off the vehicle.  Here is a drawing showing the cone seat type:
One important thing to consider when using an acorn style lug is to ensure you have enough thread engagement.  The rule of thumb is that the minimum thread engagement is equal to the width of the stud.  So if you have 1/2" studs you will need to have at least 1/2" of thread engagement.  If you aren't sure how much engagement you are getting with your acorn set up, there is an easy way to find out.  Put some chalk on the inside of your lug and then install your wheels with the chalked lugs.  Once installed securely, back off the lugs and then you should see chalk on the studs.  Simply measure the length of the chalk on the stud.  If it is equal to or more than the stud size, then you're good to go.  If not, you'll need to either change out your studs for a longer stud or you can use an "ET" lug.  "ET" stands for extended thread.  This lug type fits cone seat wheels, but has about .3" of extra shank to go inside the inner lug hole on a conical type wheel.  The extended thread lug nut still has the conical seat with the extra shank to get more thread engagement.  Again as with a standard acorn lug, do not use a washer with the extended thread lug nut.  Here is an image of the "ET" Lug or extended thread lug:
Also do not allow the acorn style lug to bottom out on the stud.  This will cause the clamping force of the lug not being applied to the wheel.  If this occurs you may need to look for longer acorn lugs or use an open acorn lug. Here is a picture of an open style acorn lug:
Many European vehicles use a ball seat lug type.  These wheels have a bowl around the outer lug hole instead of a 60 degree slope like the cone type lug hole.  These lugs have a rounded bottom to the lug and fit correctly in the bowl shape of the European style wheel.  Here is an drawing of the ball seat lug style:
Just because your wheels are going on a European car does not mean the wheels are ball seat.  Many aftermarket wheels made for the U.S. will have the conical 60 degeree lug hole even though they are made for European cars.

Another thing to consider is that some aftermarket or custom wheels have a very small opening for the lug hole. Standard acorn lugs may fit down in the hole, but there is not enough room to get a socket on the lug.  These wheels use a "spline" drive lug.  The lugs are smaller in outer diameter than a standard lug and require a special lug socket that comes with the lugs in order to install or remove the lugs.  This adapter is small enough to fit into the  tight space of the lug hole.  Here is an image of a spline drive lug and adapter:
The final thing that needs to be determined is the proper thread diameter.  This is not determined by the wheel style or lug type, but the year, make, and model of your vehicle.  Thread diameter is the diameter of the stud measured at the outer edges of the threads.  "Thread Pitch" for non-metric applications refers to the number of threads per inch, and for metric sizes it is the distance in millimeters between threads.  So if a lug size is referred to as 1/2"-20,  then the lug fits a stud with 1/2" diameter and uses 20 threads for one inch.  You can find most vehicle's stud size in the owner's manual of the vehicle or use an available application guide as a reference.

Some older Chrysler and Ford cars use left handed lugs on the right side of the vehicle.  These left handed lugs tighten by turning counter clockwise instead of clockwise.  In the '60's and even into the '70's some car and truck manufacturers thought that having the lug tighten counter clockwise would help ensure the lug from backing off on the passenger side of the car.  Wheelsforless has a lug pack with 10 left hand and 10 right hand 1/2" acorn lugs.


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