Wheel Bolts Vs Wheel Nuts and How to Measure.

Wheel Nuts & bolts are essential components that keep a vehicle’s wheels securely in place while allowing for their removal when necessary. Let’s delve into some details:

Wheel bolts screw directly into the wheel hub, eliminating the need for wheel studs.
Wheel nuts thread into a wheel stud, which is semi- permanently fitted in the wheel hub.

If you regularly change your wheels or tyres on your vehicle, you'll be familiar with the fact that your wheels are held on by either wheel bolts or wheel nuts.

What's the difference?

Wheel Bolts Wheel Nuts

Let's start with the difference between a wheel bolt and a wheel nut. Visually it is very easy to distinguish a wheel bolt from a nut by its thread. If it has an external thread, it is a wheel bolt and if it has an internal thread, it is a wheel nut.

A wheel nut threads onto a wheel stud, which is seated semi-permanently in the wheel hub. A wheel bolt screws directly into the wheel hub eliminating the need for wheel studs.

Now that you know the difference between wheel nuts and wheel bolts let's look at the different seating types that are used.

Cone / Taper Seat

A cone or taper seat wheel nut/bolt features a cone-shaped seating area. The one commonly has a 60-degree angle; however, some less commonly use a 45-degree or 90-degree angle. The angle indicates the degree of separation between the two walls of the nut/bolt and the wheel seat.

Flat Seat

A flat seat can also be referred to as Shank nut. They feature a shank that extends under the head which is used to centre the wheel and provide extra thread engagement.

Radius Seat

A radius seat or ball seat has a rounded seating area. The radius of this rounded area varies and can be R12, R13 or R14 depending on your vehicle.

Ok, so we've now been through the different seating types, but to add more confusion you can get different styles of wheel nuts/bolts. But don't worry, we will go through them below.

Hex-Style

Hex-style wheel bolts/nuts are the most used style and what you can expect to be fitted to your vehicle from standard. They are hexagonal and range in size,17mm, 19mm and 21mm, although 22mm and 23mm are used in some applications.

Vari / Wobble Nut and Bolt

If you swap the wheels on your car, one of the things that needs to be considered, is the PCD. As you can see on the picture, this is the circumference of the center of the bolt holes. If this is out by more than a few millimetres then the wheels are not compatible. If it is only a few millimetres difference, you can fit the wheels, but will need what is called a Variable nut/bolt (also known as wobble nuts/bolts)

As you can see in the picture with the nut, they have a moving collar on the nut/bolt which allows 1-3mm lateral movement, meaning the different PCD’s can line up safely. Failure to use this style of nut/bolt where necessary can be very unsafe.

Tuner Nut / Bolt & Key

Tuner wheel bolts/nuts feature a slimmer head diameter which is typically 20mm or 23mm. There are alloy wheels that are designed to use this style, they are common with JDM / Japanese wheels. Tuner bolts/nuts require a key to tighten and loosen the fixing which is a internally star fitment.

Open Wheel Nuts

Open-ended wheel nuts are threaded the length of the nut and do not have a closed end. It will allow you to use the nut with longer wheel studs if you have fitted wheel spacers, without having to worry about running out of thread. Another benefit of open nuts is that they allow for more contact with the wheel stud.

Closed Wheel Nuts

Closed wheel nuts have a closed end meaning they can only be threaded onto the stud up to the closed end of the nut. Because of this closed nuts can have less contact with the wheel stud compared with open nuts. The benefit of closed nuts is that they protect the thread of the stud from the elements, preventing it from rusting. They are also popular as they are more aesthetically pleasing once fitted compared to open wheel nuts.