Your hub assembly plays an indispensable role for your brake and wheel end. Know what to look for when you are in the market for hub assemblies.
Hub assemblies go by many names in the heavy-duty industry. Hub Assembly. Wheel hub unit. Wheel hub bearing unit. No matter what you call it, the hub assembly plays an integral role in your wheel end system.
The hub assembly essentially enables your vehicle’s wheels to turn freely which is crucial for handling and safety. The exterior/tone ring is attached to or cast into your hub which is crucial for the proper operation of your anti-lock brakes (ABS) and traction control system (TCS) when equipped on your vehicle.
No matter if you are driving a semi-truck, pulling a commercial trailer, hauling debris on a construction site or working in the fields farming, you won’t go very far if your hub assembly isn’t working properly. In this article, we’ll break down the importance of your hub assembly. As we do, we’ll answer some of your top questions, which may include:
What does the hub assembly do?
What are the main components of a hub assembly?
What causes wheel hub failure?
What are the types of hubs to look for when buying?
What are the best hub assembly brands?
How Does A Hub Assembly Work?
The hub assembly connects your application’s tires to your axle and houses the wheel bearings, that keep the wheels spinning freely. The assembly ensures a smooth ride for you and your load.
It’s positioned between the brake drums/discs and the axle.
Outside the hub assembly: Your wheels are attached to the studs of the hub assembly.
On the axle side: The hub assembly is slid onto a spindle, and inner and outer roller bearings are positioned between the axle hub and spindle, ensuring smooth rotation from the wheel to the axle.
On the brake drum/disc side: attachment is determined whether you have disc brakes or drum brakes, and from there, inboard or outboard drums.
What Are The Main Components Of A Hub Assembly?
As you probably know or have figured out, the wheel hub consists of various, moving pieces when installed.
Inside the hub assembly
Wheel Bearings – While there are many precision manufactured components that comprise the entire hub assembly, the vital wheel bearing is housed here. Brush up on your Wheel Bearing know-how by reading: Five Things You Need to Know about Wheel Bearings. This particular piece is critical to your truck’s performance: smoothness of the ride, to fuel efficiency, to the integrity of your brake and wheel end system. There are inner and outer bearings on either side of the hub.
Seals: This part is responsible for keeping out contaminants like dirt, water, salt, debris, metal flakes and other tiny particles that wreak havoc on your bearings as well as containing the lubricants for the wheel end. Check out Wheelco’s Seals & Bearings Quick Guide to see what our team recommends if you need to replace yours.
Lubrication: With moving parts, it’s important to reduce heat and friction. Depending on what type of application you are driving will determine the type of lubricant.
Grease cap/dust cap: Pressed over the outer edge of the hub assembly, this component is used on the outside of the hub to keep debris out and lubrication in.
O-Rings: In some models, O-rings are used as a last defense against grease/oil that may be leaking out of the hub assembly most commonly used with ConMet hub assemblies.
Bearing snap ring: Some models use a metallic, rigid band keeps the roller bearing assembly in position during installation most commonly used with ConMet hub assemblies.
In oil bath applications, such as larger trailers, a bolt-on the cap is normally used.
Why Do Hub Assemblies Go Bad?
Just like any product, weather plays a major role in the longevity of your parts. Corrosion from the weather can wear down parts. Road treatment chemicals and salts also factor in for wheel hub corroding. Wheel hubs can be installed improperly and can be dangerous to driver safety. However, driving technique factors in as well as hitting potholes, curb checks and vehicle collisions can cause major damage to your hubs. Nevertheless, like any component, increasing frequency of use and wear and tear often mean you’ll need replacing the part sooner than later.
Wheelco Quick Tip: Service intervals are recommended every half a million miles, which is approximately every second brake job.