When it comes to replacing heavy duty wheel bearings, it’s important to know the differences between steel and aluminum hubs. So let’s chart the differences. Starting with steel hubs, you’ll notice that it’s a more forgiving material and you don’t need to be as careful compared to working with aluminum. It’s typically also easier to remove the race using a bearing puller without risking damage or gouging the surface of the hub. You’ll typically find steel hubs on drive and trailer axles.

Then there are aluminum hubs, which you’ll typically only find on the steer axles. They’re favored by OEMs because of the lighter weight compared to steel, which offers fleets opportunities for improved fuel efficiency. However, aluminum is a less forgiving, softer material that is more easily damaged or scratched when removing or installing bearings.

The preferred method of removing bearings from an aluminum hub is to weld a bead around the inside of the bearing race which shrinks the race (after cooling) and makes it easier to remove. This takes more time and adds extra steps and necessitates the use of more tools.

Here are a few more wheel bearing installation tips for aluminum hubs:

• When installing bearings, a damaged aluminum hub can cause issues with getting the race to seat properly, which causes misalignment. Misaligned bearings lead to uneven distribution of loads in the bearing, which lessens the life of the bearing and causes premature failure.
• Heating the aluminum hub can aid wheel bearing installation.
Cooling the race in a freezer will also ease with the installation.

Finally, it’s important to note that since the bearing and the aluminum hub are different materials, it is more common to have fretting damage which can occur when the race spins or creeps inside of the hub.

This technical tip was sponsored by Bower Heavy Duty Bearings by NTN.