How to Remove and Install Cartridge Bearings Properly

Cartridge bearings are common in modern wheel hubs, bottom brackets, and some headsets because they are durable, sealed, and easy to replace when worn. However, removing and installing them incorrectly can damage the hub shell, deform the bearing seats, or shorten the life of the new bearings. With the right tools and a careful approach, you can service cartridge bearings safely and efficiently.

Begin by removing the axle and end caps from the hub. Most modern hubs use press-fit sealed bearings, so you will need a bearing puller or a drift punch designed for this purpose. Never strike the bearing directly with a hammer, and never push through the inner race unless the bearing is already going into the trash—pressing on the wrong surface is the fastest way to damage hub components.

To remove the bearings, insert the puller tool so it catches the inside of the bearing’s inner race. Tighten the puller until the bearing begins moving outward. Apply slow, steady pressure. If you are using a drift punch, position it at the edge of the inner race and tap gently around the circle to push the bearing out evenly. Once the first bearing is removed, the axle (if still inside) should slide out easily, giving access to the second bearing.

Clean the inside of the hub shell thoroughly. Dirt or corrosion inside the bearing seat will prevent the new bearing from sitting flush. Use a lint-free cloth and isopropyl alcohol. If you see deep scratches or oval deformation in the seat, the hub may require professional repair.

Before installing new bearings, check the bearing code (such as 6803, 6902, 6903). Each hub model requires a specific size. Lightly grease the bearing seats—not to lubricate the bearing itself, but to prevent corrosion and ease future removal.

Use a proper bearing press with drifts that match the outer race of the bearing. Never press using the inner race—this forces the balls into the raceways and damages the bearing before it is even installed. Align the bearing with the seat, hold the press straight, and turn the handle slowly. You should feel smooth resistance as the bearing moves into place. Stop when the bearing bottoms out fully and evenly against the seat.

Repeat the installation on the opposite side. For hubs with floating axles, ensure the axle is centered before pressing the second bearing. Misalignment can create binding, leading to premature wear.

Reinstall the axle and end caps and perform a spin test. The hub should feel smooth, silent, and free of side play. If you feel grinding or tightness, one of the bearings may be misaligned or pushed in too far. In that case, remove and reinstall again—forcing a misaligned bearing will damage both hub and bearing.

Below is a simple table you can copy directly into Word for documenting the process:

Cartridge Bearing Service Record

Step / Component	Status	Notes
Old bearings removed	Yes / No
Hub shell cleaned	Yes / No
Bearing code used		e.g., 6902
Drifts matched to outer race	Yes / No
Left bearing installed	Yes / No	Fully seated?
Right bearing installed	Yes / No	Fully seated?
Axle reinstalled	Yes / No
Final spin test	Smooth / Rough