Bottom Bracket Bearings

Bottom bracket bearings allow your cranks to spin smoothly and efficiently. They fit inside the bottom bracket shell, the frame part that connects the seat tube, down tube, and chainstays. The bottom bracket shell can have different sizes and shapes depending on the type of bike and frame.

Different types of bottom bracket bearings

There are two main types of bottom bracket bearings: threaded and press-fit. Threaded bottom brackets have cups with cartridge bearings that screw into the frame. They are easy to install and maintain but can creak if not tightened properly. Press-fit bottom brackets have bearings pressed into cups or shells that fit into the frame. They are lighter and stiffer than threaded ones but can be harder to remove and replace.

The size and shape of your bottom bracket bearings depend on your crankset. Different cranksets have different spindle diameters and lengths that require compatible bottom brackets. Some common standards for cranksets are BSA (British Standard), BB30 (30mm spindle), PF30 (press-fit 30mm spindle), BB86/92 (86/92mm wide press-fit) and BB386EVO (86mm wide 30mm spindle).

To find out what kind of bottom bracket bearings you need for your bike, you can measure your frame's bottom bracket shell width and diameter and your crankset's spindle diameter and length. You can also check your bike's specifications online or consult a professional mechanic.

Bottom bracket bearings are essential for a smooth and efficient ride. They should be regularly checked for wear and tear, cleaned and lubricated to prevent corrosion and friction. If you notice any signs of damage or noise from your bottom bracket bearings, you should replace them immediately.