Bicycle bottom brackets

Bottom brackets are a key part of the bike's drivetrain and connect the crankset to the frame. They ensure smooth and efficient rotation of the cranks, thus enabling energy transfer. There are two common types of bottom brackets: pressfit and threaded.

Pressfit bottom brackets

In recent years, pressfit bottom brackets have become more and more popular. Instead of screwing into the threads of the frame, they are pressed directly into the hole. They usually have plastic or metal bowls that fit snugly into the frame.

Advantages of pressed bottom bracket

Weight: Pressfit bottom brackets are generally lighter than threaded bottom brackets, because they do not require heavy metal threaded cups.
Stiffness: Pressfit designs often provide wider mid-compound cups, allowing for a stiffer, more stable feel due to the direct connection to the frame and more efficient energy transfer.
Easy installation: Pressfit bottom brackets are easier to install and remove because they do not require threading.

Disadvantages of pressfit bottom brackets

Noise and creaking: Pressfit bottom brackets can be more prone to noise and creaking in the frame.
Precise installation: Proper installation of pressfit bottom brackets requires precise alignment with the frame and press tools to ensure a secure connection to the frame.
Compatibility: There are different standards for pressfit bottom brackets, and compatibility can vary between frames and individual bottom bracket designs.

Threaded bottom brackets:

Threaded bottom brackets have been the traditional standard for many years. They have threads that screw into the frame.

Advantages of threaded bottom brackets

Reliability: Threaded bottom brackets are known for their durability and reliability, being well-proven designs that have been used for a long time.
Wide compatibility: Threaded bottom brackets are widely compatible with a variety of frames and cranksets.
Easy maintenance: Threaded bottom brackets are easier to maintain and service because they are relatively easy to remove and replace.

Disadvantages of threaded bottom brackets

Weight: They are usually a bit heavier due to the metal threaded bowls.
Limited stiffness: Compared to wider pressfit designs, threaded bottom brackets may have slightly less stiffness.

Which is better - threaded or pressfit?

The choice between pressed and threaded bottom brackets depends on various factors such as frame compatibility, crankset compatibility, personal preference and maintenance requirements. There is no clear answer to the question of which is better, as it ultimately depends on specific needs.

How to replace threaded bottom bracket?

Follow these general steps to replace the bottom bracket:

Remove the cranks if necessary using a crank puller.
Unscrew the bowls of the bottom bracket using a BB tool.
Clean the centre of the frame and the thread.
Lubricate the threads and install a new threaded bottom bracket.
Reassemble the cranks and tighten the bolts to the required torque.

How to replace pressfit bottom bracket?

Follow these general steps to replace the bottom bracket:

Remove the cranks if necessary using a crank puller.
Use a bearing punching tool to knock out the old pressed-in bearings of the bottom bracket.
Clear the centre of the frame.
Apply lubricant and press in the new bottom bracket bearings using a press tool.
Reinstall the crankset and tighten the bolts.

These are simplified steps, and it is always recommended to refer to the manufacturer's specific instructions and seek professional assistance if necessary.