Threaded bottom brackets

The main advantage of threaded bottom brackets is their reliability and easy assembly. They use threaded cups that screw into the frame and provide a secure and stable connection. This design makes the maintenance of the bottom bracket easier, as well as its replacement if necessary. Additionally, threaded bottom brackets are less prone to creaking and loosening compared to other types, such as pressfit hubs. There are several types of threaded bottom brackets available on the market, each with their own specifications and compatibility. Here are some of the most common thread types:

BSA (English/ISO) : The most used type of bottom bracket. It has a standard 34.8 mm x 24 TPI (threads per inch) thread and is compatible with most modern road and mountain bikes. BSA Threaded bottom bracket are available in a variety of lengths to accommodate a variety of cranksets and frame designs.
Italian: Italian threaded bottom bracket have a standard 36 mm x 24 TPI thread. They are used primarily in Italian-made frames and are less widespread compared to the BSA type. They require specific tools for installation and removal.
French: French threaded bottom bracket have a standard 35 mm x 25.4 TPI thread. They were commonly used in older French-made bikes, but are less common these days. Finding replacement French midfield formations can be challenging due to their limited availability.

Make sure the bottom bracket matches the thread standard of your frame and the cranks you want to use.

What specifics to consider when choosing a threaded bottom bracket?

When buying a threaded bottom bracket, consider the following parameters to achieve functionality and compatibility with your bike:

Width: Threaded bottom brackets come in different widths, which are determined by the width of the bike frame. Common bottom bracket widths are 68 mm and 73 mm for mountain bikes and 68 mm for road bikes or others. The bottom brackets are supplied with washers that are used to adjust the required width.
Thread diameter: Threaded bottom bracket have specific diameters that correspond to the thread standard used. For example, English/BSA threaded bottom brackets typically have a thread diameter of 1.37 inches (34.8 mm).
Crankset compatibility: Threaded bottom bracket are available in a variety of crankset compatibility designs. Common crankset standards include: square taper, ISIS, Octalink and external bearing systems such as Hollowtech II.
Material: Threaded bottom bracket are commonly made from aluminium or steel. Aluminium bottom bracket are lighter but can be less durable, while steel ones are generally more durable but heavier.

How often to service or replace the bottom bracket?

The frequency of service or replacement of the threaded bottom bracket can vary depending on various factors such as riding conditions, rider weight and maintenance procedures. However, as a general guideline, it is recommended that the threaded bottom bracket be serviced or inspected at least once a year or every 1,000 km. Regular maintenance includes disassembling the crank and checking the bearings for signs of wear, roughness, or float. If there are any problems, such as excessive wear or noise, the bottom bracket may need to be replaced. Also, if you notice any squeaks, clicks, or other unusual noises when pedalling, it's a good idea to have the bottom bracket checked and repaired sooner rather than later. Regular monitoring of the condition and timely resolution of any issues can help extend its life and ensure smooth and efficient pedalling.

What are the recommended brands or models of threaded bottom brackets?

There are several reputable brands that offer quality bottom brackets. Here are some recommended brands and models:

Shimano: Shimano is a well-known brand in the cycling industry and offers a range of threaded bottom brackets, including the Ultegra and Dura-Ace or Hollowtech series, which are known for their durability and smooth running.
SRAM: SRAM offers threaded bottom brackets as part of its GXP (Giga X Pipe) or DUB system. These bottom brackets are known for their reliability and are compatible with SRAM cranksets.
FSA (Full Speed Ahead): FSA offers a variety of threaded bottom brackets, including the MegaExo series, which are popular among road and mountain bikers for their smooth running and compatibility with FSA cranksets.

Do threaded bottom bracket have a reverse thread?

The common thread for threaded bottom brackets is called “English”. The left bowl has a right-hand thread that tightens clockwise and removes counter-clockwise. The bowl on the right side (at the drive) has a left-hand thread, which is tightened counter-clockwise and loosened clockwise.