Bike bottom brackets

Two families

The bottom bracket brings together the bearings on which the crank axle turns. There are two main types. The threaded bottom bracket, screwed into the frame, like the Shimano to English BSA standard, with widths of fifty-eight or seventy-three millimetres, is easy to maintain. The press-fit bottom bracket, force-fitted into the frame, is lighter and is used in many carbon frames, such as the Rotor, Gineyea, or THM models.

The pedalling parts

Pedalling parts are also available in different categories:

• Cranksets.
• Cranks.
• Chainrings.
• Pedals.
• Cleats.
• Stars.
• Accessories.

All parts are gathered on the pedalling page.

The axle diameter

The bottom bracket must match the axis of the crankset. Entry-level cranksets use a square axle, like the Shimano cartridge bottom bracket or Stronglight. Modern cranksets use a hollow axle of twenty-four millimetres, like the Shimano Hollowtech, or about twenty-nine millimetres, like the DUB standard from SRAM. Bearing manufacturers such as Black Bearing or Enduro offer adaptations between frames and axles.

Creaking and replacement

A worn bottom bracket shows up with a creak with every pedal stroke, lateral play in the cranks, or rough rotation. The bottom bracket or its bearings need replacing. The threaded bottom bracket can be removed with a specific tool; the press-fit requires a puller and a press. Stainless steel or ceramic bearings last longer. It's important to grease threads and housings during installation.

Good deals

Good bargains can also be found in the good deals, promotions, clearance, sales, Black Friday. The new products showcase the latest collections, and items shipped in 24h are prepared and dispatched within 24 hours. Key times of the year follow a stable order: Black Friday in late autumn, the end-of-year holidays, the winter sales, the French Days of spring, followed by the summer sales and the back-to-school season.

Frequently asked questions

Threaded or press-fit bottom bracket: how do I know which one is on my bike?

You check the sides of the bottom bracket: threaded cups on the outside indicate a threaded bottom bracket, bearings flush with the frame indicate a press-fit. The technical specifications of the frame confirm the standard.

Why does my crankset creak?

A creak often comes from a worn bottom bracket, loosely fitted or dry, but it can also originate from the pedals, chainring bolts, or the saddle. Start by greasing and tightening these parts; if the noise persists, replace the bottom bracket.

How do I choose a compatible bottom bracket for my crankset?

You need to match the frame standard, threaded or press-fit, and its width, to the diameter of the crankset axle, for example, twenty-four millimetres for Shimano Hollowtech. Adapter bottom brackets allow for certain combinations.

What is the English BSA thread?

The BSA is the most common threading standard, found on bottom brackets with widths of fifty-eight or seventy-three millimetres. The right side is threaded in reverse, so it doesn't loosen under pedalling effort.

Should I replace an old square axle bottom bracket?

The square axle bottom bracket, robust and simple, remains suitable for city and vintage bikes. It should be replaced with a model of the same axle length; switching to a hollow axle also requires changing the crankset.