Road bike bottom bracket

The threaded BSA is screwed into the bottom bracket shell, whilst the press-fit is pressed in without threads. The threaded BSA (British Standard) is the most widespread historical standard: reliable, removable by hand with the right tool, quiet and requiring no special tools for assembly. It remains compatible with almost all cranksets on the market via adapters. Pressfit (PF30, BB86, BB92) emerged with carbon frames to reduce frame weight and allow for larger axles. Major drawback: frequent creaking noises caused by the movement of the cups within the bottom bracket shell, which are difficult to eliminate.

Yes, it is one of the most common causes of noise on a road bike. Bottom bracket creaking is linked to three main causes: cups that are not tightened properly (BSA) or not seated correctly (press-fit), worn bearings with play, or contamination (water, sand) getting between the cup and the frame. To diagnose the problem: press down hard on the pedals whilst standing up on a climb; if the creaking intensifies, the bottom bracket is likely to be the cause. Solution: remove, clean, apply grease to the threads (BSA) or a light threadlocker to the press-fit cups, then reassemble to the correct torque.

Every 10,000 to 20,000 km for an entry-level or mid-range bottom bracket; ceramic versions last 30,000 km or more. Signs of wear: noticeable lateral play in the cranks (axle moving from left to right), resistance when pedalling, creaking or a degraded rolling noise. Standard threaded bottom brackets (Shimano, FSA, Token) cost €10 to €40 and are easy to replace. Ceramic bearing bottom brackets (CeramicSpeed, Kogel, Enduro) cost €150 to €400 but offer significantly longer life and a measurable slight reduction in rolling resistance.

Not directly, as the axle standards are different. Shimano uses the Hollowtech II axle (24 mm) with specific bottom brackets. SRAM has long used the GXP axle (24/22 mm, asymmetrical), which is incompatible with Shimano bottom brackets. Since 2020, SRAM has been using its DUB standard (29 mm) on high-end groupsets. Adapters are available (Token, Wheels Manufacturing) to fit a SRAM DUB crankset onto a BSA or PF30 bottom bracket designed for Shimano, and vice versa. Always check compatibility with the frame and the crankset axle before making a purchase.

The T47 is a 47 mm threaded standard that combines the advantages of BSA (threaded, no creaking) and press-fit (large diameter, wide axle).It is threaded like the BSA, which guarantees a quiet, easily removable fit, but with a larger diameter (47 mm compared to 34 mm for the BSA), allowing for bottom bracket axles of 30 mm or more. T47 is gaining popularity on gravel bikes and some high-end road frames. It is considered by many to be the best compromise currently available, avoiding the creaking associated with press-fit systems whilst accommodating modern, larger axles.

You will need the correct bottom bracket tool (Shimano TL-BB12, Park Tool BBT-9, etc.) and a precise torque setting. Procedure: remove the cranks using the appropriate puller, insert the BB wrench into the bottom bracket grooves, unscrew anti-clockwise for the right side (drivetrain side, left-hand thread) and clockwise for the left side (right-hand thread). When reassembling, apply grease to the threads, screw in by hand, then tighten to the recommended torque (35 to 50 Nm depending on the manufacturer). Insufficient tightening causes creaking; excessive tightening can damage the carbon frame’s threading.

For a cyclist covering more than 8,000 km/year with performance goals, yes; for leisure use, the value for money is debatable. Ceramic bottom brackets (CeramicSpeed, Kogel) reduce rolling resistance by 2 to 5 watts compared to standard steel bottom brackets, according to the manufacturer’s tests. Over a 3-hour threshold-intensity ride, this represents a saving of 6 to 15 Wh, which is a measurable but not decisive gain. Their lifespan (30,000 km+) makes them gradually more cost-effective compared to steel bottom brackets, which need replacing every 15,000 km. However, they are more susceptible to water and contaminants if the seals are not perfect.

Campagnolo Ultra Torque bottom brackets are exclusive to the brand’s Ultra Torque system and are incompatible with Shimano and SRAM. Campagnolo’s Ultra Torque system divides the axle into two parts, each integrated into a crank arm. The bottom bracket simply houses two outer bearings that are assembled at the centre. This elegant design is entirely proprietary. Adapters from third-party brands (Token, Rotor) sometimes allow an Ultra Torque crankset to be fitted to frames with a PF86 bottom bracket, but with compatibility compromises that must be checked on a case-by-case basis.

Post-replacement creaking is often due to insufficient tightening torque or a lack of grease on the threads. For a new BSA bottom bracket, always apply grease to the threads (Finish Line, Muc-Off) before tightening: this makes it easier to tighten to the target torque and prevents the bottom bracket from seizing in the frame threads due to thermal expansion. For a new press-fit bottom bracket, ensure the cups are fully seated (using a specific installation tool) and apply light-duty Loctite threadlocker (blue) to the plastic/carbon interface. After assembly, a 50 km break-in period may be necessary for the components to settle.