Guide to bottom brackets

A bottom bracket, also called bottom bracket, forms the connection between the frame and the crankset of your bicycle. So choosing the right bottom bracket depends on two factors: the type of frame and the type of crankset you use.

1 (frame type) + 2 (crankset type) = 3 (bottom bracket)

To determine frame type and crank type, you only need to measure a few dimensions. You can then use these dimensions as a filter in our shop.

Pressfit frames have a bottom bracket shell with a smooth inside into which the bottom bracket is pressed.

The type of a pressfit frame is always determined by a combination of 2 dimensions, the width of the bottom bracket shell and the inner diameter of the bottom bracket shell. If you have both of these dimensions, you will always be able to reduce a frame to one specific frame type.

Tip: We always recommend measuring both dimensions when multiple inner diameters of the bottom bracket shell are possible in combination with a given bottom bracket width.

The BB30 frame standard was originally introduced by Cannondale, but was later used by other manufacturers. Bearings with an outer diameter of 42 and inner diameter of 30mm are pressed directly into the bottom bracket shell to be used with a BB30/PF30 crank. By using adapters, it is also possible to use other crank types in combination with a BB30 frame.

The BB30A frame standard was originally introduced by Cannondale and is a variant of the BB30 frame standard. The BB30A's bottom bracket shell is 5 mm wider than the BB30 standard and asymmetrical on the non-drive side of the frame.

The BB86-BB92 frame standard was originally developed by Shimano and grew to become the most widely used pressfit frame standard in the bicycle industry. BB86-92 is used by brands such as Giant, Canyon, BMC, Cube and others.

The BB89 frame standard is a variant of the BB86-BB92 frame standard and is used exclusively on (older) types of MTB.

The BB386 frame standard combines the width of a BB86 road frame (86.5mm) with a larger 46mm diameter bottom bracket housing.

The BB90-BB95 bottom bracket standard was developed by Trek. Bearings with an outer diameter of 37 mm were pressed directly into the bottom bracket shell for use with a Shimano or SRAM GXP crank. Due to the limited diameter of the bottom bracket housing, these frames can only be used with 24 mm cranks.

The PF30 (Pressfit30) frame standard was originally introduced by Cannondale as a variant of the BB30 frame standard. Bearings with an outer diameter of 42mm and an inner diameter of 30mm are installed in a cup after which the cup is pressed into the bottom bracket shell. This frame standard was developed to be used in combination with a BB30/PF30 crank, but by using adapters it is also possible to use other crank types in combination with a PF30 frame.

The PF30A frame standard was originally introduced by Cannondale and is a variant of the PF30 frame standard. The frame housing of the PF30A is 5 mm wider than the PF30 standard and asymmetrical on the non-drive side of the frame.

The OSBB (Oversized Bottom Bracket) frame standard was developed by Specialized and was only used in Specialized carbon frames for a short period of time.

Beware of the term 'OSBB'. The term OSBB (Oversized Bottom Bracket) is once incorrectly applied to pressfit frames that you can often trace by measurement to another standard such as BB30 or Pressfit30.

The BBright bottom bracket standard was developed by Cervélo and focuses on optimizing power transfer and improving frame stiffness. The BBright standard differs from traditional BB30 - PF30 bottom bracket systems by a wider asymmetric design, where the drive-side of the bottom bracket has the same width as traditional BB30 and PF30 frames (68 mm), but the non-drive-side is 11 mm wider resulting in a total bottom bracket shell width of 79 mm.

A distinction is made between a direct fit BBright42 and a pressfit BBright46 frame standard, the difference being in the inner diameter of the bottom bracket shell.

Threaded frames have a bottom bracket housing with an internal thread in which the bottom bracket screws directly into place.

To determine these frame types, it is sufficient to measure the width of the bottom bracket shell. Only if the width is 68 mm, the inside diameter of the thread must be measured. If it is 34 mm then you have a BSA frame, if it is 47 mm then you have a T47 frame.

The BSA frame standard is the most commonly used thread standard for attaching bottom brackets in bicycle frames and is marked 1x37" x 24T. The cups have right-hand thread (normal thread) on the non-drive side of the frame and a left-hand thread on the drive side of the frame.

The Italian frame standard is a threaded standard for attaching bottom brackets in bicycle frames and is characterized by the designation 36 x 24T. This frame standard is mainly used by Italian frame builders. Both cups have right-hand thread (normal thread).

The T45 frame stand is a threaded standard for attaching bottom brackets in bicycle frames. This frame standard is mainly used on a number of Colnago brand models. The cups of a T45 bottom bracket have right-hand thread (normal thread) on the non-drive side of the frame and a left-hand thread on the drive side of the frame.

The T47 frame stand is a threaded standard for attaching bottom brackets in bicycle frames. This frame standard is a modern bottom bracket standard that combines the larger 46 mm diameter of an oversized pressfit system with the reliability of a threaded system. With a width of 68 mm (road) and 73 mm (MTB), the bearings are mounted in cups outside the frame (hence outboard). The cups have right-hand thread (normal thread) on the non-drive side of the frame and a left-hand thread on the drive side of the frame.

The T47-Trek frame stand is a threaded standard for attaching bottom brackets in bicycle frames. This frame standard is a variation of the T47 frame standard. The bearings are mounted in cups inside the bottom bracket shell (hence inboard). The cups have right-hand thread (normal thread) on the non-drive side of the frame and a left-hand thread on the drive side of the frame.

The T47A frame stand is a threaded standard for attaching bottom brackets in bicycle frames. This frame standard is an assymetric variation of the T47 frame standard. The cups have right-hand thread (normal thread) on the non-drive side of the frame and a left-hand thread on the drive side of the frame.

Determining the crank type of your bike can be done by measuring the axle thickness, but also by identifying the data mentioned on the crank (brand, type).

All Shimano cranks (ROAD and MTB) have an axle diameter of 24 mm.

Check out the possibilities with Shimano

All SRAM GXP cranks (ROAD and MTB) have an axle diameter of 24 mm with a narrowing on the non-drive side to 22 mm (hence 24-22).

Check out the possibilities with Sram GXP

All SRAM DUB cranks (ROAD and MTB) have an axle diameter of 29 mm.

Check out the possibilities with Sram DUB

All modern 30 mm cranks are type 386. The axle thickness of these cranks is 30 mm. Some well-known brands of 386-type cranks are Rotor, FSA386 and Raceface.

Check out the options with 386 - Rotor30 - FSA386 - Raceface30

Is an older crank standard that you will therefore find mainly on older bikes. These cranks have an axle thickness of 30 mm but these axles are shorter than those of 386 cranks. These cranks can only be used with BB30 or PF30 frames.

Check out the possibilities with BB30/PF30

All PRAXIS M30 cranks (ROAD and MTB) have an axle thickness of 30 mm with a narrowing on the non-drive side to 28 mm (hence 30-28).

Check out the possibilities with Praxis M30

Campagnola Ultra Torque cranks have an axle diameter of 25 mm.

Check out the possibilities with Campagnolo Ultra Torque

CEMA Interlock bottom brackets are bottom brackets for pressfit frames. The two halves of the bottom bracket are connected inside the frame by means of a thread. This interconnection ensures a strong whole and a perfect alignment of the bearings. Also, the cups will not be able to move separately from each other leading to a stable and creak-free solution. We will always use this interlock construction whenever possible.

Find out how to install an Interlock bracket here:

Easily find the right bottom bracket for your bike with our easy-to-read bottom bracket chart. This handy guide contains all the specifications and compatibility overviews of the different bottom brackets available. Whether you're looking for threaded or pressfit options, you'll quickly find the right combination of width, diameter and crank type. Use this tool to see exactly which solution fits your frame and crankset for optimal performance.

Download chart Shop chart pack

Choosing the right bottom bracket is critical to the performance of your bike. With this guide, you'll be well on your way to finding the perfect match for your needs. If you still have questions about this, don't hesitate to contact us. We're always ready to help!