The Ultimate Guide to Bottom Bracket

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bottom bracket featured

A bottom bracket is the part of a bicycle where the cranks are attached to the frame. It is located at the bottom of the frame, hence the name. It is essentially a set of bearings that allow the cranks to rotate smoothly.

The bottom bracket plays an important role in transferring power from the pedals to the rear wheel. When you pedal, the force is transmitted from the pedals to the cranks, and then through the bottom bracket to the rear wheel. A well-functioning bottom bracket ensures that power is transferred efficiently, resulting in a smooth and comfortable ride.

And in the following content, we will walk you through every signle piece of information about this vital bicycle part: bottom bracket, from its types to its a number of standards, and more.

Bottom Bracket Types: Threaded or Press Fit

If we categorize the bottom brackets in the way of their installation, we can simply divide them into two different types, ie. the threaded bottom bracket and the press fit bottom bracket.

Threaded Bottom Bracket

threaded bottom bracket

The threaded bottom bracket is the older of the two types, and it’s still used in many bikes today. As the name suggests, this type of bottom bracket screws into the frame using threads. The bottom bracket shell of the frame has threads on the inside, and the bottom bracket cups have threads on the outside. The cups thread into the frame, and the spindle of the crankset passes through the bottom bracket.

One of the advantages of a threaded bottom bracket is that it’s relatively easy to install and remove. You only need a few tools, and you can do it yourself. Additionally, threaded bottom brackets have been around for a long time, so there’s a wealth of knowledge and experience out there when it comes to maintenance and repair.

Press Fit Bottom Bracket

press fit bottom bracket

The press fit bottom bracket is a newer design that’s become increasingly popular in recent years. Instead of screwing into the frame, this type of bottom bracket is pressed into place. The cups of the bottom bracket are made to fit tightly into the bottom bracket shell of the frame, using friction to hold them in place.

One of the advantages of a press fit bottom bracket is that it can be lighter than a threaded bottom bracket. Additionally, the design can allow for a wider bottom bracket shell, which can lead to a stiffer and more efficient frame. However, press fit bottom brackets can be more challenging to install and remove, and they may require special tools.

How Threaded Bottom Bracket and Press Fit Bottom Bracket Differ

Threaded and press fit bottom brackets differ in a few key ways. Threaded bottom brackets are generally easier to install and remove, while press fit bottom brackets can be lighter and stiffer. However, press fit bottom brackets can be more challenging to install and may require special tools.

When it comes to maintenance and repair, both types of bottom brackets require regular cleaning and lubrication. However, threaded bottom brackets may be easier to service, as there are more options for replacement parts and a wealth of knowledge and experience available.

Bottom Bracket Standard

1. BSA Threaded Bottom Bracket

BSA threaded bottom bracket is also known as the English threaded bottom bracket. We will learn about it by explaining its two unique mini standards, the ISO threaded internal and external bottom brackets.

ISO Threaded Internal Bottom Bracket

The ISO threaded internal bottom bracket is a standard with a threaded design that screws directly into the bottom bracket shell of the frame. It has a shell inner diameter of 34.8mm and a shell width of 68mm or 73mm. The bearing inner diameter is usually 24mm, but some models may have a 22mm diameter.

One of the benefits of this standard is its compatibility with a wide range of cranksets, including those with a 24mm spindle diameter, such as Shimano Hollowtech II, FSA MegaExo, and SRAM GXP. To install the bottom bracket, you’ll need a bottom bracket tool, which fits into the notches on the cups and allows you to tighten or loosen them.

ISO Threaded External Bottom Bracket

The ISO threaded external bottom bracket is another standard with a threaded design, but instead of screwing directly into the frame, it has cups that thread into the bottom bracket shell. The shell inner diameter is the same as the ISO threaded internal standard, at 34.8mm, but the shell width can vary from 68mm to 100mm.

The bearing inner diameter is also usually 24mm, but some models may have a 22mm or 30mm diameter. This standard is compatible with a wide range of cranksets, such as Shimano Hollowtech II, FSA MegaExo, SRAM GXP, and Campagnolo Ultra Torque.

To install this bottom bracket, you’ll need a bottom bracket tool that fits into the notches on the cups. Once you’ve threaded the cups into the bottom bracket shell, you’ll need to tighten them to the manufacturer’s recommended torque.

Differences between ISO Threaded Internal and External Bottom Brackets

The main difference between the ISO threaded internal and external bottom brackets is the way they attach to the frame. The ISO threaded internal standard screws directly into the bottom bracket shell, while the ISO threaded external standard has cups that thread into the shell.

Another difference is the shell width, which can range from 68mm to 100mm for the ISO threaded external standard, while the ISO threaded internal standard has a fixed shell width of 68mm or 73mm. The ISO threaded external standard is also compatible with a wider range of shell widths and cranksets.

Which Bottom Bracket is Better?

The choice between the ISO threaded internal and external bottom brackets ultimately depends on your bike’s frame and the crankset you plan to use. If your frame has a fixed shell width of 68mm or 73mm, the ISO threaded internal bottom bracket is the way to go. However, if your frame has a wider shell width or you plan to use a different crankset, the ISO threaded external bottom bracket may be a better fit.

2. Italian Bottom Bracket

The Italian bottom bracket is a type of bottom bracket that has a shell inner diameter of 70mm and a shell width of 36mm. The bearing inner diameter is usually 35mm, although there are some variations. This type of bottom bracket is compatible with Italian-threaded frames and cranksets.

The structure of the Italian bottom bracket is different from other types of bottom brackets. It consists of two cups that thread into the frame, and the bearings sit in the cups. The cups are usually made of aluminum, and the bearings can be either cartridge or loose ball.

When it comes to installation, the Italian bottom bracket can be a bit tricky. The cups need to be threaded into the frame in a specific way, and if they’re not installed correctly, you can damage your frame or bottom bracket. It’s best to have this type of bottom bracket installed by a professional.

Differences Between the Italian Bottom Bracket and BSA Threaded Bottom Bracket

The main difference between the Italian bottom bracket and the BSA threaded bottom bracket is their size. The Italian bottom bracket has a larger shell inner diameter and shell width than the BSA threaded bottom bracket. This means that the Italian bottom bracket is not compatible with BSA-threaded frames, and the BSA threaded bottom bracket is not compatible with Italian-threaded frames.

Another difference is the material of the cups. The Italian bottom bracket cups are usually made of aluminum, while the BSA threaded bottom bracket cups are usually made of steel. This can affect the weight of your bike, but the difference is usually negligible.

So, which one is better? It depends on your bike and your preferences. If you have an Italian-threaded frame, you’ll need an Italian bottom bracket. If you have a BSA-threaded frame, you’ll need a BSA threaded bottom bracket.

In terms of performance, there isn’t a significant difference between the two types of bottom brackets. Some cyclists prefer the Italian bottom bracket because it’s less common and adds a bit of flair to their bike. Others prefer the BSA threaded bottom bracket because it’s easier to install and more widely available.

3. T47

The T47 bottom bracket features a larger diameter than a traditional threaded bottom bracket, which provides a stiffer and more reliable interface between the frame and the crankset. This increased diameter also allows for larger bearings, which can improve durability and reduce friction.

It consists of an aluminum or titanium shell that is pressed into the frame. The shell has an inner diameter of 47mm, which is larger than the 37mm diameter of a traditional threaded bottom bracket. The bearings are then pressed into the shell, and the crankset spindle passes through the bearings. The bearings can either be pressed directly into the shell or into a cup that is then pressed into the shell.

The T47 bottom bracket is available in a variety of configurations, depending on the frame and crankset specifications. Here are some of the key specifications to consider:

  • Shell inner diameter: 47mm
  • Shell width: Typically 68mm or 73mm, but can vary depending on the frame
  • Bearing inner diameter: Typically 24mm or 30mm, depending on the crankset
  • Compatibility with cranksets: The T47 bottom bracket is compatible with most cranksets that use a 24mm or 30mm spindle diameter, including Shimano, SRAM, and Campagnolo
  • Installation: The T47 bottom bracket is installed by pressing the shell into the frame and then pressing the bearings into the shell. Some manufacturers recommend using a specific installation tool to ensure proper alignment and torque.

4. Colnago ThreadFit82.5

The Colnago ThreadFit82.5 bottom bracket is a type of bottom bracket standard used in high-end road bikes. It was first introduced by Colnago, an Italian bicycle manufacturer, and has since become a popular choice among cyclists. The ThreadFit82.5 is a press-fit bottom bracket that uses a threaded sleeve, making it easier to install and remove compared to other press-fit systems.

It consists of two threaded cups that screw into the frame’s bottom bracket shell, and a sleeve that connects the two cups. The cups are made of aluminum, while the sleeve is made of steel, making it durable and long-lasting.

The sleeve has two flanges that fit into the cups, ensuring that the bottom bracket stays securely in place. There are also two o-rings that sit between the cups and the sleeve, providing a tight seal to prevent water and dirt from entering the bottom bracket.

This bottom bracket standard has several features that make it stand out from other bottom bracket standards. Firstly, it has a shell inner diameter of 41mm, which is larger than most other bottom brackets. This allows for larger and stiffer bottom bracket axles, resulting in better power transfer and a more efficient ride.

Secondly, it has a shell width of 82.5mm, which is wider than most other bottom brackets. This extra width allows for a wider stance of the crank arms, resulting in better pedaling efficiency and stability.

Finally, the Colnago ThreadFit82.5 bottom bracket has a bearing inner diameter of 24mm, which is the same as most other bottom brackets. This means that it is compatible with most cranksets in the market.

Specifications of the Colnago ThreadFit82.5:

  • Shell inner diameter: 41mm
  • Shell width: 82.5mm
  • Bearing inner diameter: 24mm
  • Compatibility: Fits most cranksets in the market
  • Material: Aluminum cups, steel sleeve

5. Truvativ ISIS Overdrive

The Truvativ ISIS Overdrive Bottom Bracket is a standard that has been used on many mountain bikes and road bikes. Its design includes a spindle that connects the crank arms which is inserted through the frame’s bottom bracket shell. This allows the cranks to rotate smoothly, providing power to the bike’s drivetrain.

The Truvativ ISIS Overdrive Bottom Bracket has a few unique features that set it apart from other bottom brackets. One of these features is its oversized spindle, which measures 24mm in diameter. This larger size provides additional stiffness and durability, making it an excellent choice for riders who put their bikes through tough terrain.

It has an inner diameter of 68mm, which is the standard size for most road bikes and mountain bikes. The shell width is 113mm, which is the standard size for mountain bikes. The bearing inner diameter is 24mm, which is the same as the spindle diameter.

It is compatible with a wide range of cranksets. It is specifically designed to work with Truvativ’s own ISIS Drive cranksets, but it can also be used with other brands that use the ISIS Drive standard. The ISIS Drive standard is a splined interface that connects the crank arms to the spindle.

6. French

A French bottom bracket is a type of bottom bracket that was commonly used on bikes manufactured in France in the mid-20th century. This bottom bracket standard has a shell inner diameter of 35mm and a shell width of 68mm. The bearing inner diameter is typically 17mm, which is smaller than other bottom bracket standards.

One of the most unique features of a French bottom bracket is the threading. The cups have a 35mm x 1mm thread pitch, which is different from the standard ISO threading used on most bottom brackets. This means that you’ll need specific tools to install and remove a French bottom bracket.

Another feature of a French bottom bracket is the taper on the spindle. The spindle has a JIS taper, which means that it’s not compatible with modern cranksets that use an ISO or BB30 taper. If you’re looking to upgrade your crankset, you’ll need to find one that’s compatible with a JIS taper spindle.

As mentioned earlier, a French bottom bracket has a JIS taper spindle, which means that it’s not compatible with modern cranksets that use an ISO or BB30 taper. However, there are still some cranksets that are compatible with a French bottom bracket. Stronglight, TA Specialites, and Nervar are all brands that make cranksets that are designed to work with a French bottom bracket.

7. Chater-Lea

The Chater-Lea bottom bracket is a British standard that was first introduced in the early 1900s by the Chater-Lea company. It’s a threaded bottom bracket that uses a 1.37″ x 24 TPI thread, which is the same as the BSA (British Standard) standard. However, the Chater-Lea standard has a unique taper on the spindle, which means it’s not interchangeable with other bottom bracket standards.

The Chater-Lea bottom bracket has a distinctive design that sets it apart from other standards. It features a stepped shell with a smaller diameter on the non-drive side and a larger diameter on the drive side. This design allows for a wider bearing stance, which improves the stiffness and durability of the bottom bracket.

The Chater-Lea bottom bracket also has a unique spindle taper. It uses a 1:10 taper, which is shallower than the 2-degree taper used by other standards. This taper provides a more controlled fit between the spindle and crank arm, which improves power transfer and reduces wear and tear.

The Chater-Lea bottom bracket has a shell inner diameter of 1.37″ and a shell width of 68mm or 73mm. The bearing inner diameter is 35mm, which is larger than the 30mm used by some other standards. This larger diameter provides a wider bearing stance, which improves stiffness and durability.

The Chater-Lea bottom bracket is compatible with Chater-Lea cranksets, which are no longer in production. However, it may be possible to use other cranksets with the Chater-Lea bottom bracket if they have a compatible spindle taper.

To install a Chater-Lea bottom bracket, you’ll need a special tool called a Chater-Lea bottom bracket spanner. This tool is used to tighten the bottom bracket cups into the frame. The cups are threaded onto the frame and tightened against each other to secure the bottom bracket in place.

8. Whitworth

The Whitworth bottom bracket is a British standard that was commonly used in the mid-twentieth century. It features a threaded shell that is 1.37 inches in diameter, and a width of either 68mm or 73mm. The threads on the shell are cut to a Whitworth standard, which is different from the more common ISO threading used today.

The Whitworth bottom bracket consists of a drive-side cup, a non-drive side cup, and a spindle that runs through the middle. The cups screw into the frame’s threaded bottom bracket shell, while the spindle connects the two arms of the crankset.

The drive-side cup is typically right-hand threaded, while the non-drive side cup is left-hand threaded. This means that you’ll need to turn the cups in opposite directions to tighten or loosen them. It’s important to note that the threading on a Whitworth bottom bracket is different from ISO threading, so you’ll need specific tools to work on this type of bottom bracket.

The Whitworth bottom bracket has a shell inner diameter of 1.37 inches, which is smaller than the 1.370 x 24 tpi threading used for ISO bottom brackets. The shell width can be either 68mm or 73mm, although the latter is less common. The spindle typically has a diameter of 5/8 inch, or 15.875mm.

When it comes to compatibility with cranksets, the Whitworth bottom bracket is designed to work with cottered cranks. These types of cranks have a tapered square spindle that fits into a matching hole in the crank arm. If you have a cottered crankset, you can use a Whitworth bottom bracket to connect it to your bike frame.

9. O.P.C. Ashtabula

The O.P.C. Ashtabula bottom bracket is a one-piece design, meaning the spindle and crank arms are integrated into a single unit. This design provides increased strength and durability, making it ideal for BMX and freestyle riding. The bottom bracket shell is also wider than other standards, measuring 2-1/4 inches in diameter. This extra width helps to prevent flex and improves the overall stiffness of the bike’s frame.

The O.P.C. Ashtabula bottom bracket consists of a single piece of steel tubing that serves as both the spindle and the crank arms. The spindle is threaded on both ends, allowing it to be screwed into the bottom bracket shell. The crank arms are attached to the spindle with a pinch bolt, which tightens down on the flat section of the spindle to hold them in place.

If you’re looking to install an O.P.C. Ashtabula bottom bracket on your bike, there are a few specifications you’ll need to be aware of. The bottom bracket shell inner diameter is 51.3mm, and the shell width is 68mm. The bearing inner diameter is 51.3mm as well, and the overall spindle length is 169mm.

The O.P.C. Ashtabula bottom bracket is compatible with a variety of cranksets, including those from Schwinn, Huffy, and Murray. However, it is important to note that not all cranksets are compatible with all bottom bracket standards, so it’s important to do your research before making any upgrades to your bike.

10. O.P.C. Fauber

The O.P.C. Fauber bottom bracket is known for its durability and reliability. It’s designed to withstand the rigors of heavy use and rough terrain, making it an ideal choice for mountain bikers and other off-road cyclists. The bottom bracket features a strong, solid construction that helps to reduce flex and improve power transfer.

The O.P.C. Fauber bottom bracket consists of two main parts: the cartridge and the cups. The cartridge contains the bearings and spindle, while the cups are threaded into the bottom bracket shell of the bike frame. The spindle connects the cranks to the bearings, allowing for smooth rotation.

The O.P.C. Fauber bottom bracket is designed to fit frames with a 68mm or 73mm shell inner diameter and a shell width of 110mm. The bearing inner diameter is 24mm, making it compatible with most modern cranksets. The bottom bracket is designed to be easy to install, with the cups threading into the bottom bracket shell by hand.

The O.P.C. Fauber bottom bracket is compatible with a wide range of cranksets, including those from Shimano, SRAM, and Campagnolo. It’s designed to work with 24mm spindles, which are common on modern cranksets. However, it’s important to check the compatibility of your specific crankset before purchasing a bottom bracket.

11. Raleigh

The Raleigh bottom bracket has a unique structure that is different from other bottom brackets on the market. It features a shell inner diameter of 34mm and a shell width of 68mm. The bearing inner diameter is 24mm, and it uses sealed cartridge bearings.

One of the most significant features of the Raleigh bottom bracket is its durability. It is a reliable component that can last for years with proper maintenance. The sealed cartridge bearings offer excellent protection against dirt, water, and other contaminants that can cause damage to the bottom bracket.

The Raleigh bottom bracket is compatible with square taper cranksets. It is not compatible with other types of cranksets, such as Shimano Octalink or ISIS Drive. It is essential to ensure that you have the correct type of crankset before purchasing a Raleigh bottom bracket.

12. BB86 and BB92

The BB86 and BB92 standards are both designed for use with press-fit bottom brackets. The main difference between the two is the width of the shell. The BB86 has a shell width of 86mm, while the BB92 has a shell width of 92mm.

The BB86 and BB92 bottom brackets have a similar structure. They both consist of two cups that are pressed into the frame. The cups hold the bearings, which support the crankset.

Specifications of BB86 and BB92

  • Shell Inner Diameter: Both BB86 and BB92 have a shell inner diameter of 41mm.
  • Shell Width: The BB86 has a shell width of 86mm, while the BB92 has a shell width of 92mm.
  • Bearing Inner Diameter: The bearing inner diameter for both BB86 and BB92 is 24mm.
  • Compatibility with Cranksets: The BB86 and BB92 are compatible with most Shimano and SRAM cranksets.
  • Installation: Installing a BB86 or BB92 bottom bracket is relatively easy. First, clean the inside of the bottom bracket shell and apply a thin layer of grease. Then, press the cups into the frame using a headset press. Finally, install the crankset and adjust the bearings if necessary.

13. Trek BB90 and Trek BB95

The Trek BB90 and Trek BB95 bottom bracket standards are both designed to be lightweight and efficient. They use a press-fit design that eliminates the need for heavy metal cups, which reduces the weight of the bottom bracket and allows for a larger diameter spindle. The larger spindle diameter provides more space for bearings, which improves the stiffness and durability of the bottom bracket.

The Trek BB90 and Trek BB95 bottom bracket standards both use a press-fit design that allows the bottom bracket bearings to be pressed directly into the frame. The bearings are housed in composite or aluminum cups that are designed to fit snugly into the bottom bracket shell. The bottom bracket shell has an inner diameter of 37mm for the Trek BB90 and 37.5mm for the Trek BB95, and a width of 90mm or 95mm, depending on the specific bicycle model.

The Trek BB90 and Trek BB95 bottom bracket standards have some specific specifications that are important to consider when choosing a crankset. The bearing inner diameter for the Trek BB90 is 37mm, while the bearing inner diameter for the Trek BB95 is 37.5mm. These specifications are important to consider when choosing a crankset because they determine the compatibility of the bottom bracket with the crankset.

The Trek BB90 and Trek BB95 bottom bracket standards are compatible with a wide range of cranksets. However, it is important to choose a crankset that is designed to work with the specific bottom bracket standard. The Trek BB90 is compatible with Shimano, FSA, and Bontrager cranksets, while the Trek BB95 is compatible with SRAM, Truvativ, and Bontrager cranksets.

The installation of the Trek BB90 and Trek BB95 bottom bracket standards is relatively straightforward. The bearings are pressed directly into the frame, and the cups are then pressed into the bearings. The crankset is then installed onto the spindle and tightened to the appropriate torque specifications. It is important to follow the manufacturer’s instructions carefully when installing a bottom bracket to ensure that it is installed correctly and functions properly.

14. Look BB95

The Look BB95 bottom bracket is a press-fit standard that was introduced by Look in 2009. It features a two-piece design, with the non-drive side cup being permanently attached to the frame. The drive-side cup can be removed, making it easy to service the bottom bracket.

The Look BB95 standard has a shell inner diameter of 37mm, which is larger than the standard BB30 standard. The shell width is 95mm, which is wider than the BB30 and narrower than the PF30. The bearing inner diameter is 24mm, which is the same as the Shimano Hollowtech II and other popular cranksets.

The Look BB95 is compatible with Look’s own Zed and Trilobe cranksets, as well as Shimano’s Hollowtech II and other cranksets with a 24mm spindle diameter. It is not compatible with SRAM cranks, which have a 22mm spindle diameter.

Installing the Look BB95 bottom bracket requires a special tool, which can be purchased from Look or a bike shop. The cups are pressed into the frame using the tool, making sure they are aligned properly. The bearings are then installed into the cups, and the crankset is fitted onto the spindle.

15. Wilier BB94

The Wilier BB94 bottom bracket features a unique design that includes a shell with an inner diameter of 41mm and a width of 86.5mm. The bottom bracket is designed for use with press-fit bearings, which are pressed into the frame’s bottom bracket shell. The bearings used in the Wilier BB94 have an inner diameter of 24mm.

The Wilier BB94 bottom bracket is compatible with many different types of cranksets, including those made by Shimano and SRAM. When choosing a crankset for use with the Wilier BB94, it’s important to make sure that the crankset has a 24mm spindle diameter.

16. Specialized Alloy OSBB

Specialized Alloy OSBB stands for Oversized Bottom Bracket, a bottom bracket standard developed by Specialized Bicycle Components. It features a larger shell inner diameter of 46mm and a shell width of 68mm. This design provides a stiffer and more responsive ride by allowing for a larger diameter down tube and seat tube.

The Specialized Alloy OSBB has several features that make it stand out from other bottom bracket standards. These include:

  1. Oversized shell: The OSBB has a larger shell inner diameter of 46mm, which makes it stiffer and more robust.
  2. Lightweight: The OSBB is made of high-quality alloy, making it lightweight and durable.
  3. Compatibility: The OSBB is compatible with a wide range of cranksets, making it a versatile bottom bracket standard.
  4. Easy to install: Installing the OSBB is relatively easy, and you don’t need any special tools to get the job done.

Specifications of Specialized Alloy OSBB:

  • Shell inner diameter: 46mm
  • Shell width: 68mm
  • Bearing inner diameter: 30mm

The Specialized Alloy OSBB is compatible with a wide range of cranksets, including Shimano, SRAM, and Campagnolo. However, it’s essential to check the manufacturer’s specifications to ensure compatibility before purchasing a crankset.

17. Specialized Carbon OSBB

The Specialized Carbon OSBB bottom bracket standard is designed to offer a lightweight and stiff structure that maximizes power transfer in the bike. This bottom bracket standard is made of carbon fiber, which makes it strong and durable while keeping the weight low.

The Specialized Carbon OSBB bottom bracket standard has a shell inner diameter of 42mm and a shell width of 61mm. It’s compatible with a bearing inner diameter of 30mm and is designed to fit a wide range of cranksets, including those from Shimano, SRAM, and Campagnolo.

The Specialized Carbon OSBB bottom bracket standard is compatible with a wide range of cranksets, including those from Shimano, SRAM, and Campagnolo. It’s also compatible with different frame materials, including carbon fiber, aluminum, and steel.

Specialized Carbon OSBB vs Alloy OSBB: Which is better for your bike?

The main difference between the Carbon and Alloy OSBB bottom brackets is the frame material they are designed for. The Carbon OSBB is designed for carbon fiber frames, while the Alloy OSBB is designed for aluminum frames. This means that you cannot use an Alloy OSBB bottom bracket on a carbon fiber frame, and vice versa.

Another difference is the shell diameter and width. The Carbon OSBB has a larger diameter and width, which makes it stiffer and lighter. The Alloy OSBB has a smaller diameter and width, which makes it more compatible with standard BSA threaded bottom brackets.

The inner diameter of the bottom bracket is also different. The Carbon OSBB has an inner diameter of 30mm, while the Alloy OSBB has an inner diameter of 24mm. This means that the Carbon OSBB is compatible with most modern cranksets, while the Alloy OSBB is limited to Shimano and SRAM cranksets.

But which one is better? There is no clear winner when it comes to the Carbon vs. Alloy OSBB bottom brackets. It all depends on your bike frame and personal preferences.

If you have a carbon fiber frame, then the Carbon OSBB is the way to go. It’s lighter and stiffer, which will improve your bike’s performance. If you have an aluminum frame, then the Alloy OSBB is the better option. It’s more compatible with standard BSA threaded bottom brackets and is easier to find replacement parts for.

18. BB30

BB30 is a bottom bracket standard that was first introduced by Cannondale in 2000. It has become a popular choice among cyclists due to its light weight, stiffness, and efficiency. The BB30 system consists of a 42mm diameter shell with no threads, and bearings pressed directly into the frame. The shell width is 68mm for road bikes and 73mm for mountain bikes.

Features of BB30:

  • Shell inner diameter: 42mm
  • Shell width: 68mm for road bikes, 73mm for mountain bikes
  • Bearing inner diameter: 30mm
  • Crankset compatibility: BB30-specific cranksets or adapters for other cranksets
  • Installation: Press-fit bearings into the frame

Advantages of BB30:

  • Lightweight: BB30 bottom brackets are lighter than traditional threaded bottom brackets.
  • Stiffness: The larger diameter of the bottom bracket shell and spindle result in a stiffer and more efficient power transfer.
  • Wide crankset compatibility: BB30 bottom brackets are compatible with a wide range of cranksets, including BB30-specific cranksets and adapters for other cranksets.

Disadvantages of BB30:

  • Installation: Installing a BB30 bottom bracket requires special tools and expertise, which can be costly.
  • Noise: BB30 bottom brackets can be noisy due to the lack of threads holding the bearings in place.

BB30 vs Specialized OSBB: Which is Better?

When it comes to BB30 vs Specialized OSBB, both standards offer similar advantages and disadvantages. The key difference is in the shell diameter, with BB30 using a 42mm diameter shell and Specialized OSBB using a 61mm diameter shell. This means that Specialized OSBB bottom brackets are only compatible with Specialized OSBB-specific cranksets or adapters for other cranksets, while BB30 bottom brackets are compatible with a wider range of cranksets.

In terms of stiffness and efficiency, both standards are comparable and offer a noticeable improvement over traditional threaded bottom brackets. The choice between BB30 and Specialized OSBB ultimately comes down to personal preference and compatibility with your bike and crankset.

19. Cannondale BB30A and BB30-83 Ai

The BB30A and BB30-83 Ai bottom bracket standards share some similarities, but also have distinct differences. Both standards use a 30mm spindle and oversized bearings to reduce weight and increase stiffness. However, the BB30A has a larger shell inner diameter of 42mm compared to the standard BB30’s 68mm. This allows for a wider stance of the frame’s down tube and seat tube, improving stiffness and handling.

The BB30-83 Ai, on the other hand, features an asymmetric offset chainring that is shifted outward by 6mm. This allows for a more even spoke tension between the drive and non-drive sides of the wheel, resulting in a stronger and more stable rear wheel. The BB30-83 Ai also has a wider shell width of 83mm, which is necessary to accommodate the offset chainring.

The BB30A has a shell inner diameter of 42mm and a shell width of 73mm. It is compatible with any crankset designed for the BB30 standard, which includes most modern road and mountain bike cranksets. The BB30A is installed by pressing the bearings directly into the frame’s bottom bracket shell. Cannondale recommends using a headset press tool to ensure proper installation.

The BB30-83 Ai has a shell inner diameter of 46mm and a shell width of 83mm. It is only compatible with Cannondale’s Ai (Asymmetric Integration) cranksets, which are designed to work with the offset chainring. The BB30-83 Ai is installed using a special tool that threads into the bottom bracket cups and pulls them into the frame.

20. PF30

The PF30 bottom bracket standard is a type of bottom bracket that was designed to improve upon the BB30 standard. It was introduced by Cannondale in 2007 and has since been adopted by many other bike manufacturers. The “PF” in PF30 stands for “PressFit,” which means that the bearings are pressed into the frame rather than being threaded in like in a traditional bottom bracket.

One of the key features of the PF30 bottom bracket is its larger shell inner diameter of 46mm, as compared to the 42mm diameter of the BB30. This allows for a larger diameter of the spindle, which increases stiffness and reduces flex. The shell width of the PF30 bottom bracket is 68mm for road bikes and 73mm for mountain bikes. The bearing inner diameter of the PF30 bottom bracket is 30mm, which is the same as the BB30.

The PF30 bottom bracket is compatible with a wide range of cranksets, including those from SRAM, FSA, and Shimano. However, it is important to note that not all cranks are compatible with the PF30 bottom bracket. Make sure to check the manufacturer’s specifications before purchasing a new crankset.

Differences between PF30 and BB30

The main difference between the PF30 and BB30 bottom brackets is the way that the bearings are installed. In a BB30 bottom bracket, the bearings are pressed directly into the frame, while in a PF30 bottom bracket, the bearings are pressed into cups that are then installed into the frame. This makes the PF30 bottom bracket slightly heavier than the BB30, but it also makes it more durable.

Another difference between the two bottom brackets is the shell inner diameter. As mentioned earlier, the PF30 has a larger shell inner diameter than the BB30. This allows for a larger spindle diameter and increased stiffness.

When it comes to which bottom bracket is better, it really depends on your personal preferences and needs. The PF30 bottom bracket is more durable than the BB30, but it is also slightly heavier. On the other hand, the BB30 is lighter but may not be as durable in the long run.

Ultimately, the decision comes down to what type of riding you’ll be doing and what your priorities are. If you’re a competitive cyclist looking for the lightest possible setup, the BB30 might be the way to go. If you’re more concerned with durability and long-term performance, the PF30 might be a better choice.

21. BBRight (Press-Fit)

As a cycling enthusiast, you’re likely aware of the importance of a bottom bracket in your bike’s overall performance. That’s why it’s crucial to understand the different types of bottom bracket standards available on the market. In this article, we’ll take an in-depth look at the BBRight (press-fit) bottom bracket standard.

The BBRight (press-fit) bottom bracket was developed by Cervelo in collaboration with FSA. It was designed to improve stiffness, reduce weight, and increase durability. Here are some of its key features:

  • Shell Inner Diameter: 42mm
  • Shell Width: 79mm
  • Bearing Inner Diameter: 30mm
  • Bearing Type: Press-fit
  • Crankset Compatibility: BBRight (press-fit) cranksets

The BBRight (press-fit) bottom bracket has a wider shell than the standard bottom brackets, which provides more space for the bearing to fit. The larger diameter of the BBRight (press-fit) bottom bracket axle also increases stiffness and reduces weight. The bottom bracket is pressed into the frame, which eliminates the need for threads.

The BBRight (press-fit) bottom bracket is compatible with BBRight (press-fit) cranksets, which have a 30mm spindle diameter. Some popular brands that offer BBRight (press-fit) cranksets include FSA, Rotor, and Praxis.

Advantages of BBRight (Press-Fit) Bottom Bracket

The BBRight (press-fit) bottom bracket offers several advantages over the traditional bottom bracket standards. Some of the benefits include:

  • Increased stiffness and durability due to the wider shell and larger diameter axle
  • Reduced weight due to the elimination of threads
  • Improved power transfer due to the increased stiffness
  • Reduced maintenance due to the press-fit design

22. BBRight (Direct-Fit)

The BBRight (Direct-Fit) bottom bracket standard was developed by Cervelo as an alternative to other bottom bracket standards. It features a wider bottom bracket shell than traditional bottom brackets, which allows for better power transfer and stiffness. The bottom bracket bearings are pressed directly into the frame, eliminating the need for external cups.

The BBRight (Direct-Fit) bottom bracket standard has a shell inner diameter of 46mm and a shell width of 79mm. The bearing inner diameter is 24mm, which is the same as a Shimano Hollowtech II bottom bracket. This means that BBRight (Direct-Fit) bottom brackets are compatible with most Shimano Hollowtech II cranksets.

Difference between Press-Fit and Direct-Fit

There are two main types of bottom brackets: press-fit and direct-fit. Press-fit bottom brackets use external cups that are pressed into the frame, while direct-fit bottom brackets have the bearings pressed directly into the frame.

One advantage of press-fit bottom brackets is that they can be easier to install and remove than direct-fit bottom brackets. However, they may be more prone to creaking and require more maintenance. Direct-fit bottom brackets, on the other hand, can provide better power transfer and stiffness, but may be more difficult to install and remove.

23. BB386EVO

BB386EVO is a bottom bracket standard that was introduced by FSA (Full Speed Ahead) in 2011. It is an evolution of the BB30 standard, which was developed by Cannondale. The BB386EVO standard aims to combine the best features of BB30 and press-fit bottom brackets, resulting in a system that is lightweight, stiff, and durable.

The BB386EVO bottom bracket standard is known for its excellent features that make it a preferred choice for many cyclists. Here are some of its most notable features:

  • Lightweight: BB386EVO is designed to be lightweight, thanks to its large spindle diameter and thin-wall bearings. This results in a system that is up to 100 grams lighter than other bottom bracket standards.
  • Stiff: BB386EVO features a wide bottom bracket shell (86.5mm) that provides a larger surface area for the down tube to attach to, resulting in a stiffer frame.
  • Durable: The BB386EVO bottom bracket standard uses oversized bearings that are designed to last longer and require less maintenance.

The BB386EVO bottom bracket standard has a unique structure that sets it apart from other bottom bracket standards. Here’s a breakdown of its structure:

  • Shell inner diameter: BB386EVO has a shell inner diameter of 46mm, which is larger than other bottom bracket standards like BB30 (42mm) and BSA (34.8mm).
  • Shell width: The BB386EVO bottom bracket shell is 86.5mm wide, which is wider than BB30 (68mm) or BSA (68/73mm).
  • Bearing inner diameter: The BB386EVO bottom bracket uses oversized bearings with a 30mm inner diameter, which is the same as the BB30 standard.

One of the advantages of the BB386EVO bottom bracket standard is its compatibility with a wide range of cranksets. Here are some of the compatible cranksets:

  • FSA K-Force Light BB386EVO crankset
  • SRAM Red BB386EVO crankset
  • Shimano Dura-Ace BB386EVO crankset
  • Campagnolo Record BB386EVO crankset

24. BB392EVO

BB392EVO is a bottom bracket standard developed by Praxis Works, a company that specializes in drivetrain components. The standard was introduced in 2013 as a replacement for the BB30 bottom bracket standard, which was widely used in the cycling industry. BB392EVO is a press-fit bottom bracket that is designed to fit a 392mm wide bottom bracket shell with a 30mm spindle.

BB392EVO comes with several features that make it a popular choice among cyclists. The bottom bracket is stiffer, stronger, and more durable than other bottom bracket standards. It is also compatible with a wide range of cranksets, including Shimano, SRAM, and Campagnolo. The bottom bracket is available in a variety of colors, allowing riders to customize their bikes according to their preferences.

BB392EVO has a two-piece design that consists of a drive-side cup and a non-drive-side cup. The cups are pressed into the bottom bracket shell and held in place by a snap ring. The drive-side cup has a built-in spacer that allows the bottom bracket to fit frames with either a 68mm or 73mm shell width. The non-drive-side cup has a standard 42mm diameter, which is compatible with most cranksets.

BB392EVO has a shell inner diameter of 46mm and a shell width of 86.5mm. The bearing inner diameter is 30mm, which is compatible with cranksets that have a 30mm spindle. The bottom bracket is compatible with frames that have a 392mm wide bottom bracket shell. The bottom bracket weighs approximately 97g, making it one of the lightest press-fit bottom brackets available.

25. Spanish

The Spanish bottom bracket standard is a type of bottom bracket that is commonly used in BMX bikes. It is known for its durability and stiffness, which makes it ideal for BMX riding.

The Spanish bottom bracket standard consists of a spindle, two bearings, and two bearing cups. The spindle has a diameter of 19mm, which is smaller than the 22mm diameter used in other bottom bracket standards.

The bearings are pressed into the bearing cups, which are then threaded into the bottom bracket shell of the frame. The bearing cups have an inner diameter of 37mm and a shell width of 68mm.

The Spanish bottom bracket standard has a shell inner diameter of 37mm and a shell width of 68mm. The bearing inner diameter is also 19mm, which means it is only compatible with cranks that have a 19mm spindle diameter.

The Spanish bottom bracket standard is only compatible with cranks that have a 19mm spindle diameter, which is smaller than the 22mm diameter used in other bottom bracket standards. This means that you need to make sure that the cranks you choose are compatible with the Spanish BMX bottom bracket standard before you buy them.

Why There Are so Many Bottom Bracket Standards

If you are a cycling enthusiast like me, you might have wondered why there are so many bottom bracket standards. I mean, come on, wouldn’t it just be easier if there was only one standard for all bikes? But the reality is that there are good reasons why there are so many bottom bracket standards, and it’s not just to make our lives harder.

The bicycle industry is constantly evolving, and this is especially true when it comes to bottom bracket standards. Over the years, we have seen numerous bottom bracket standards, each with its own unique design and specifications. For example, some of the most common bottom bracket standards include BSA, BB30, PF30, BB86/92, and BB386EVO. But why are there so many standards? Well, the answer is simple: each standard is designed to meet specific requirements and needs.

One of the main reasons why there are so many bottom bracket standards is that different types of bikes require different standards. For example, road bikes, mountain bikes, and track bikes all have different bottom bracket needs. Road bikes, for instance, require a narrower bottom bracket to maintain the bike’s aerodynamics. On the other hand, mountain bikes require a wider bottom bracket to provide more clearance for the larger tires. So, if we were to unify the bottom bracket standard, it would not be possible to meet the specific needs of each type of bike.

Another reason why there are so many bottom bracket standards is advancements in technology. As technology evolves, so do the materials and designs used to create bike components. For example, carbon fiber frames require a different bottom bracket standard than aluminum frames. As such, manufacturers must create new bottom bracket standards to accommodate these advancements.

Competition among manufacturers is also a driving factor behind the many bottom bracket standards. Each manufacturer wants to create a unique selling point for their bikes, and having a unique bottom bracket standard is one way to do that. While this can make things confusing for consumers, it also drives innovation and keeps the industry moving forward.

While it might seem like unifying the bottom bracket standard would make things easier, it’s not the best solution. As we mentioned earlier, different types of bikes require different bottom bracket standards. Unifying the standard would mean compromising on the specific needs of each type of bike. Additionally, unifying the standard would take time and money, and it’s unlikely that all manufacturers would agree on a single standard.

Bottom Bracket Installation

1. Threaded Bottom Bracket Installation

If your bike has a threaded bottom bracket shell, installing a new bottom bracket is relatively simple. First, remove the old bottom bracket by using a bottom bracket tool. Then, grease the threads of the new bottom bracket and insert it into the shell. Tighten the bottom bracket cups with a bottom bracket tool, making sure they are snug but not too tight.

2. Press-Fit Bottom Bracket Installation

Press-fit bottom brackets are becoming more popular in modern bikes. To install a press-fit bottom bracket, first, remove the old bottom bracket by using a bottom bracket tool. Then, clean the bottom bracket shell and insert the new bottom bracket cups. Use a bearing press tool to press the bearings into the cups until they are flush with the frame. Finally, install the crankset and tighten the bolts to the manufacturer’s torque specifications.

Beside, please remember that a poorly maintained or damaged bottom bracket can affect the performance and safety of your bike. If the bearings are worn out or damaged, it can cause the cranks to wobble, making it difficult to pedal. This can also lead to the cranks seizing up, which can be dangerous if you are cycling at high speeds. So the skils of how to maintain and replace (when necessary) a bootm bracket have to be put into your pocket.

Maintaining a Bottom Bracket

Regular maintenance is essential to keep your bottom bracket functioning properly. Here are some tips to help you maintain your bottom bracket:

  1. Clean and lubricate: Regularly clean and lubricate the bottom bracket to prevent dirt and grime from affecting its performance.
  1. Tighten bolts: Check the bolts that hold the bottom bracket in place and make sure they are tightened properly.
  1. Replace worn out parts: If you notice any signs of wear and tear, such as cracks, rust, or grinding sounds, it is time to replace the bottom bracket.
  1. Seek professional help: If you are not confident in maintaining your bottom bracket, seek the help of a professional bike mechanic.

When to Replace a Bottom Bracket

The first thing you need to know is how to recognize when your bottom bracket is worn out. Here are some common signs:

  • Grinding or clicking noise when pedaling
  • Resistance or difficulty pedaling
  • Play or looseness in the cranks
  • Uneven or rough pedaling
  • Uneven wear on the chainrings and cogs

If you notice any of these signs, it’s likely that your bottom bracket needs replacing. However, it’s always best to have a professional bike mechanic inspect your bottom bracket to confirm the diagnosis.

As a general rule, most bottom brackets last anywhere from 2,000 to 5,000 miles. However, if you’re an aggressive rider who likes to tackle tough terrain or frequently rides in wet or muddy conditions, your bottom bracket may wear out more quickly.

Another factor to consider is the type of bottom bracket you have. There are several types, including square taper, external threaded, press-fit, and more. Each type has a different lifespan, so it’s important to check your bike’s manufacturer’s recommendations for when to replace your bottom bracket.

While there’s no surefire way to prevent your bottom bracket from wearing out, there are a few things you can do to extend its lifespan:

  • Keep your bike clean and well-maintained. Regularly clean and lubricate your chain and other moving parts to reduce wear and tear on your bottom bracket.
  • Avoid riding in wet or muddy conditions. Water and dirt can damage the bearings in your bottom bracket, causing it to wear out more quickly.
  • Inspect your bottom bracket regularly. Check for any signs of wear or damage, such as cracks or rust, and have a professional bike mechanic inspect it at least once a year.
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AUTHOR

Randy Joycelyn

Randy is the founder and editor of Cycling Soigneur. He has been passionate about cycling since he was a kid. He has been riding bikes for over 10 years. Cycling has just become a part of life.

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