Cartridge bottom bracket replacement

Removing a cartridge bottom bracket can seem intimidating, but with the right tools and our experts’ guidance, it’s a task that you will be able to accomplish in your workshop.
In this article, we’ll discuss the advantages of sealed bottom brackets and provide a guide to changing them. So here it is, a step-by-step guide to help you remove and replace your bottom bracket.

cartridge bottom bracket

Advantages of a cartridge bottom bracket

Cyclists of all levels require a smooth and reliable riding experience, and the bottom bracket is an essential component in achieving this. Cartridge bottom brackets are a popular choice among cyclists, as they offer a number of benefits and are relatively low maintenance.

  • Ease of Maintenance: These types of bottom brackets are sealed units, meaning that they don’t require the same level of upkeep as traditional cup and cone bottom brackets. This makes them a great option for cyclists who don’t want to spend time and money on regular maintenance.
  • Durability: They are designed to withstand the rigors of regular use, making them much more durable than 3-piece bottom brackets. With proper installation and maintenance, they can last for years, providing reliable and consistent performance.
  • Smoother Performance: The design of sealed bearings helps to reduce friction, providing a smoother and more efficient pedaling experience. This can result in improved speed and power.

Cartridge bottom bracket durability

How Long Does a Cartridge Bottom Bracket Last?

The lifespan can vary depending on several factors such as the quality of components and frequency of use. On average, a well-maintained cartridge bottom bracket can last anywhere between 2 to 3 years. High-end models can last even longer, providing reliable performance for extended periods. However, it is important to regularly inspect your bottom bracket for signs of wear, such as creaking or looseness, to ensure that it continues to perform at its best.

Cartridge bottom bracket maintenance

Can You Service a Cartridge Bottom Bracket?

This type of bottom bracket unit is designed to be low maintenance, but it can eventually wear out. If this happens, the best way is to replace it as servicing of a cartridge bottom bracket is very limited. However, regular maintenance, such as removing and cleaning the unit can help to prolong its lifespan.

Can You Tighten The Loose Cartridge Bottom Bracket?

Sealed bottom brackets are designed as maintenance-free sealed units, so tightening them is not possible. If you experience any issues with your bottom bracket then it’s time to change it with a new one. Before you do that check which replacement you need. Our article here will guide you through different types of bottom brackets so you can find the right one for your bike.

Replacing a cartridge bottom bracket

Tools required

  • Crank extractor
  • 14mm socket spanner or a 8 mm allen key
  • 20 spline bottom bracket tool
  • Adjustable spanner
  • Flat head screwdriver
  • Long tube.
  • Big washer
  • Grease or anti-seize
  • Cloth or a paper towel


  • Put the bike in a stand or turn it upside down.
  • If you have front gears then move the chain to the lowest chainring.
  • Remove the chain from the crank so that it rests on the bottom bracket shell.
  • To get access to the bottom bracket you will first need to remove the cranks.
  • If you have crank dust caps then remove them with a flat-head screwdriver.
  • Using a 14mm socket spanner or 8mm allen key remove the crank bolts anticlockwise.
  • Before you screw the crank extractor into the crank make sure that the bolt part does not stick out of the nut part.
cartridge bottom bracket shell measurement
  • Now, using your hand, gently screw the crank extractor into the crank arm on the drive side. If the tool is not screwing in then don’t force it as you may damage the thread. Remove it and repeat the process until the tool sits in the threads properly.
  • Once the tool is in place use the adjustable spanner to tighten the nut part of the extractor.
  • Now screw the bolt part of the extractor with your hand all the way in.
  • Move the crank so that it points between 9 o’clock and 10 o’clock and place the adjustable spanner on the bolt part of the extractor so that it points to 2 o’clock. 
  • Hold the crank and screw the crank extractor clockwise until the crank comes out.
  • Remove the crank extractor from the right hand side crank and gently screw it into the crank arm on the non-drive side.
  • Repeat the crank removal process. Our article here will guide you through removal of different types of crank arms.
  • To make sure that you can get a correct replacement first measure the bottom bracket shell. Two most common lengths are 68mm and 73mm.
  • Now measure the axle length. Double check this measure as the axles differ from each other only by a few millimetres and it is important to get the exact replacement.
cartridge bottom bracket axle measurement

Removing a cartridge bottom bracket

Once the cranks are off it’s time to remove the bottom bracket.

  • Fit the 20 spline bottom bracket tool into the bottom bracket on the drive side.
  • If you have a big washer, place this on the tool and tighten it with a crank bolt. This will hold the tool in place.
cartridge bottom bracket 20 spline tool fitted on the drive side
  • Fit the adjustable spanner so that it points towards the handlebars.
  • Hold the frame with one hand and turn the adjustable spanner clockwise.
cartridge bottom bracket removal on the drive clockwise
  • If the spanner won’t budge then use a long tube. This will add to the leverage.
cartridge bottom bracket removal using a long tube to ad leverage
  • Once the bottom bracket is loose remove the bottom bracket with your hand.
cartridge bottom bracket unit removal
  • Undo the bottom bracket cup on the non-drive side anticlockwise and remove it from the shell.
cartridge bottom bracket cup unscrewing anticlockwise

Replacing a cartridge bottom bracket

  • Use a clean rag or cloth to clean the bottom bracket and the threads in the bottom bracket shell. This will help to ensure a smooth and easy installation of the new bottom bracket.
  • Apply a small amount of grease or anti-seize to the threads in the bottom bracket shell.
  • Fit the bottom bracket unit on the drive side. Screw it gently with your hand anticlockwise until it sits in the bottom bracket shell.
cartridge bottom bracket unit screwing in anticlockwise
  • Fit the 20 spine tool, washer, and crank bolt and by using an adjustable spanner, tighten the bottom bracket shell anticlockwise.
cartridge bottom bracket unit on drive side tightening anticlockwise
  • Remove the crank bolt and the washer.
  • Fit the bottom bracket cup on the non-drive side and tighten it remembering that it screws in clockwise.
cartridge bottom bracket cup on non drive side screwing in clockwise
  • Refit the cranks. If you’re not sure how to do this we have a great article here that will guide you through this task.
  • Fit the chain on the chainring.
  • If required refit the crank dust caps.


Healthy and well-maintained cartridge bottom brackets offer a number of benefits to cyclists, including ease of maintenance, durability, and smoother performance. By replacing them when required you will benefit from smooth and noise-free rides.

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