Even the most experienced bike mechanics can get a bit nervous when it comes to bottom brackets. There are so many different standards out there and so many different tools you need to use to take them off. So whether you’re just starting out or you’re an experienced rider, here’s what you should know about the bottom bracket on your bike.
What is a bottom bracket?
The bike bottom bracket connects your crank and connects the cranks to the bike frame. It’s basically a jacket to store the bearings that enable you to ride your bike with ease.
How often should it be repaired?
In the past, bike bottom brackets were typically designed to undergo multiple regreseal or lubrication cycles as part of regular bicycle maintenance. However, the majority of bottom brackets are now designed to be replaced as soon as they become worn out. Generally, bottom brackets are expected to last for a period of 1-2 years, which is typical for most riders. However, it is possible that a bottom bracket may need to be replaced more frequently if:
It’s exposed to water, or if you’re riding in mud or dirt a lot, or if you hear a creaking sound, or if it was installed improperly.
What kind of bottom brackets are available?
The most common types of bottom brackets are Threaded, PressFit, and Thread-together.
If you have a bike that’s less than a decade old, you probably have one of the three below-mentioned bottom bracket standards. But that’s just the beginning. Bottom brackets vary in width depending on the type of bike you’re riding, and different bike parts manufacturers use different tools to remove cranks (or pull them out). The best way to figure out which one you have is to check out your bike manufacturer’s website. But if that doesn’t work, we’ve got a few other ways to tell you apart.
Press fit bottom brackets
PressFit bottom brackets are sometimes referred to as “unthreaded”. The bottom bracket shell slides into the frame and a “cup” is pressed into it. In almost all cases, tool fittings do not protrude from the shell or from the frame.
PressFit is more common on carbon frames.
Threaded bottom brackets
It looks like they are making a big comeback! A lot of bike techs break it down into a cup and cone adjustment, cartridge style, and outer bearing systems. Basically, all of these systems uses threads for tightening the bottom bracket. Most bikes from the last 10 years use bearing system that is external, which means both the frame shell and the cup of the bottom bracket are threaded together.
Thread thru bottom bracket
Thread-Thru bottom brackets are very much akin to the Press Fit bottom bracket in that they have a smooth, unthreaded shell as well as threaded cups. The difference is that instead of threading through the frame of the bottom bracket, they thread into each other. The left and rightcups are then joined together within the smooth shell of the bottom bracket.
How to remove a bottom bracket?
- Figure out what type of crank you have. You probably only need upto 10 Allen Wrenches, but sometimes you need special tools.
- Once you’ve removed the crank, use tools of the correct size to remove the cup. Once you’re done, turn it around until it’s completely free. Then, squeeze out the cups.