Complete Guide To Bottom Brackets

July 16, 2018
Complete Guide To Bottom Brackets
Complete Guide To Bottom Brackets

Not long ago, there weren’t so many options for bottom brackets. You basically had a few standards and only had to contemplate spindle length, shell width and Italian threading or English in just a few instances. While the limited designs made for somewhat easy decision making by default, they really didn’t leave the rider with complete solutions.

Today, bike assembly is more complex. This means that choosing a bike with the right bottom brackets for the way you ride can be a bit more challenging. In the end, however, you’re left with more opportunities to customize your cycle to your biking lifestyle.

We almost see as many “standards” for bottom brackets now as there are brands of bikes. Each of them is touted as being the best option, of course, but the real best brackets are identified only by research and thought as to what type of options best suit the rider.

Read our complete guide to bottom brackets to help you decide which style is best for you.

Major Types of Bottom Bracket Systems

There are several of what riders refer to as “major” types of bottom brackets. These commonly used brackets have their advantages and disadvantages, much having to do with compatibility.

The main types of bottom brackets you’ll see on the market today include:

  • Conventional threading
  • BB90/BB95
  • PF86/82
  • BB30
  • BB30A
  • PF30

Other bottom bracket systems like BBright, BB386 EVO, and T47 are also popular.

Conventional Threading

While widely used today, conventional threading brackets aren’t a new invention. They’ve actually been brackets of choice for a couple of decades. The idea behind these kinds of brackets is pretty simple. When bearings are moved outboard from the shell, you can use a larger spindle.

In the current market, 24mm is considered the norm in comparison to the relatively small 17mm diameter of the square taper. You’ll sometimes find bottom brackets for 30mm spindles, but not often.

Threaded bottom brackets are superbly compatible with the large range of cranks that are available today. They’re perfect for many bikes because they separate the bearing and the frameset.

BB90/BB95 Bottom Brackets

Some bikes have BB90/BB95 bottom brackets which work by having bearings pressed directly into the bike frame. This can save weight and make for a stiffer frame.

BB90/BB95 bottom brackets are meant to function in an identical manner as conventional threading brackets and they do offer great compatibility, but the shell is wider, and it requires a separate press and bearing puller.


PF86/92 bottom brackets are similar to BB90/BB95 brackets and they are located on a bike in the place you’d typically find conventional threading brackets. They differ from BB90/BB95 brackets, however, in that they’re mounted in small cups before being pressed into the bike’s frame.

Along with these brackets, you’ll find at least a handful of other popular brackets that have their pros and cons, depending on the rider’s needs and preferences.

If you have questions about the best bike brackets for the way you ride, feel free to shoot us a message. We’re always happy to help you with issues relating to riding like one of the top concerns we hear about, how to properly lock your bike so it doesn’t get stolen.

Contact us to inquire about custom bike chains, bike accessories or even sixthreezero bike assembly.

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Complete Guide To Bottom Brackets