Bottom brackets rarely get the love or respect they deserve; until they go wrong. When they do fail or wear out, often riders know little about what bottom bracket their bike uses and consequently what replacement to buy or ask for. A quick word on threaded bottom bracket shell widths.
Nowadays, bottom brackets have disposable sealed cartridge bearings and, as frames have got beefier, bearings have increased in diameter to allow for lighter, stiffer chainsets using larger axles. And so goes the irresistible march of technological progress. However, while a traditional bottom bracket sits inside the frame and includes the axle in a single unit, Hollowtech bearings sit outside the frame and the axle is integrated into the crank.
The evolution of road bikes may have provided cyclists with frames that are lighter, stiffer and more aerodynamic, but there has also been a substantial increase in the number of bottom bracket and crank axle designs. The once ubiquitous threaded bottom bracket shell has given way to larger threadless designs while the diameter of crank axles has also grown. Both may have helped elevate the performance of contemporary road bikes but consumers have been left to contend with myriad options and some frustrating incompatibilities.
This article will discuss the removal and installation of the common cartridge bottom brackets of the three-piece cranksets. Most cartridge bottom brackets are held by retaining rings or cups on either side. See Adjustable-Type Bottom Brackets. One type has a fixed flange on the right side drive side.
By justin loretz. The humble bottom bracket BB gets subjected to some of the most intense and punishing conditions of any system on the bike. High loads are continuously channelled through rotational motion onto the bearings, which take the full brunt of both bodyweight and muscle power.
Bottom bracket service falls into one of two categories: you either change them with a new one or exchange bearings. Other brands do sell replacement bearings or seals to get the job done. Bikes with threadless bottom brackets PF30 or similar require you to punch out your old bearings using a BBT
By BikeRadar. This comprehensive guide tells you everything you need to know about bottom brackets — from a breakdown of all the bottom bracket systems available and their compatibility with one another to how a bottom bracket works and how to stop a bottom bracket creaking, this guide has it all. Below we rundown each of the major bottom bracket systems currently available, along with advantages, disadvantages, notes on compatibility, and some input from their proponents on why they exist:. Modern, external cup threaded bottom brackets are among the most common of standards.
A Shimano Hollowtech bottom bracket may have a shell made of metal or tough plastic. Shinamo Hollowtech bottom bracket s need a special ring spanner that fits into splines and allows each side to be screwed in and out. Push the ring spanner onto the external splines on the left side of the Shimano Hollowtech bottom bracket.
One is the press bit the other one is the threaded which is exactly what we've got on this bike. Here in this video we can show you how to remove and then replace a threaded bottom bracket. The only thing that you need for this job: A tool correctly fit onto the bottom bracket cups and probably a torque wrench if you want to do things correctly.