Bottom bracket: Difference between revisions

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== Types ==
== Types ==


[[Cartridge or Sealed]]
== Cartridge or Sealed ==
 
All the moving parts are housed within the tubing of a sealed bottom bracket, making them relatively easy to install, but basically impossible to repair. If the axle does not move freely or experiences up and down play, the whole bottom bracket needs replacing.
 
On a sealed bottom bracket, there is one free cup (which can be removed from the rest of the bracket) and one fixed cup, which is truly fixed in this case. The fixed cup is reverse threaded.
 
'''Installations:'''
 
# Install the fixed cup first, into the chain ring side of the bike. Remember is reverse threaded. It should go in as tightly as possible.
# Install the free cup second on the opposite side of the bike. In the case of the sealed bottom bracket, the free cup should also be on as tightly as possible. The threading on the free cup should be [[Righty Tighty, Lefty Loosey]].


Identified off the bike by the roughly 1" tubing around the axle.
Identified off the bike by the roughly 1" tubing around the axle.

Revision as of 02:52, 2 December 2007

Bottom Brackets are what your crank arms attach to spin.

Types

Cartridge or Sealed

All the moving parts are housed within the tubing of a sealed bottom bracket, making them relatively easy to install, but basically impossible to repair. If the axle does not move freely or experiences up and down play, the whole bottom bracket needs replacing.

On a sealed bottom bracket, there is one free cup (which can be removed from the rest of the bracket) and one fixed cup, which is truly fixed in this case. The fixed cup is reverse threaded.

Installations:

  1. Install the fixed cup first, into the chain ring side of the bike. Remember is reverse threaded. It should go in as tightly as possible.
  2. Install the free cup second on the opposite side of the bike. In the case of the sealed bottom bracket, the free cup should also be on as tightly as possible. The threading on the free cup should be Righty Tighty, Lefty Loosey.

Identified off the bike by the roughly 1" tubing around the axle.

Cup & Cone/ Unsealed

These have a lock ring and have either a threaded or cotter pin axle.

One Piece

Commonly found on inexpensive BMX bikes.

References