Bottom Bracket

The bottom bracket on a bicycle connects the crankset to the bicycle and allows the crankset to rotate freely. It is not a bracket as such. It contains a spindle that the crankset attaches to, and the bearings that allow the spindle and cranks to rotate. The chainrings and pedals attach to the cranks. The bottom bracket fits inside the bottom bracket shell, which connects the seat tube, down tube and chain stays as part of the bicycle frame.

There is some disagreement as to whether the word axle or spindle should be used in particular contexts. The distinction is based on whether the axle/spindle is stationary, as that in a hub, or rotates, as that in a bottom bracket. Sheldon Brown uses axle once and spindle four times in his bottom bracket glossary entry. This article uses spindle throughout for consistency.

An old American term for bottom bracket is hanger. This is usually used in connection with Ashtabula cranks, alternately termed one-piece cranks.

Read more about Bottom BracketInterface Types, Sizes, Bottom Bracket Height, Eccentric Bottom Brackets

Other articles related to "bottom bracket, bracket, bottom":

Kickstand - Types
... Side stands can be mounted to the chain stays right behind the bottom bracket or to a chain and seat stay near the rear hub ... Side stands mounted right behind the bottom bracket can be bolted on, either clamping the chain stays, or to the bracket between them, or welded into place as an integral part of the frame ... A center stand kickstand is a pair of legs or a bracket that flips straight down and lifts the rear wheel off the ground when in use ...
List Of Bicycle Parts
... Bottle cage - a holder for a water bottle Bottom bracket - The bearing system that the pedals (and cranks) rotate around ... The bottom bracket may be overhaulable (an adjustable bottom bracket) or not overhaulable (a cartridge bottom bracket) ... The bottom bracket fits inside the bottom bracket shell, which is part of the bicycle frame ...
Cable Guide - Above The Bottom Bracket
... Cable guides above the bottom bracket are usually made of metal, causing more friction and wear on the cable, and is a more complex cable guide as it does not follow the shape of the bottom ...
Eccentric Bottom Brackets
... is a cylindrical plug or bearing cup that fits into an enlarged bottom bracket shell ... The plug is machined to accept a typical bottom bracket, but offset from the center of the plug, so that by rotating the plug, the location of the bottom bracket (and ... the plug is then fixed in place by a pair of set screws, a clamping bottom bracket shell, an expanding wedge in the plug, or the plug may be manufactured in left and right halves that clamp ...
Bicycle Suspension - Rear Suspension - Unified Rear Triangle
... pivot is placed between the rear triangle and the front triangle so that the rear axle and bottom bracket move as one piece, and the saddle and handlebars move ... of the swing-arm and distance between the bottom bracket and the pivot, and as a result the suspensions effectiveness is reduced to some extent ...

Famous quotes containing the word bottom:

    Women are supposed to be deep—why? Because one can never get to the bottom with them. Women are not even shallow.
    Friedrich Nietzsche (1844–1900)