SHOP BY BRAND
or View All Brands
SHOP BY CATEGORY
Biking.com > Bikes & Frames > Bike Frame Parts > Bottom Bracket Shells and Parts
Bottom Bracket Shells and Parts

Bottom Bracket Shells and Parts

Narrow Your Search:   or:  




Get Exclusives & Discounts (Your Email Never Shared or Spammed):  

About Bottom Bracket Shells and Parts

 
Bike bottom brackets are bicycle parts that connect the crankset to the bicycle frame and provide a surface on which the cranks can rotate freely. They are part of the bike drivetrain components, which also include the cranksets and the freehubs/freewheel system at the rear wheel.
 
A bottom bracket contains a spindle onto which the crank attaches to (via bolts). It also contains bearings, usually ball bearings made of either metal or ceramic. These bearings lessen the surface friction, thus allowing the spindle and cranks to rotate smoothly. The cranks and spindle also attach to the chainring via spider, and this chainring in turn engages the chain which turns the rear gears.
 
The bottom bracket is fitted inside a bottom bracket shell, which is usually the main joint where the seat tube, down tube, and chain stays meet in most bike frames  designs today. Bottom bracket shells are technically bike frame parts, which also include the bike brake bosses (those little protrusions for holding cantilever brakes), and bike cable stops (another brazed-on bike frame part for engaging the bike cables).
 
The bottom bracket shell is a short and wide tube relative to the other tube parts of the bicycle frame. It runs from side to side and contains the bottom bracket. It is usually threaded (often left-hand thread) on the right side or the drive side of the bike. This is so in order to prevent accidental loosening by what is called “fretting induced precession”. Some versions of BB shell are unthreaded, such as the “eccentric” bottom bracket, which is usually larger and sometimes split.
 
 
LEARNING CENTER
TOP 50 BIKE CLUBS
FOR PHONE ORDERS 24 HOURS A DAY:
(800) 608-0254
$4.99 Shipping on Orders Over $50
Most orders ship same day
 Popular Brands
Gear Manufacturers
Shop Location
 Parts and Gear
Resources

 About Us
Privacy Policy
All Items
CLICK HERE TO CHAT LIVE
WITH A SALES REPRESENTATIVE