What is the difference between 1/8 and 3/32?

Chain

Modern bicycles use roller chain to connect the cranks to the rear wheel. Chain drives are among the most efficient means of power transmission known. Chain size is specified by pitch and width. The pitch is the distance between rollers (1/2" on all modern bicycle chain). The width is the internal width where the sprocket teeth fit in. Bicycle chain comes in two basic widths:

• 1/8" chain is used on most single-speed bicycles, and bicycles with internal gearing.
  
• 3/32" chain is used on derailer equipped bicycles that have more than 3 speeds.
  
  

Chains for derailer applications also come in various external widths. Newer clusters which have more sprockets use chain with thinner side plates and flush rivets.

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