Chain and Sprocket Chain Length

Methodology of how to identify “Roller Chain Length” for a chain and sprocket drive.

Author - Tony Voiklis Power Transmission Technical Specialist.

How many pitches/links do I need for this chain drive? The following describes a basic methodology.

It’s important to cut and install the correct roller chain length between the two sprockets. Roller chain tension being either too tight or too loose will affect both longevity and drive efficiency. You will find more information on how to adjust chain tension (SAG) in section 4.

Following is a formula to determine the Roller Chain Length:

Z = Sprocket DriveR No. of Teeth + Sprocket DriveN No. of Teeth x Chain Pitch (in inches)
Divide by 2
Y = 2 x Shafts Centre Distance (in inches)
Z + Y = Q (Chain length in INCHES)

To determine chain length in feet divide Q by 12.

To determine chain length in pitches divide Q by chain pitch (in inches).

Example for 19 tooth and 21 tooth sprockets with 0.75” pitch chain, as follows;

Z = Sprocket DriveR No. of Teeth 19T + Sprocket DriveN No. of Teeth 21T x Chain Pitch 0.75” (in inches)
Divide by 2
Z = 15”
Y = 2 x 22” Shafts Centre Distance (in inches)
Y = 44”
(15”) Z + (44”) Y = Q (Chain length in inches)
Q = 59” (Chain length in inches)

To determine chain length in feet divide (59”) Q by 12 = 4.92ft required.

To determine chain length in pitches divide (59”) Q by chain pitch 0.75” (in inches) = 79 pitches required, eg. 80 pitches of chain.

Contact CBC for further information on Power Transmission Drive applications.

Article - Methodology on how to identify “Roller Chain Length” for a chain and sprocket drive.