Center Distance and Belt Length

The relationship between center distance and belt pitch length is given by the following formula:

relationship between center distance and belt pitch length formula

where:

Lp = pitch length of belt, inches
C = center distance, inches
D = pitch diameter of large pulley, inches
d = pitch diameter of small pulley, inches
ø = sin–1 (D-d/2C), degrees

The approximate center distance can be found by this formula:

approximate center distance formula

where: K = 4L – 6.28 (D+d)

The exact center distance can then be determined by trial, using the belt pitch length formula, or use center distance tables available from belt manufacturers.

You can also use our online tool

Center Distance Calculator

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The is equal to some multiple of the pitch of the belt. For example, the belt length increment of XL section (0.200 pitch) must be 0.200, 0.400, 0.600, etc.