V-Belt RECOMMENDED PULLEY ALIGNMENT TOLERANCE VALUES

The standard tolerance limit for V-belt drive alignment is 0.5 degrees, and 0.25 degrees for synchronous drives.

Most major belt and pulley manufacturers specify these tolerance values. Pulley alignment can be set closer than this if the alignment procedure is carefully followed.

The following table converts degrees of misalignment to mils/inch and mm/100 (of pulley diameter) of misalignment between the projected planes of the pulley faces.

Angle Of Misalignment (degrees)  mm / 100mm  mils / inch
 0.1 0.18  1.75
 0.2  0.35  3.49
 0.3  0.52  5.24
 0.4  0.70  6.98
 0.5  0.87  8.73
 0.6  1.05  10.47
 0.7  1.22  12.22
 0.8  1.40  13.96
 0.9  1.57  15.71
 1.0  1.74  17.45

Bold = within recommended limits for V-belt drives

Note that the tolerance values between 0.1 and 0.5 fall within recommended misalignment limits for V-belt drives.