Full definition
The distance between the rotational axes of the driver and driven pulleys (or sprockets), a critical parameter in belt drive design. It directly determines belt length, wrap angle on the small pulley, and belt vibration characteristics. Minimum recommended: at least equal to the larger pulley diameter. Maximum: 3-5x the sum of both diameters (longer causes excessive belt sag and flutter). For V-belts, center distance adjustability of +3% (new belt installation) and -1.5% (take-up for stretch) is required per ISO 1081. Calculated iteratively: C ≈ (2L - π(D+d)) / 4, where L = belt pitch length, D and d are pulley diameters. Adjustable base or slot mounting is standard for tension adjustment.