Belt Tension Calculator

We recommend stretching most unreinforced belts at least 5%. The calculated tensions are less accurate below 5% stretch because the tension curve becomes nonlinear and less consistent. Usually 83A/85A durometer belts are stretched 10%, and 92A/95A durometer belts are stretched 7.5%. Do not use this calculator to estimate tension for reinforced belts.

Bearing Load:  Standard 1.9" (50mm) diameter conveyor rollers are normally rated at 250 lbs (110 kg) maximum load. The plastic fixture that holds the bearing is the limiting factor. For idler pulleys the maximum load is determined by the bearing itself. Our idler pulleys use the 6203 bearing, rated at 600 lbs (270 kg) at typical conveyor speeds. Make sure that your belt tension does not exceed the rating of your application.