Engineering & mechanics
Open belt pitch length
Find the geometric belt length and wrap angles between two pulleys.
A clear answer. Here’s how.
Uses the exact external-tangent geometry of an open belt around two circular pitch diameters. Centre distance must exceed the sum of the pulley radii. Returns both pulley wrap angles and the total pitch-line length. Does not include belt stretch, pretension, standard stock-size rounding or crossed-belt geometry.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- First pulley pitch diameter (mm)
- 100
- Second pulley pitch diameter (mm)
- 250
- Shaft centre distance (mm)
- 600
Example result
- Open belt pitch length (mm)
- 1,759.16597903
- Small pulley wrap (degrees)
- 165.638488437
- Large pulley wrap (degrees)
- 194.361511563