Selection starts with the drive, not the catalogue card. Gather power, driver speed, required driven speed, shaft diameters and the operating environment before choosing a diameter or groove count.
1. Identify the existing or required belt section
If this is a replacement, read the belt and old pulley markings first. SPA is a defined narrow V-belt profile; do not substitute SPZ or SPB because the overall diameter looks similar.
2. Calculate the candidate datum diameters
Use the speed ratio with pitch/datum diameter. Then select the nearest catalogue P values that fit the required ratio and available guard space.
3. Size the groove count with the belt rating
The number of grooves is a power-capacity decision that depends on speed, diameter and service factor. Use the belt manufacturer’s rating method rather than a fixed kW-per-groove rule.
4. Match the shaft with the taper bush
The pulley model table gives the bush and maximum bore. The RFQ still needs the actual shaft diameter and keyway.
5. Check installation and service constraints
Confirm axial space, alignment access, belt tensioning range, contamination and whether balancing or a special material/finish is required.
For model matching or a quotation, email [email protected] with the pulley marking, shaft diameter and application.