Start with the profile
In an SPA pulley code, the SPA portion identifies the narrow V-belt profile family. Keep that profile separate from neighboring SPZ, SPB and SPC sections. A replacement process should not begin by assuming that any V-groove wheel with a similar diameter is interchangeable.
Record the diameter exactly as labelled
Supplier catalogues may identify pitch, datum or outside diameter. Preserve the label that belongs to the value you measured or copied. Do not move a number between columns simply because it looks close to another catalogue row.
Count the grooves
Groove count changes the face width and belt quantity. A one-groove pulley is not the same catalogue object as a three-groove version at the same nominal diameter.
Separate the bushing code
On a taper-bush pulley, the bushing designation and its shaft bore are separate from the pulley profile and diameter. Photograph both markings when available.
Measure the shaft interface
Confirm shaft diameter, keyway and available axial length. If the existing bushing is damaged or unmarked, those measurements become even more important.
Use the machine data as context
For a new drive or a suspected mismatch, add driver and driven speeds, power or torque, center distance and duty cycle. Those inputs help determine whether the pulley family and diameter belong in the drive at all.
RFQ summary
Send the visible code, belt marking, groove count, diameter, shaft/bushing information, quantity and photos. That package is normally more useful than a single photo of the wheel.
