V-Belts

How to Calculate the Length (or Development) of a Trapezoidal Belt?

The length of the trapezoidal belt can usually be read directly from the stamping on it.

If the code on the belt cannot be read, for instance, due to wear, you can proceed to manual measurement and calculate the development according to the tables provided later.

It should be noted that for classic trapezoidal belts, the internal development is indicated as the standard reference, whereas for narrow trapezoidal belts, prefixed SP or XP, the primitive development is usually indicated.

To know the length of a belt, simply measure the EXTERNAL LENGTH manually, recording the measurement in millimeters, and then calculate the internal or primitive length based on the indications from the tables below.

After measuring the external length, which is usually easier and quicker to measure, simply subtract or add the values indicated in the table to the measured value in millimeters to obtain the actual development.

To practically measure the length of your belt, you can use a specific measuring tool, a tape measure, or more easily you can use a common piece of twine.

Remember that it is normal to have a margin of error of about 5 mm during manual measurement.