How To Measure a Pulley Belt Size

V-belts are rubber belts wrapped around pulleys that transmit force as an engine rotates the pulleys.In order to choose the right belt for your pulleys, you need to have an accurate measurement of the length.It is easy to measure a pulley belt size.If you already have a belt that you need to measure, you can use a flexible measuring tape or read the belt codes.You can use the pulleys to find the right size if you don’t have an existing belt to measure.

Step 1: A white marker is used to mark a line across the belt.

Take a piece of chalk or a white marker and write a line on the outside of the belt.The line should be all the way across the belt.Make sure the line is thick enough to be visible while you measure.

Step 2: Attach the line on the belt to the measuring tape.

Wrap the tape measure around the belt.Measure from the end of the tape to the line you marked on the belt.If there is a metal clasp or plastic on the end of the measuring tape, make sure the marking is lined up exactly where the measurements begin.

Step 3: Wrap the measuring tape around the belt.

Wrap the tape measure around the belt with 1 hand.Make sure there aren’t any folds that affect your measurement by keeping it flush with the belt.Wrap the tape measure around the other end.The measuring tape needs to be tensioned so that it is accurate.

Step 4: You can note the distance by holding your finger where the tape meets the mark.

Once you have wrapped the measuring tape around the belt, use your index finger to mark where they meet and then remove it.The size of the pulley belt is where they meet.You can make a mark on the measuring tape or write down the measurement on a piece of paper for future reference.

Step 5: If there is no belt, use string.

If you want to find the size of a belt that is connected to pulleys without removing it, you should use a long piece of string.If there is no belt, you can use the pulleys to find the belt size.

Step 6: The string should be held on top of the belt or pulleys.

Pick a pulley to place the end of the string on top of.To hold the string in place, use one hand.It doesn’t matter if you have a belt attached to the pulley or not.

Step 7: Wrap the string around the pulleys.

Bring the string around the other pulley until it meets it, keeping the end against the pulley.Keeping the tension on the string is important.To connect the string to the end, hold it with your hand.

Step 8: Remove the string where it meets the other end.

You can use a marker to make a line on the string.Remove the string from the pulleys.The marking should be visible on the string.

Step 9: Measure the distance between the end of the string and the mark.

If you want the string to be straight and taut, place it on a flat surface.Measure the distance from the end of the string to the mark you made on the pulley belt using a ruler or tape measure.

Step 10: Look for a code on the belt’s surface.

Check the outer surface for a code printed in white letters if you need to measure the belt.The letters and numbers are repeated in multiple locations along the belt.You need to use the pulleys to determine the belt size if you don’t have a belt to measure.You may not be able to see the code printed on the surface if the belt is really worn.Measure the belt itself if that is the case.

Step 11: To identify a classical belt, look for an A, B, C, D, and E in front of the code.

A classical belt uses the letters A-E in the prefix to identify a specific top width and depth.The belt codes are determined by the inside diameter.To find the pulley belt length, you need to add the width of the belt to the measurement.Pick a replacement that has the same prefix so you know it fits the pulleys.

Step 12: The FHP belt can be identified by a 3L, 4L or 5L prefix.

FHP belts are often found in small machines.The belt code has a prefix that identifies an FHP belt.The outside measurement of the belt is designated by the FHP belt codes.The number following the FHP belt prefix is used to find the length of the belt.The belt is 36 inches long if the code reads 4L360.If you choose a replacement FHP with the same prefix, it will fit the pulleys.

Step 13: A Deep V-belt can be identified with a 3V, 5V or 8V prefix.

Deep V, also known as narrow belts, are often used in compact drives.To find the length of the belt, look for the number that follows the prefix and not the code.The length of the belt is 28 inches, if the code looks like 5V280.If you want to replace your Deep V-belt, choose a belt with the same prefix.