How to Size Your Industrial V-Belts

Selecting Industrial Belts

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Sizing Your V-Belts

You need to determine the width and length of your industrial v-belts to select the correct replacement.  You can use the numbers on your old belt to determine the correct size or measure it yourself.

V-Belt Width Measurements

Single Belts

Type of V-BeltWidth of Belt (Inches)

Banded Belts

All banded K, L, M v-belts will have the outside circumference in front of the letter. The rib count will be the number after the letter.

K Section= 0.140″ multiplied by the number of ribs

L Section= 0.185″ multiplied by the number of ribs

M Section= 0.370″ multiplied by the number of ribs

Examples of how banded v-belts are named:

K Section= (Example 845K8 = 84.5″ Outside Circumference and 8 Ribs)

L Section= (Example 540L10 = 54″ Outside Circumference and 10 Ribs)

M Section= (Example 940M6 = 94″ Outside Circumference and 6 Ribs)

V-Belt Lengths

A, B, C, D, E, AX, BX – Use Inside circumference length

All A, B, C, D, E, AX, and BX belts use the inner circumference measurement after the letter of the part number. If you measured the outer circumference, then you would subtract the number of inches based on the type of belt to obtain the belt number. This is also the same for the banded belts.

Examples of how belt numbers are coded per type of belt:

A Section= Add 2″ to belt number (Example A88 = 90″ Outside Circumference)

B Section= Add 3″ to belt number (Example B88 = 91″ Outside Circumference)

C Section= Add 4″ to belt number (Example C88 = 92″ Outside Circumference)

D Section= Add 5″ to belt number (Example D105 = 110″ Outside Circumference)

E Section= Add 6″ to belt number (Example E144 = 150″ Outside Circumference)

AX Section= Add 2″ to belt number (Example AX60 = 62″ Outside Circumference)

BX Section= Add 3″ to belt number (Example BX50 = 53″ Outside Circumference)

3L, 3V, 5V, 8V, 3VX, 5VX – Use Outside circumference length

All 3L, 3V, 5V, 8V, 3VX, and 5VX v-belts use the outside circumference after the far-left number and letter(s) to show belt length. The Inside circumference is not measured for these types of belts. It is the same for banded belts. Measure each individual band for banded belts to obtain the correct width.

Examples of how belt numbers are coded per section:

3L Section= (Example 3L450 = 45″ Outside Circumference)

3V Section= (Example 3V800 = 80″ Outside Circumference)

5V Section= (Example 5V1180 = 118″ Outside Circumference)

8V Section= (Example 8V2120 = 212″ Outside Circumference)

3VX Section= (Example 3VX520 = 52″ Outside Circumference)

5VX Section= (Example 5VX810 = 81″ Outside Circumference)


How to Measure the Circumference of a V-Belt

The most accurate way to measure a belt is to measure the circumference with a cloth tape measure, not by folding the belt in half. Another way is to use a string to determine length, then measure the length of the string. Please keep in mind that belts stretch and there is no proven way to determine the amount a belt will stretch before it needs replacement.