How To Identify Your Belt
How to Identify Your Belt
The complete guide to identifying V-belts, timing belts, and conveyor belts. Learn how to read part numbers, measure belt dimensions, and find the correct replacement — or send us a photo and we'll identify it for you.
The Fastest Way to Identify Any Belt
Three steps. Works for V-belts, timing belts, and conveyor belts.
Read the Part Number
Check the belt's outer surface for a printed or embossed part number. V-belt formats: A68, B75, 5V1060, 3VX355, 4L590. Timing belt formats: 300L, 480H, 8M1200.
Measure If Number Is Gone
If the number is worn off, measure the belt's top width, depth (height), and outside circumference. For timing belts, also measure tooth pitch (center-to-center distance between teeth).
Call or Email Us
Send the part number, measurements, or even just a photo to sales@texasbelting.com. We'll confirm the correct replacement — usually within the hour.
How to Identify a V-Belt
V-belts are identified by a letter prefix (the cross-section type) followed by a number (the length). The letter tells you the belt's width and depth profile. The number tells you the inside or outside circumference depending on the section type.
How to Read a V-Belt Part Number
Classical V-Belts (A, B, C, D, E)
The letter is the cross-section. The number is the inside circumference in inches. To convert from an outside measurement, subtract the factor for that section.
Example: A belt marked B100 — "B" means B-section (5/8" top width), "100" means 100" inside circumference.
Cogged V-Belts (AX, BX, CX)
Same dimensions as their classical counterpart but with molded cogs on the underside. The "X" suffix indicates cogged construction. Cogged belts flex better around smaller pulleys, run cooler, and are more efficient.
Example: BX80 is a cogged B-section belt with an 80" inside circumference. Direct replacement for a B80.
Narrow Wedge V-Belts (3V, 5V, 8V)
Narrower and deeper than classical belts, delivering higher power capacity in a compact drive. The number prefix indicates nominal top width in 1/8" increments (3V = 3/8", 5V = 5/8", 8V = 1").
Example: 5V1060 is a 5V-section belt. "1060" is the outside circumference in tenths of inches (106.0").
Light Duty / FHP Belts (2L, 3L, 4L, 5L)
Fractional Horsepower belts for light-duty applications like HVAC fans, appliances, lawn equipment. The number prefix indicates top width in 1/8" increments (3L = 3/8", 4L = 1/2", 5L = 5/8").
Example: 4L590 — "590" is the outside circumference in tenths of inches (59.0"). A 4L belt is interchangeable with an A-section in many applications.
V-Belt Part Number Conversion Factors
If you can only measure the outside circumference, subtract the factor below to calculate the part number.
| Section | Top Width | Depth | Subtract from OC | Length = | Example |
|---|---|---|---|---|---|
A / AX |
1/2" | 5/16" | 2" | Inside circumference | OC 70" → 70 - 2 = A68
|
B / BX |
5/8" | 13/32" | 3" | Inside circumference | OC 103" → 103 - 3 = B100
|
C / CX |
7/8" | 17/32" | 4" | Inside circumference | OC 102" → 102 - 4 = C98
|
D |
1-1/4" | 3/4" | 5" | Inside circumference | OC 149" → 149 - 5 = D144
|
E |
1-1/2" | 29/32" | 6" | Inside circumference | OC 246" → 246 - 6 = E240
|
3L |
3/8" | 7/32" | — | OC in tenths of inches | OC 22" → 3L220
|
4L / A |
1/2" | 5/16" | — | OC in tenths of inches | OC 59" → 4L590
|
5L / B |
5/8" | 13/32" | — | OC in tenths of inches | OC 62" → 5L620
|
3V / 3VX |
3/8" | 5/16" | — | OC in tenths of inches | OC 35.5" → 3V355
|
5V / 5VX |
5/8" | 17/32" | — | OC in tenths of inches | OC 106" → 5V1060
|
8V / 8VX |
1" | 7/8" | — | OC in tenths of inches | OC 200" → 8V2000
|
How to Measure a V-Belt (When the Number Is Gone)
Measure the Top Width
Lay the belt flat and measure straight across the widest (top) surface. This determines the section: 1/2" = A, 5/8" = B, 7/8" = C, 1-1/4" = D, 1-1/2" = E.
Measure the Depth
Measure from the top surface to the bottom of the V. Don't measure along the angled side — measure straight through the middle. This confirms the section type and distinguishes classical from narrow wedge.
Measure the Outside Circumference
Wrap a flexible tape measure around the outside (top) of the belt. For classical belts (A, B, C, D, E), subtract the conversion factor to get the part number. For FHP and narrow wedge, multiply OC by 10 for the part number suffix.
Check for Cogging
Flip the belt over. If the inside surface has molded notches or "cogs," add an "X" suffix (AX, BX, CX, 3VX, 5VX). Cogged and non-cogged belts share the same dimensions and are interchangeable.
How to Identify a Timing Belt
Timing belts (synchronous belts) have teeth that mesh with grooved pulleys for positive, no-slip power transmission. They're identified by tooth pitch (profile type), pitch length, and belt width.
How to Read a Timing Belt Part Number
Imperial Timing Belts (XL, L, H, XH, XXH)
The number is the pitch circumference in tenths of inches. The letters indicate the tooth pitch.
Example: 480H = 48.0" pitch circumference, H-profile (1/2" pitch). 300L = 30.0" pitch circumference, L-profile (3/8" pitch).
Metric Timing Belts (HTD, GT, RPP)
The number before the letter is the pitch circumference in mm. The number after is tooth pitch (3M = 3mm, 5M = 5mm, 8M = 8mm, 14M = 14mm).
Example: 1200-8M = 1200mm pitch circumference, 8mm tooth pitch. Also written 8M1200.
Timing Belt Tooth Pitch Reference
| Profile | Tooth Pitch | System | Typical Applications | Example |
|---|---|---|---|---|
MXL |
0.080" (2.032mm) | Imperial | Miniature drives, instruments | 68MXL |
XL |
1/5" (5.08mm) | Imperial | Light-duty, business machines, printers | 190XL |
L |
3/8" (9.525mm) | Imperial | Medium-duty industrial, HVAC, conveyors | 300L |
H |
1/2" (12.7mm) | Imperial | Heavy-duty industrial, machine tools | 480H |
XH |
7/8" (22.225mm) | Imperial | Heavy industrial, large drives | 700XH |
XXH |
1-1/4" (31.75mm) | Imperial | Very large industrial drives | 1400XXH |
3M |
3mm | Metric HTD | Light-duty, precision positioning | 3M-420 |
5M |
5mm | Metric HTD | General industrial, packaging | 5M-600 |
8M |
8mm | Metric HTD/GT | Heavy-duty industrial, conveyors | 8M-1200 |
14M |
14mm | Metric HTD/GT | High-power, mining, large machinery | 14M-2100 |
How to Measure a Timing Belt
Measure the Tooth Pitch
Measure center of one tooth to center of the next. Common pitches: 3/8" (L), 1/2" (H), 5mm (5M), 8mm (8M). Use a caliper — this is the most important timing belt measurement.
Count the Teeth
Count total teeth on the belt. Multiply teeth x pitch = pitch circumference. Example: 96 teeth x 1/2" = 48.0" → 480H.
Measure the Width
Measure belt width straight across. Standard widths: 1/4", 1/2", 3/4", 1", 1-1/2", 2", 3". Width is specified separately when ordering.
How to Identify a Conveyor Belt
Conveyor belts are identified by construction type, material, width, number of plies, cover type, and total thickness. Unlike V-belts and timing belts, conveyor belts don't always follow a universal part numbering system — specifications vary by manufacturer.
Key Specifications to Identify
Construction Type
FBS (Friction Both Sides) — Fabric texture on both sides. Designed for slider bed conveyors. Lower friction on the slider bed.
COS (Cover One Side) — Smooth PVC or rubber cover on top, fabric bottom. Most common type. Good for slider beds and general conveying.
CBS (Cover Both Sides) — Smooth cover on both top and bottom. Required for live roller conveyors and elevator/bucket elevator applications.
Material and Properties
PVC — Most common. White (FDA food grade), black, green, blue. Oil resistant, anti-static, flame retardant options.
Rubber — Heavy-duty. SBR, nitrile, neoprene compounds. Heat, oil, and abrasion resistant.
Urethane — Chemical resistant, FDA compliant, oil resistant. Food processing and metalworking.
PTFE / Silicone — High-temperature applications (ovens, heat tunnels, shrink wrap).
How to Measure a Conveyor Belt for Replacement
Belt Width
Measure straight across edge to edge. Common widths: 6", 12", 18", 24", 30", 36", 42", 48", 54", 60", 72". Belt width is typically 1-2" narrower than the conveyor frame.
Belt Length
Endless belts: measure total circumference around the full loop. Open-end: measure flat end to end. On the conveyor: measure center-to-center distance x 2, plus pulley circumference.
Number of Plies and Thickness
Look at the belt edge to count fabric plies (layers). Common: 2-ply, 3-ply, 4-ply. Measure total thickness with a caliper. This determines tensile strength and minimum pulley diameter.
Cover Type and Surface
Note the top surface (smooth, rough top, textured, cleated) and bottom (fabric, smooth). Identify FBS, COS, or CBS. Note the color — white typically indicates FDA food grade.
Splice Type
How the belt is joined: finger splice (vulcanized), overlap splice, mechanical lacing (clipper, plate grip), or endless (no splice). This determines how we fabricate the replacement.
V-Belt Cross Section Size Chart
Measure your belt's top width to determine the section type.
| Top Width | Classical | Cogged | FHP Equiv. | Narrow Wedge | Narrow Cogged | Application |
|---|---|---|---|---|---|---|
| 3/8" | — | — | 3L |
3V |
3VX |
Light duty, HVAC, small equipment |
| 1/2" | A |
AX |
4L |
— | — | Light to medium industrial |
| 5/8" | B |
BX |
5L |
5V |
5VX |
Medium to heavy industrial |
| 7/8" | C |
CX |
— | — | — | Heavy industrial |
| 1" | — | — | — | 8V |
8VX |
Very heavy industrial, mining |
| 1-1/4" | D |
— | — | — | — | Heavy industrial, large drives |
| 1-1/2" | E |
— | — | — | — | Very large industrial drives |
Pro Tip: Label Your Drives
To avoid the identification headache next time, label each drive on your equipment with the correct belt part number using an adhesive sticker or permanent marker. Also record the installation date — this helps schedule preventive replacement before belts fail.
Can't Identify Your Belt? We'll Do It for You.
If the part number is worn off and you're not sure about the measurements, don't guess — send it to us. Our team identifies belts every day and can usually confirm the correct replacement within the hour during business hours.
What to send us: A photo of the belt (showing the cross-section and any remaining markings), the equipment make/model if known, and any measurements you can take. Even partial information helps.
What you'll get back: The exact part number, pricing, availability, and shipping options. If we stock it, it often ships the same day.
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