FHP (fractional horsepower) V-belts are designed for light duty drives powered by motors under 1 to 2 HP. They use the same wedge-shaped cross section and friction-drive principle as industrial V-belts, but are built to lighter construction standards with thinner cord and lighter rubber compounds. FHP belts are designated by an "L" suffix: 2L, 3L, 4L, and 5L, where the number indicates the belt's top width in eighths of an inch.
Texas Belting stocks FHP V-belts in all four standard sections from Gates, Bando, and Diesel Belting. 4L is the most commonly requested section. Same-day shipping on stocked lengths from Houston.
Shop by Section
FHP V-Belt Cross Section Dimensions
| Section | Top Width | Depth | HP Range | Min. Sheave OD | Typical Applications |
|---|---|---|---|---|---|
| 2L | 1/4" (6.4 mm) | 3/16" (4.8 mm) | Under 1/4 HP | 0.75" | Very small motors, instruments, office equipment, small fans |
| 3L | 3/8" (9.5 mm) | 7/32" (5.6 mm) | Under 1/2 HP | 1.0" | Small appliances, bathroom exhaust fans, sewing machines, small shop tools |
| 4L | 1/2" (12.7 mm) | 5/16" (8 mm) | Under 1 HP | 1.5" | Furnace blowers, washing machines, dryers, lawn mowers, small compressors, bench tools |
| 5L | 21/32" (16.7 mm) | 3/8" (9.5 mm) | Under 2 HP | 2.5" | Residential HVAC blowers, light commercial fans, riding mowers, large appliances |
FHP Part Number Guide
FHP V-belt part numbers use the section designation followed by the outside circumference multiplied by 10. This is the same system used by narrow wedge (3V, 5V, 8V) belts, not the inside-length system used by classical (A, B, C) belts.
| Part Number | Section | Outside Circumference |
|---|---|---|
| 3L250 | 3L | 25.0" |
| 3L350 | 3L | 35.0" |
| 4L350 | 4L | 35.0" |
| 4L460 | 4L | 46.0" |
| 4L590 | 4L | 59.0" |
| 4L780 | 4L | 78.0" |
| 5L590 | 5L | 59.0" |
| 5L700 | 5L | 70.0" |
How to calculate: Measure the outside circumference (OC) by wrapping a tape around the top surface of the belt. Multiply by 10 to get the part number suffix. OC 59.0" becomes 4L590.
FHP vs. Industrial V-Belts: Know the Difference
The most common confusion involves 4L and A section belts, which share the same 1/2" x 5/16" cross-section dimensions. They physically fit in the same sheave groove. However, they are built differently:
| Feature | 4L (FHP) | A (Industrial) |
|---|---|---|
| Cross section | 1/2" x 5/16" | 1/2" x 5/16" (same) |
| Construction | Lighter cord, lighter rubber compound | Heavier cord, industrial-grade rubber |
| Load rating | Under 1 HP | Up to 10 HP |
| Part number system | OC x 10 (e.g., 4L590 = 59.0" OC) | Inside length (e.g., A57 = 57" inside) |
| Sheave compatibility | Fits A groove sheaves | Fits A groove sheaves (same) |
| Cost | Lower | Higher |
| Best for | Appliances, small motors, light commercial HVAC | Industrial pumps, fans, compressors, machinery |
The same relationship applies at 3/8" width: 3L (FHP) overlaps with 3V (narrow wedge industrial). 3L is for very light duty only. For industrial applications at 3/8" width, use 3V or 3VX.
Common Applications for FHP V-Belts
| Application | Typical Section | Notes |
|---|---|---|
| Residential furnace blowers | 4L, 5L | The single most common FHP belt application. 4L for standard furnaces, 5L for larger units. |
| Washing machines | 4L | Top-load washers with belt-driven agitators. Specific lengths per machine model. |
| Clothes dryers | 4L | Drum drive belt. Long, thin belt wrapping around the drum. |
| Walk-behind lawn mowers | 4L | Blade drive or self-propel drive. Outdoor/dusty environment. |
| Riding mowers / garden tractors | 4L, 5L | Deck drive and transmission drive. Multiple belts on some models. |
| Small air compressors (under 1 HP) | 3L, 4L | Pancake and hot dog compressors for home and shop use. |
| Bench grinders and small shop tools | 3L, 4L | 1/4 to 3/4 HP shop motors. |
| Bathroom and kitchen exhaust fans | 2L, 3L | Very small motors. Short belts. |
| Sewing machines (industrial pedal-drive) | 2L, 3L | Treadle-drive and clutch-motor sewing machines. |
| Light commercial HVAC | 4L, 5L | Small rooftop units and split systems under 2 HP. |
Finding the Right FHP Belt for Your Equipment
FHP belts are often specified by the equipment manufacturer using an OEM part number that does not match the standard belt designation. A furnace manufacturer might list the belt as "Part #12345" in the owner's manual, which is actually a standard 4L590 belt.
To find the correct standard FHP belt:
- Check the existing belt. The standard part number (e.g., 4L590) is usually printed on the belt even if the equipment manual uses an OEM number.
- Check the equipment manual. Some manuals list the standard belt size alongside the OEM number.
- Measure the belt. Width, depth, and outside circumference give you the section and part number.
- Search the OEM number. Texas Belting cross-references OEM equipment part numbers to standard belt sizes. Call 888-203-2358 with your equipment make, model, and OEM part number.
Frequently Asked Questions
FHP stands for Fractional Horsepower. FHP V-belts are designed for drives powered by motors under 1 to 2 HP, as opposed to industrial V-belts (A, B, C, D, E) which handle motors from 1 HP to 500+ HP. The four FHP sections are 2L, 3L, 4L, and 5L.
4L is the most common FHP section by far. It covers furnace blowers, washers, dryers, lawn mowers, and small compressors. The most frequently ordered 4L lengths include 4L350, 4L460, 4L590, 4L620, and 4L780, though the actual most common length depends on the equipment.
FHP belt part numbers use outside circumference times 10. Measure the OC by wrapping a tape around the top of the belt. Multiply by 10. A 4L belt measuring 59.0" OC is a 4L590.
4L is 1/2" wide x 5/16" deep, rated under 1 HP. 5L is 21/32" wide x 3/8" deep, rated under 2 HP. 5L handles slightly higher loads and is used on larger residential HVAC units, riding mowers, and light commercial equipment. They use different sheave grooves and are not interchangeable.
Yes. Texas Belting stocks the most popular 4L and 5L lengths at our Houston warehouse for same-day shipping. 2L and 3L sections are available in common lengths with short lead times on less common sizes. Call 888-203-2358 to check availability.
V-Belt Drive Components
FHP belts use light duty sheaves sized for their section. 4L fits A-groove sheaves, but 2L, 3L, and 5L each require their own groove profile. Browse our V-belt drive components, or see our Sheave Selection Guide for help choosing the right one.
Related Pages
Need an FHP V-Belt?
Texas Belting stocks FHP V-belts in 2L through 5L sections. Send us the part number, equipment make/model, or belt measurements and we will match it.
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