How to Choose the Right V-Belt: Understanding Types A, B, C, D, and More
If you’ve ever looked at a belt catalog, you’ve probably seen codes like A, B, C, D, SPZ, and XPA. But what do they actually mean? Here’s a quick breakdown of the most common V-belt types — and how to pick the right one.
Why V-Belts?
V-belts are the most common flexible transmission elements in industrial drive systems. Their wedge-shaped cross-section increases friction and load capacity. The heavier the load, the tighter they grip. V-belts handle short-center drives and ratios up to 1:15, and run quietly. Since they’re endless-loop designs, there’s no joint failure risk.
Three Main V-Belt Families
V-belts are generally grouped into three families: Classical, Narrow, and Cogged.
1. Classical Series: Types A, B, C, D
These are the most widely used belts. The letter indicates cross-section dimensions and drive capacity.
| Type | Top Width (mm) | Height (mm) | Suitable For |
|---|---|---|---|
| A | 13 | 8 | Medium-duty drives, single or multiple belts |
| B | 17 | 11 | Medium-heavy industrial/agricultural drives |
| C | 22 | 14 | Heavy-duty, crushers, large machinery |
| D | 32 | 19 | High-horsepower heavy loads |
2. Narrow Series: XPZ, XPA, XPB, XPC
Narrower but stronger than classical types. Designed for compact, high-load, high-speed drives.
| Type | Top Width (mm) | Height (mm) | Suitable For |
|---|---|---|---|
| XPZ | 9.7 | 8 | Light loads, small pulleys, fans |
| XPA | 13 | 10 | General industrial, compressors, pumps |
| XPB | 17 | 14 | Medium-heavy, compact high-power drives |
| XPC | 22 | 18 | Heavy loads, crushers, large drives |
3. Cogged Belts
Cogged belts have teeth on the underside, making them more flexible and cooler-running. They’re great for small pulleys and high-speed continuous operation.
How to Read Belt Codes
Classical examples: B69 means type B, with a length of approx. 69 inches (about 1750mm).
Narrow examples: XPZ 1180 means type XPZ with a pitch length of 1180mm.
Selection Checklist
- Check old belt markings: Best starting point — match the printed code.
- Measure dimensions: If markings are gone, measure top width, height, and length.
- Consider your drive: Small pulleys? High speed? Narrow or cogged types are better. Heavy load? Look at C/D or SPB/SPC.
Quick Reference Table
| Series | Cross-Section | Best Use |
|---|---|---|
| A/B/C/D | Classical, widely available | Standard industrial, general replacement |
| XPZ/XPA/XPB/XPC | Narrow, stronger | Compact drives, high load, high speed |
| Cogged XPZ/XPA/XPB/XPC | Narrow + flexible | Small pulleys, high speed, continuous duty |
Compatibility Note: Brand equivalents vary. Always double-check with your existing belt dimensions.
If you’re not sure which type fits your equipment, feel free to send a photo of your old belt or its measurements — we’ll help you match the right replacement.