Difference Between Flat belt and V Belt

Published: 5 Jul 2025

Machines need power to move, and belts help deliver it from the motor to other parts. Among the many types of belts, flat belts and V belts are the most common. They both transfer power but in different ways. In this article, we’ll look at the difference between flat belt and V belt, helping you understand how each works and where it fits best.

Flat Belt

Flat in shape with a wide, thin, rectangular body. The belt is much wider than it is thick.
Only the bottom surface of the belt makes contact with the pulley. It has less grip.
It has low grip and can slip when the load increases or the belt becomes loose.
It works with simple, smooth pulleys that are cheap and quick to build.
Works well at high speeds but can only carry light to medium loads.
Very efficient at high speeds. It runs quietly and creates less friction.
Can work over long distances, sometimes more than 10 to 15 meters.
It can be used in both straight (open) and crossed setups to change direction.
It may produce some noise, especially if it has joints or is loose on the pulley.
Needs exact alignment. A small error can cause belt slip or wear.
Slips easily under overload, which helps protect the motor.
Needs more care, like cleaning and tension checking. Wears out faster over time.
Mostly used horizontally, especially on machines with wide spacing.
Found in conveyors, mills, and light-duty machines. Used in clean, dry areas.
Performs efficiently with speed ratios up to 4:1. Ideal for simple speed control.
Very low cost. It’s easy to buy and replace when it’s worn out.
The flat belt moves the power by pressing flat against the pulley’s surface.

V Belt

It has a V shape with slanted sides. It fits tightly into the matching pulley grooves.
The slanted sides fit into the pulley groove, helping the belt hold tightly and not slip.
It grips better due to its shape and wedge action, which stops slipping in most cases.
V-belt needs special V-grooved pulleys. These are stronger but more costly than flat pulleys.
It can carry heavy loads easily and works well at medium speeds with a strong grip.
Slightly less efficient due to more contact, but stronger when more power is needed.
This Belt is best for short distances, usually between 0.5 and 1 meter.
It is only used in straight (open) setups. A crossed setup is not possible with V belts.
It runs more quietly because it is endless and fits tightly into the groove.
It can still work if the alignment is slightly off. It stays in place better.
Grips tightly and rarely slips, but may still do so if the load is too heavy.
It lasts longer with less care. It needs fewer checks and is more durable.
Can work in any direction horizontally, vertically, or in angled positions.
Found in cars, compressors, pumps, and industrial machines with heavy loads.
It can go up to a 7:1 speed ratio. Good for high-power and torque applications.
It is Costly because it gives better service and longer life on heavy-use machines.
A wedge action between the belt and groove enables power transmission.

Conclusion

Understanding the difference between a flat belt and a V-belt helps you pick the right one.

To decide between a flat belt vs V belt, ask yourself the following:

How far are the pulleys?
How much load does the machine need?
What speed and power are required?

This will help you pick the best belt for your machine. And that means better work and a longer life for your machine!