Sheave vs Pulley: What is the Difference?

Do you consistently struggle to differentiate between pulleys and sheaves? You are not alone! Which do you need for your damaged lawnmower? Which piece is right for the critical assembly line component that just broke? Confusion can be heightened when both terms are applied to seemingly similar products.

While it may seem as if the success of your business rests upon choosing the right one, the truth is much less dramatic. Most experts agree there is no significant difference between the two! However, because the question is so common, we dive into the precise definitions of each piece of equipment, hoping to get to the bottom of the confusion.

What is the Difference Between a Pulley and a Sheave?

Dictionary Definitions

When trying to decipher between a pulley and sheave, beginning with dictionary definitions can be helpful.

Merriam Webster defines a pulley as…

A sheave or small wheel with a grooved rim […] used to change the direction and point of application of a pulling force.

This seems to support our conclusion of little to no difference between a pulley and a sheave, as even the dictionary uses the two terms interchangeably. The definition of sheave confirms our understanding even further, defining a sheave as…

A grooved wheel or pulley for hoisting or hauling, or for transmitting force to a cable or belt.

Again, we see that the terms pulley and sheave are used interchangeably. Both are grooved and used to apply force in a more efficient way. Based on definitions alone, differences between the two appear nominal.

Most Common Misconceptions

While we have already concluded there really is no significant difference between a pulley and a sheave, it may be helpful to consider why people seem to confuse the two. The phrasing is largely preferential, coming down to factors such as geographic location and industry standards.

• When business owners or homeowners talk about a sheave, most are referring to a smooth pulley for use with a cable, rope, or v-belt. On the other hand, when they discuss their need for a pulley, a timing pulley is often referenced!
• Phrasing also often differs by industry. For example, marine engineers typically distinguish between pulleys and sheave, while outdoor power equipment manufacturers often consider the two as equals. For some engineers, the difference can come down to what sort of system the pulley or sheave is used in.
• Phrasing often differs by geographical location too, just as some parts of the country refer to their favorite bubbly drink as “soda,” while other locations use either the word “pop” or “coke.” In the Midwest, sheave is often the preferred terminology, while pulley is more popular along the coasts.

Therefore, it seems that not even the experts can agree on the exact reasoning that differentiates a pulley and a sheave. So, how can you be sure you are getting the exact part you need?

What is a Timing Pulley, and How Do I Know if I Need One?

Timing belt pulleys work with timing belts to create a synchronous, non-slip transmission of movement. The timing belt pulley supports changes in belt direction and movement in a smooth and even way. Timing belt pulleys are often manufactured for industrial applications, such as metal conveyor belts.

Illinois Pulley & Gear: Giving You Confidence to Choose the Right Part

At Illinois Pulley & Gear, we engineer a wide range of timing belt pulleys, timing pulley stock, and replacement parts.  If you are unsure of the exact part you need, the best way to find out is to talk with our expert team. Regardless of your precise needs, our team will work closely with you to ensure that you are receiving exactly the right product you need for the job.

Our manufacturing process always begins with a conversation. As our team learns about your needs, we can address your concerns and design the high-quality part you need. Our Schaumburg facility is designed to make products on demand at a virtually unlimited variety. If you would like to talk more about the pulley (or sheave) you need, give us a call at 847.407.9595 or fill out our contact form.