Introduction

In Part 1, we covered the types of pulleys grips actually use on set. Now let’s talk about what they do for us.

Mechanical advantage (or MA) is what makes a pulley system more than just a shiny wheel on a bracket. It's how you turn 100 pounds of effort into 200 pounds of lift—or vice versa. If you’ve ever pulled a line and thought, “Huh, that felt lighter than it should’ve,” you were likely working with mechanical advantage.

It’s not magic. It’s leverage. And knowing how much advantage to build into your system is just as important as knowing how to rig it in the first place.

Grip Math: The Sand Bag Analogy

Let’s put this in terms every grip can relate to.

You show up to set. Trucks unloaded. Carts staged. It’s time to move some stands through a narrow house and out back to set up. The problem? You’re short on crew, and the key calls for ten 20-pound sandbags. You’ve got to get all ten to the backyard.

You’ve got three ways to tackle this:

Option 1 (1:1):

You beast mode it—stack all ten bags (200 lbs) and make one trip. Dangerous, inefficient, but technically fast.

→ You’re applying full effort for full load: 1:1.

Option 2 (10:1):

You take one bag at a time. Easy on your body, but ten slow trips.

→ Minimal effort, high time cost: 10:1.

Option 3 (5:1):

You grab two at a time. Five trips. Manageable and reasonable.

→ Balanced effort and time: 5:1.

In all three cases, the total work done is the same: 200 lbs moved from A to B. But the perceived effort and efficiency changes depending on how you break it up. The same total effort gets spread out differently across time, trips, and muscle. That’s the essence of mechanical advantage. It’s not about doing less work—it’s about distributing it in a way that works for you, your gear, and the time you’ve got.

This same logic applies directly to the pulley systems we rig on set. Whether you’re lifting a flyswatter rig or tensioning a cable cam, your choice of MA can mean the difference between a clean pull and a bad time.

Mechanical Advantage = Load / Effort

Diving Deeper: How MA Actually Works

What Is Mechanical Advantage?

We’ve discussed mechanical advantage in grip terms so now let’s start to dig into semantics. A system’s mechanical advantage is expressed as a ratio with a colon.

For example:

A 2:1 system means for every 2 lbs of load, you only need to apply 1 lb of force to lift. If you're lifting a 200 lb load with a 2:1 system, you'll only have to pull with 100 lbs of effort.

But how do you figure out what the mechanical advantage is?

It comes down to one simple question:

How many lines are supporting the load?

That’s your MA—as long as those lines are actually bearing weight, not just redirecting.

Important: A single pulley does not automatically mean you have mechanical advantage. If it’s just changing the direction of your pull and mounted to a fixed anchor, it’s a redirect—not an advantage.

What Makes A Pulley Provide Mechanical Advantage?

Let’s look at 2 setups:

2:1 vs 1:1 mechanical advantage (MA)

Notice the positioning of the singular pulley in each. The pulley on the right is used for redirection. A pulley on the anchor like this shows doesn’t add any mechanical advantage. It only changes the direction of the pull.

The pulley on the left is attached to the load. A pulley on the load creates mechanical advantage.

When calculating your MA ratio, do not count ropes that are only used for redirection. This means we can count two ropes side by side on the left since the pulley is attached to the load and only 1 rope on the right since the pulley is attached to the anchor and serves as a redirect only.

Making 2:1 Practical for Grips

If two rope strands are holding up the load, and you’re pulling on a third, that’s a 2:1.

Pulling upward on a 2:1 isn’t always ideal—especially if the load starts below you. In this instance, you can add a pulley on the anchor of a 2:1 for a redirection which makes a 2:1 more practical for grip work.

2:1 system with a redirect (change in direction)

The Role of Friction & Efficiency

In theory, these systems work with ideal (100%) efficiency. In reality? Friction eats away at that.

Most pulley efficiencies range from 50–98%. Let’s hope your gear leans closer to that 98%—and that you’re not using carabiners as pulleys.

Tip: Pulleys with large sheave diameters and ball bearings are the most efficient.

Another Way to Calculate MA

If you’ve already built the system, you can also measure how much rope you have to pull to lift the load a certain distance. If you pull 4 feet of rope and the load rises 1 foot, you’ve got a 4:1 system.

This method works, but it’s reactive—after setup. So don’t rely on it for pre-rig planning.

Work = force x distance. All a mechanical advantage system allows you to do is apply less force to move the load over a greater distance. Total work stays the same.

Understanding Pulley System Types

Simple Systems

• One rope is used between one or more pulleys on the anchor and the load

• All of the pulleys that move do so at the same speed and in the same direction as the load

Compound Systems

• One simple system pulls on another simple pulley system

• Traveling pulleys move at different speeds than the load

• Mechanical advantage of each separate pulling system is multiplied

Complex Systems

• Pulleys move in opposite directions to the load

• Requires system resets as opposing pulleys will ultimately meet each other and run out of space

• Doesn’t cleanly fit “simple” or “compound” categories

Building Common Pulley Systems

Here’s how to think about the systems we actually build on set:

1:1 System

• Can be set up as just a straight object pull, but we most often use 1 change of direction pulley

• Pulley attached to an anchor serves as the redirect

• End of the rope is attached to your load

• Makes it easier to lift up your load by changing the pulling direction down instead of up but does not provide any mechanical advantage because the change of direction is on the fixed anchor

• Important to note that when you pull, the force on the anchor is approximately twice the force you’re applying to the rope

• Every foot of rope pulled through the system will also raise the load by 1 foot

General rule: A redirect on the anchor increases the load on the anchor

Practical Use Cases:

• Very lightweight softboxes

• Counterweight on a moving camera rig

• Hanging lightweight set dressing where speed matters more than assistance

2:1 System

• If we take a 1:1 system and turn it upside down it then turns into a 2:1 mechanical advantage

• A 2:1 system pulls with about half as much force as the weight of the load

• The pulley is not attached to an anchor, it is attached to the load

• End of the rope is tied up high

• A redirect pulley sends the rope back down to the ground where the grip applies effort to lift the load but does not provide a MA

• You pull 2’ of rope and the load moves 1’

Practical Use Cases:

• Speedrail tri truss / ladder truss hanging positions on stage

• Medium sized softboxes (8x8 or 12x12)

• Tensioning flyswatter belly lines (A trucker’s hitch gives a theoretical 2:1, but with way less efficiency)

3:1 System

• Can use a double block up high or two separate pulleys if you want progress capture. The second pulley up high is just a redirect

• Pull effort is one-third of load (theoretically)

• Pulleys are attached up high and also to the load

• End of the rope is tied to the load

• Watch your rope length - especially on long pulls

Practical Use Cases:

• Heavy set pieces

• Softboxes with lights integrated

A few key takeaways:

• A pulley on the anchor just changes direction. No MA.

• A pulley on the load provides mechanical advantage.

• Redirects create friction = less real-world MA.

• MA increases force on the anchor—plan accordingly.

• Theoretical MA isn’t what you’ll actually feel—friction, line stretch, and pulley quality all play a role.

• Don’t use carabiners as pulleys unless you’re really in a pinch.

• Don’t overbuild MA. Use what you need—and no more.