How to Choose Between a Single or Dual Weight Stack for Your Home Gym

You're building out your home gym and cable machines are on the list. Smart move. Cables open up a world of exercises that free weights alone can't touch, from smooth lat pulldowns to chest-scorching crossovers. But before you click "add to cart," there's a decision to make: do you need one weight stack or two?

The answer depends on the exercises you plan to do and how much versatility you want from your setup. We talked to Thomas Rush, a member of REP's customer support team who holds a Master's in Coaching and Exercise Science along with certifications including CSCS and USA Weightlifting Level 1, to break down what actually matters when choosing between single and dual stack systems.

Understanding Pulley Ratios

Before diving into stack counts, it helps to understand what's happening behind the scenes. According to Rush, the key difference between cable systems comes down to their pulley ratio.

"A 1:1 pulley ratio means the feel of the weight for an exercise is exactly the same as the weight selected on the stack," Rush explains. "The cable moves the exact same distance as the weight stack. This is primarily used on single stack machines for heavier exercises, like a lat pulldown and low row."

A 2:1 pulley ratio works differently. Rush notes that with this setup, "the feel of the weight for an exercise is half of the actual weight of the stack selected." Pin 100 pounds and you're pulling against 50 pounds of resistance. The tradeoff is you get twice the cable travel, which makes these systems ideal for functional trainer movements that need a wider range of motion.

Some companies offer 4:1 ratios for even more cable travel, but Rush points out this isn't the most practical setup. "You would need quite a lot of weight plates and a large weight stack to provide enough versatility across a range of movements," he says.

Single Stack Systems

Single stack cable machines typically use a 1:1 pulley ratio and are built for one thing —  pulling heavy. You'll get this with dedicated lat pulldown and low row stations like the REP® Adonis™. These machines come equipped with leg rollers to anchor you during pulldowns and a foot plate to brace against during rows, so you can actually use the heavier loads they're designed to handle.

Best for:

• Lat pulldowns and seated rows as primary movements.
• Lifters who want to load up and chase progressive overload on back exercises.
• Home gyms where space or budget limits equipment to a dedicated pull station.

The downside of a single stack machines with 1:1 ratios is they aren't great for traditional functional trainer work. Limited cable travel means you can't get the full range needed for exercises like chest flyes or rotational movements. The weight jumps also feel bigger, which can be awkward for lighter accessory work.

Dual Stack Functional Trainers

Dual stack functional trainers — like the Arcadia™ — are the Swiss Army knife of cable machines. With two independent weight stacks and a 2:1 pulley ratio, you get massive exercise variety. Each arm can work alone for unilateral training or together for bilateral movements like cable crossovers.

"A dual stack gives the most versatility for functional trainer exercises, as you can use it for both exercises that use a single cable like bicep curls, tricep pushdowns, etc., and also exercises that use two cables like cable crossovers," says Rush.

Best for:

• Versatile training with single-arm curls, tricep pushdowns, cable flyes, and crossovers.
• Lifters who want one machine to cover a wide range of exercises.
• Athletes who need to train rotational and functional movements.

The caveat is that dual stack functional trainers aren't best designed for things like lat pulldowns or low rows, according to Rush. "This is mainly due to the weight restrictions from the 2:1 pulley ratio, but also, standalone functional trainers don't come with a low row foot plate or leg rollers to hold your legs down."

The Best of Both Worlds

If you want the flexibility of a functional trainer without giving up heavy pull capability, there are hybrid options worth considering. The REP® ATHENA™ rack attachment lets you configure a single or dual stack setup depending on your needs, so you can customize based on the exercises you prioritize.

For lifters who truly want it all, Rush recommends the REP ARES™ 2.0. "The REP ARES™ 2.0 uses a 2:1 pulley system throughout, and you will see two weight stacks and a cable exit point on each side to be used as a functional trainer," he explains. "However, the REP ARES™ 2.0 also has two endpoints at the top of the rack on the center for a lat pulldown, and two at the bottom in the center for a low row."

You can use these center attachment points separately for unilateral work or combine them for heavy bilateral pulling. "They can be combined together with our included 2-to-1 connector bar to create a 1:1 ratio," Rush adds. This means you get functional trainer versatility plus legit heavy pulling capability without adding extra stacks.

Making the Call

Here's how to narrow down your choice.

Choose single stack if: You're primarily training back with lat pulldowns and rows, want maximum loading potential, and don't need functional trainer versatility.

Choose dual stack if: You want one machine that handles everything from isolation exercises to crossovers and you're okay with lighter effective resistance on heavy pulls.

Consider a hybrid like the ATHENA® or REP ARES™ 2.0 if: You want full functional trainer capability AND heavy pull options without compromising on either.

Takeaway

Single and dual stack cable systems each have their strengths. Single stacks with 1:1 ratios let you load up for serious back work, while dual stack functional trainers open up a world of exercise variety with their 2:1 ratio and independent arms. If you can't decide, hybrid options like the ATHENA® and REP ARES™ 2.0 let you have your cake and eat it too. Think about the exercises you'll do most, the space you have, and whether you'd rather specialize or keep your options wide open.

FAQs

What's the difference between a 1:1 and 2:1 pulley ratio?

A 1:1 ratio means the weight you select is the resistance you feel, and the cable moves the same distance as the stack. A 2:1 ratio gives you half the resistance but twice the cable travel, making it better for functional trainer exercises that need range of motion.

Can I do lat pulldowns on a dual stack functional trainer?

You can, but it's not usually ideal. Dual stack functional trainers usually lack the leg rollers that keep you anchored during heavy pulldowns. However, the ARES™ 2.0 cable system allows you to connect both stacks with the 2-to-1 Bar Connector so you can target lat pulldowns and low rows.

Is one weight stack enough for a home gym?

It depends on your goals. If you're focused on back training with pulldowns and rows, a single stack machine built for those movements is plenty. If you want to do a wide variety of cable exercises, a dual stack functional trainer gives you more flexibility.

What makes the REP ARES™ 2.0 different from other functional trainers?

The REP ARES™ 2.0 includes dedicated lat pulldown and low row attachment points in addition to the standard functional trainer cables. A 2-to-1 connector bar combines the cables for a 1:1 ratio on heavy pulls, so you get both functional trainer versatility and proper pulling station performance.